new version 0_2_2 from stuttgart

.gitignore

@@ -3,8 +3,6 @@
 .pio/build
 .vscode
 *.ino.cpp
-config.h
-config.hftstuttgart.h
 .project
 .cproject
 .settings

.gitlab-ci.yml

@@ -2,29 +2,11 @@ image: python:3.6
 
 stages:
  - build
- - release
 
 before_script:
   - "pip install -U platformio"
   - "cp ampel-firmware/config.public.h ampel-firmware/config.h"
 
-esp8266:
+job:
   stage: build
-  script: 
+  script: "platformio run"
-    - "platformio run --environment esp8266"
-    - cp .pio/build/esp8266/firmware.bin esp8266.bin
-  artifacts:
-    paths:
-      - esp8266.bin
-    expire_in: 1 week
-
-release:
-    image: inetprocess/gitlab-release
-    stage: release
-    only:
-        - tags
-    dependencies: 
-        - esp8266
-    script:
-        - gitlab-release --message '' ./*.bin
-

CHANGELOG.md

@@ -0,0 +1,25 @@
+# Change Log
+
+## [v0.2.2](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-firmware/-/releases/v0.2.2) 2021/10/01
+
+* MAC address is now shown at startup and via HTTP
+
+## [v0.2.1](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-firmware/-/releases/v0.2.1) 2021/06/06
+
+* BUGFIX: Sensor would keep on calibrating after successful calibration.
+
+## [v0.2.0](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-firmware/-/releases/v0.2.0) 2021/06/06
+
+* BUGFIX: Calibration was not applied correctly (Thanks Michael Käppler for bug finding & fixing!)
+* MQTT works again for ESP32 (board needs to be updated in Arduino IDE/PlaftormIO)
+
+## [v0.1.0](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-firmware/-/releases/v0.1.0) 2021/05/19
+
+* More stable calibration, with 10s timestep
+* Allow commands from Serial/MQTT/Webserver
+* Many bugfixes
+
+## [v0.0.9](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-firmware/-/releases/v0.0.9) 2020/12/15
+
+* First CO2 Ampel release.
+* Basic functionality

README.md

@@ -1,6 +1,6 @@
 # CO<sub>2</sub> Ampel
 
-*CO<sub>2</sub> Ampel* is an open-source project, written in C++ for ESP8266 or ESP32.
+*CO<sub>2</sub> Ampel* is an open-source project, written in C++ for [ESP8266](https://en.wikipedia.org/wiki/ESP8266) or [ESP32](https://en.wikipedia.org/wiki/ESP32).
 
 It measures the current CO<sub>2</sub> concentration (in ppm), and displays it on an LED ring.
 
@@ -12,20 +12,20 @@ The *CO<sub>2</sub> Ampel* can:
 
 * Display CO2 concentration on LED ring.
 * Allow calibration.
-* Get current time over NTP
+* Get current time over [NTP](https://en.wikipedia.org/wiki/Network_Time_Protocol)
-* Send data over MQTT.
+* Send data over [MQTT](https://en.wikipedia.org/wiki/MQTT).
-* Send data over LoRaWAN.
+* Send data over [LoRaWAN](https://en.wikipedia.org/wiki/LoRa#LoRaWAN).
 * Display measurements and configuration on a small website.
-* Log data to a CSV file, directly on the ESP flash memory.
+* Log data to a [CSV](https://en.wikipedia.org/wiki/Comma-separated_values) file, directly on the ESP flash memory.
+* Accept many interactive commands.
 
 ## Hardware Requirements
 
 * [ESP8266](https://en.wikipedia.org/wiki/ESP8266) or [ESP32](https://en.wikipedia.org/wiki/ESP32) microcontroller (this project has been tested with *ESP8266 ESP-12 WIFI* and *TTGO ESP32 SX1276 LoRa*)
 * [Sensirion SCD30](https://www.sensirion.com/en/environmental-sensors/carbon-dioxide-sensors/carbon-dioxide-sensors-co2/) "Sensor Module for HVAC and Indoor Air Quality Applications"
-* [NeoPixel Ring - 12](https://www.adafruit.com/product/1643)
+* [NeoPixel Ring - 12](https://www.adafruit.com/product/1643), or [NeoPixel Ring - 16](https://www.adafruit.com/product/1463) (experimental)
 
-See the [original documentation](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-documentation) for more info.
+See the [documentation](https://transfer.hft-stuttgart.de/gitlab/co2ampel/ampel-documentation) for more info.
-Or our Wiki [MakerLab Wiki CO2 Ampel](https://wiki.makerlab-murnau.de/books/co2-ampel).
 
 ## Software Requirements
 
@@ -68,27 +68,49 @@ make upload board=esp32 && make monitor # For ESP32
 * *Upload*
 * *Tools > Serial Monitor*
 
+## Available commands
+
+In Arduino IDE *Serial Monitor* or PlatformIO *Monitor*, type `help` + <kbd>Enter</kbd> in order to list the available commands:
+
+* `auto_calibrate 0/1` (Disables/enables autocalibration).
+* `calibrate` (Starts calibration process).
+* `calibrate 600` (Starts calibration process, to given ppm).
+* `calibrate! 600` (Calibrates right now, to given ppm).
+* `co2 1500` (Sets co2 level, for debugging purposes).
+* `color 0xFF0015` (Shows color, specified as RGB, for debugging).
+* `csv 60` (Sets CSV writing interval, in s).
+* `format_filesystem` (Deletes the whole filesystem).
+* `free` (Displays available heap space).
+* `local_ip` (Displays local IP and current SSID).
+* `lora 300` (Sets LoRaWAN sending interval, in s).
+* `mqtt 60` (Sets MQTT sending interval, in s).
+* `night_mode` (Toggles night mode on/off).
+* `reset` (Restarts the ESP).
+* `reset_scd` (Resets SCD30).
+* `send_local_ip` (Sends local IP and SSID via MQTT. Can be useful to find sensor).
+* `set_time 1618829570` (Sets time to the given UNIX time).
+* `show_csv` (Displays the complete CSV file on Serial).
+* `timer 30` (Sets measurement interval, in s).
+* `wifi_scan` (Scans available WiFi networks).
+
+The commands can be sent via the Serial interface, from the webpage or via MQTT.
+
 ## Authors
 
- * Eric Duminil
+ * Eric Duminil (HfT Stuttgart)
- * Robert Otto
+ * Robert Otto (HfT Stuttgart)
- * Myriam Guedey
+ * Myriam Guedey (HfT Stuttgart)
- * Tobias Gabriel Erhart
+ * Tobias Gabriel Erhart (HfT Stuttgart)
- * Jonas Stave
+ * Jonas Stave (HfT Stuttgart)
-
+ * Michael Käppler
-Hochschule für Technik Stuttgart
-
-## Modifications by
-
-* Jens Noack
-
-MakerLab Murnau e.V.
 
 ## Contributing
-Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
+
+* Merge requests are welcome, and should be based on the `develop` branch.
+* The `develop` branch gets merged into the `master` once it has been sufficiently tested.
+* For major changes, please open an issue first to discuss what you would like to change.
 
 ## License
 
-Copyright © 2020, [HfT Stuttgart](https://www.hft-stuttgart.de/)
+Copyright © 2021, [HfT Stuttgart](https://www.hft-stuttgart.de/)
-
 [GPLv3](https://choosealicense.com/licenses/gpl-3.0/)

ampel-firmware/ampel-firmware.h

@@ -20,6 +20,12 @@
 #  ifdef AMPEL_HTTP
 #    include "web_server.h"
 #  endif
+#  if defined(ESP8266)
+     //allows sensor to be seen as SENSOR_ID.local, from the local network. For example : espd03cc5.local
+#    include <ESP8266mDNS.h>
+#  elif defined(ESP32)
+#    include <ESPmDNS.h>
+#  endif
 #endif
 
 #ifdef AMPEL_LORAWAN
@@ -27,17 +33,8 @@
 #endif
 
 #include "util.h"
+#include "sensor_console.h"
 #include "co2_sensor.h"
 #include "led_effects.h"
 
-#if defined(ESP8266)
-//allows sensor to be seen as SENSOR_ID.local, from the local network. For example : espd03cc5.local
-#  include <ESP8266mDNS.h>
-#elif defined(ESP32)
-#  include <ESPmDNS.h>
-#endif
-
-void keepServicesAlive();
-void checkFlashButton();
-
 #endif

ampel-firmware/ampel-firmware.ino

@@ -43,6 +43,7 @@
  * Myriam Guedey
  * Tobias Gabriel Erhart
  * Jonas Stave
+ * Michael Käppler
  */
 
 /*****************************************************************
@@ -64,19 +65,28 @@ void setup() {
   
   Serial.begin(BAUDS);
 
-  pinMode(0, INPUT); // Flash button (used for forced calibration)
+  pinMode(buttonPin, INPUT); // Flash button (used for forced calibration)
+
+  Serial.println();
+  Serial.print(F("Sensor ID: "));
+  Serial.println(ampel.sensorId);
+  Serial.print(F("MAC      : "));
+  Serial.println(ampel.macAddress);
+  Serial.print(F("Board    : "));
+  Serial.println(ampel.board);
+  Serial.print(F("Firmware : "));
+  Serial.println(ampel.version);
 
   led_effects::setupRing();
-
+  led_effects::showRainbowWheel(5000);
   sensor::initialize();
 
-  Serial.print(F("Sensor ID: "));
+#ifdef AMPEL_CSV
-  Serial.println(SENSOR_ID);
+  csv_writer::initialize(ampel.sensorId);
-  Serial.print(F("Board    : "));
+#endif
-  Serial.println(BOARD);
 
 #ifdef AMPEL_WIFI
-  WiFiConnect(SENSOR_ID);
+  wifi::connect(ampel.sensorId);
 
   Serial.print(F("WiFi - Status: "));
   Serial.println(WiFi.status());
@@ -88,7 +98,7 @@ void setup() {
 
     ntp::initialize();
 
-    if (MDNS.begin(SENSOR_ID.c_str())) { // Start the mDNS responder for SENSOR_ID.local
+    if (MDNS.begin(ampel.sensorId)) { // Start the mDNS responder for SENSOR_ID.local
       MDNS.addService("http", "tcp", 80);
       Serial.println(F("mDNS responder started"));
     } else {
@@ -96,24 +106,26 @@ void setup() {
     }
 
 #  ifdef AMPEL_MQTT
-    mqtt::initialize("CO2sensors/" + SENSOR_ID);
+    mqtt::initialize(ampel.sensorId);
 #  endif
   }
 #endif
 
-#ifdef AMPEL_CSV
-  csv_writer::initialize();
-#endif
-
 #if defined(AMPEL_LORAWAN) && defined(ESP32)
   lorawan::initialize();
 #endif
 }
 
+/*****************************************************************
+ * Helper functions                                              *
+ *****************************************************************/
+void keepServicesAlive();
+void checkFlashButton();
+void checkSerialInput();
+
 /*****************************************************************
  * Main loop                                                     *
  *****************************************************************/
-
 void loop() {
 #if defined(AMPEL_LORAWAN) && defined(ESP32)
   //LMIC Library seems to be very sensitive to timing issues, so run it first.
@@ -133,6 +145,8 @@ void loop() {
   // Short press for night mode, Long press for calibration.
   checkFlashButton();
 
+  checkSerialInput();
+
   if (sensor::processData()) {
 #ifdef AMPEL_CSV
     csv_writer::logIfTimeHasCome(sensor::timestamp, sensor::co2, sensor::temperature, sensor::humidity);
@@ -148,11 +162,17 @@ void loop() {
   }
 
   uint32_t duration = millis() - t0;
-  if (duration > max_loop_duration) {
+  if (duration > ampel.max_loop_duration) {
-    max_loop_duration = duration;
+    ampel.max_loop_duration = duration;
     Serial.print(F("Debug - Max loop duration : "));
-    Serial.print(max_loop_duration);
+    Serial.print(ampel.max_loop_duration);
-    Serial.println(" ms.");
+    Serial.println(F(" ms."));
+  }
+}
+
+void checkSerialInput() {
+  while (Serial.available() > 0) {
+    sensor_console::processSerialInput(Serial.read());
   }
 }
 
@@ -163,16 +183,18 @@ void loop() {
  *   If long press, start calibration process.
  */
 void checkFlashButton() {
-  if (!digitalRead(buttonPin)) { // Button has been pressed
+  if (!digitalRead(0)) { // Button has been pressed
     led_effects::onBoardLEDOn();
     delay(300);
-    if (digitalRead(buttonPin)) {
+    if (digitalRead(0)) {
       Serial.println(F("Flash has been pressed for a short time. Should toggle night mode."));
       led_effects::toggleNightMode();
     } else {
       Serial.println(F("Flash has been pressed for a long time. Keep it pressed for calibration."));
-      if (led_effects::countdownToZero() < 0) {
+      if (led_effects::countdownToZero()) {
+        Serial.println(F("You can now release the button."));
         sensor::startCalibrationProcess();
+        led_effects::showKITTWheel(color::red, 2);
       }
     }
     led_effects::onBoardLEDOff();

ampel-firmware/co2_sensor.cpp

@@ -1,10 +1,17 @@
 #include "co2_sensor.h"
 
 namespace config {
-  // Values should be defined in config.h
+  // UPPERCASE values should be defined in config.h
-  uint16_t measurement_timestep = MEASUREMENT_TIMESTEP; // [s] Value between 2 and 1800 (range for SCD30 sensor)
+  uint16_t measurement_timestep = MEASUREMENT_TIMESTEP; // [s] Value between 2 and 1800 (range for SCD30 sensor).
   const uint16_t altitude_above_sea_level = ALTITUDE_ABOVE_SEA_LEVEL; // [m]
   uint16_t co2_calibration_level = ATMOSPHERIC_CO2_CONCENTRATION; // [ppm]
+  const uint16_t measurement_timestep_bootup = 5; // [s] Measurement timestep during acclimatization.
+  const uint8_t max_deviation_during_bootup = 20; // [%]
+  const int8_t max_deviation_during_calibration = 30; // [ppm]
+  const int16_t timestep_during_calibration = 10; // [s] WARNING: Measurements can be unreliable for timesteps shorter than 10s.
+  const int8_t stable_measurements_before_calibration = 120 / timestep_during_calibration; // [-] Stable measurements during at least 2 minutes.
+  const uint16_t co2_alert_threshold = 2000; // [ppm] Display a flashing led ring, if concentration exceeds this value
+
 #ifdef TEMPERATURE_OFFSET
   // Residual heat from CO2 sensor seems to be high enough to change the temperature reading. How much should it be offset?
   // NOTE: Sign isn't relevant. The returned temperature will always be shifted down.
@@ -12,23 +19,46 @@ namespace config {
 #else
   const float temperature_offset = -3.0;  // [K] Temperature measured by sensor is usually at least 3K too high.
 #endif
-  const bool auto_calibrate_sensor = AUTO_CALIBRATE_SENSOR; // [true / false]
+  bool auto_calibrate_sensor = AUTO_CALIBRATE_SENSOR; // [true / false]
+  const bool debug_sensor_states = false; // If true, log state transitions over serial console
 }
 
 namespace sensor {
   SCD30 scd30;
-  int16_t co2 = 0;
+  uint16_t co2 = 0;
   float temperature = 0;
   float humidity = 0;
-  String timestamp = "";
+  char timestamp[23];
   int16_t stable_measurements = 0;
-  uint32_t waiting_color = color::blue;
+
-  bool should_calibrate = false;
+  /**
-  unsigned long time_calaibration_started = millis();
+   * Define sensor states
+   * BOOTUP -> initial state, until first >0 ppm values are returned
+   * READY -> sensor does output valid information (> 0 ppm) and no other condition takes place
+   * NEEDS_CALIBRATION -> sensor measurements are too low (< 250 ppm)
+   * PREPARE_CALIBRATION_UNSTABLE -> forced calibration was initiated, last measurements were too far apart
+   * PREPARE_CALIBRATION_STABLE -> forced calibration was initiated, last measurements were close to each others
+   */
+  enum state {
+    BOOTUP,
+    READY,
+    NEEDS_CALIBRATION,
+    PREPARE_CALIBRATION_UNSTABLE,
+    PREPARE_CALIBRATION_STABLE
+  };
+  const char *state_names[] = {
+      "BOOTUP",
+      "READY",
+      "NEEDS_CALIBRATION",
+      "PREPARE_CALIBRATION_UNSTABLE",
+      "PREPARE_CALIBRATION_STABLE" };
+
+  state current_state = BOOTUP;
+  void switchState(state);
 
   void initialize() {
 #if defined(ESP8266)
-    Wire.begin(12, 14);  // ESP8266 - SDA: D6, SCL: D5;
+    Wire.begin(12, 14); // ESP8266 - D6, D5;
 #endif
 #if defined(ESP32)
     Wire.begin(21, 22); // ESP32
@@ -40,81 +70,103 @@ namespace sensor {
      *  SDA --- SDA (GPIO21) //NOTE: GPIO1 would be more convenient (right next to GPO3)
      */
 #endif
-
-    // CO2
-    if (scd30.begin(config::auto_calibrate_sensor) == false) {
-      Serial.println("Air sensor not detected. Please check wiring. Freezing...");
-      while (1) {
-        led_effects::showWaitingLED(color::red);
-      }
-    }
-
-    // SCD30 has its own timer.
-    //NOTE: The timer seems to be inaccurate, though, possibly depending on voltage. Should it be offset?
     Serial.println();
-    Serial.print(F("Setting SCD30 timestep to "));
+    scd30.enableDebugging(); // Prints firmware version in the console.
-    Serial.print(config::measurement_timestep);
+
-    Serial.println(" s.");
+    if (!scd30.begin(config::auto_calibrate_sensor)) {
-    scd30.setMeasurementInterval(config::measurement_timestep); // [s]
+      Serial.println(F("ERROR - CO2 sensor not detected. Please check wiring!"));
+      led_effects::showKITTWheel(color::red, 30);
+      ESP.restart();
+    }
+
+    // Changes of the SCD30's measurement timestep do not come into effect
+    // before the next measurement takes place. That means that after a hard reset
+    // of the ESP the SCD30 sometimes needs a long time until switching back to 2 s
+    // for acclimatization. Resetting it after startup seems to fix this behaviour.
+    scd30.reset();
 
     Serial.print(F("Setting temperature offset to -"));
     Serial.print(abs(config::temperature_offset));
-    Serial.println(" K.");
+    Serial.println(F(" K."));
     scd30.setTemperatureOffset(abs(config::temperature_offset)); // setTemperatureOffset only accepts positive numbers, but shifts the temperature down.
     delay(100);
 
     Serial.print(F("Temperature offset is : -"));
     Serial.print(scd30.getTemperatureOffset());
-    Serial.println(" K");
+    Serial.println(F(" K"));
 
     Serial.print(F("Auto-calibration is "));
     Serial.println(config::auto_calibrate_sensor ? "ON." : "OFF.");
+
+    // SCD30 has its own timer.
+    //NOTE: The timer seems to be inaccurate, though, possibly depending on voltage. Should it be offset?
+    Serial.println();
+    Serial.print(F("Setting SCD30 timestep to "));
+    Serial.print(config::measurement_timestep_bootup);
+    Serial.println(F(" s during acclimatization."));
+    scd30.setMeasurementInterval(config::measurement_timestep_bootup); // [s]
+
+    sensor_console::defineIntCommand("co2", setCO2forDebugging, F("1500 (Sets co2 level, for debugging purposes)"));
+    sensor_console::defineIntCommand("timer", setTimer, F("30 (Sets measurement interval, in s)"));
+    sensor_console::defineCommand("calibrate", startCalibrationProcess, F("(Starts calibration process)"));
+    sensor_console::defineIntCommand("calibrate", calibrateSensorToSpecificPPM,
+        F("600 (Starts calibration process, to given ppm)"));
+    sensor_console::defineIntCommand("calibrate!", calibrateSensorRightNow,
+        F("600 (Calibrates right now, to given ppm)"));
+    sensor_console::defineIntCommand("auto_calibrate", setAutoCalibration, F("0/1 (Disables/enables autocalibration)"));
+    sensor_console::defineCommand("reset_scd", resetSCD, F("(Resets SCD30)"));
   }
 
-  //NOTE: should timer deviation be used to adjust measurement_timestep?
+  bool hasSensorSettled() {
-  void checkTimerDeviation() {
+    static uint16_t last_co2 = 0;
-    static int32_t previous_measurement_at = 0;
+    uint16_t delta;
-    int32_t now = millis();
+    delta = abs(co2 - last_co2);
-    Serial.print("Measurement time offset : ");
+    last_co2 = co2;
-    Serial.print(now - previous_measurement_at - config::measurement_timestep * 1000);
+    // We assume the sensor has acclimated to the environment if measurements
-    Serial.println(" ms.");
+    // change less than a specified percentage of the current value.
-    previous_measurement_at = now;
+    return (co2 > 0 && delta < ((uint32_t) co2 * config::max_deviation_during_bootup / 100));
   }
 
-  void countStableMeasurements() {
+  bool enoughStableMeasurements() {
     static int16_t previous_co2 = 0;
-    if (co2 > (previous_co2 - 30) && co2 < (previous_co2 + 30)) {
+    if (co2 > (previous_co2 - config::max_deviation_during_calibration)
+        && co2 < (previous_co2 + config::max_deviation_during_calibration)) {
       stable_measurements++;
       Serial.print(F("Number of stable measurements : "));
-      Serial.println(stable_measurements);
+      Serial.print(stable_measurements);
-      waiting_color = color::green;
+      Serial.print(F(" / "));
+      Serial.println(config::stable_measurements_before_calibration);
+      switchState(PREPARE_CALIBRATION_STABLE);
     } else {
       stable_measurements = 0;
-      waiting_color = color::red;
+      switchState(PREPARE_CALIBRATION_UNSTABLE);
     }
     previous_co2 = co2;
+    return (stable_measurements == config::stable_measurements_before_calibration);
   }
 
   void startCalibrationProcess() {
     /** From the sensor documentation:
-     * For best results, the sensor has to be run in a stable environment in continuous mode at
+     * Before applying FRC, SCD30 needs to be operated for 2 minutes with the desired measurement period in continuous mode.
-     * a measurement rate of 2s for at least two minutes before applying the FRC command and sending the reference value.
      */
-    Serial.println(F("Setting SCD30 timestep to 2s, prior to calibration."));
+    Serial.print(F("Setting SCD30 timestep to "));
-    scd30.setMeasurementInterval(MEASUREMENT_TIMESTEP); // [s] The change will only take effect after next measurement.
+    Serial.print(config::timestep_during_calibration);
+    Serial.println(F("s, prior to calibration."));
+    scd30.setMeasurementInterval(config::timestep_during_calibration); // [s] The change will only take effect after next measurement.
     Serial.println(F("Waiting until the measurements are stable for at least 2 minutes."));
     Serial.println(F("It could take a very long time."));
-    should_calibrate = true;
+    switchState(PREPARE_CALIBRATION_UNSTABLE);
-    time_calaibration_started = millis();
   }
 
-  void calibrateAndRestart() {
+  void calibrate() {
     Serial.print(F("Calibrating SCD30 now..."));
     scd30.setAltitudeCompensation(config::altitude_above_sea_level);
     scd30.setForcedRecalibrationFactor(config::co2_calibration_level);
     Serial.println(F(" Done!"));
     Serial.println(F("Sensor calibrated."));
-    ESP.restart(); // softer than ESP.reset
+    switchState(BOOTUP); // In order to stop the calibration and select the desired timestep.
+    //WARNING: Do not reset the ampel or the SCD30!
+    //At least one measurement needs to happen in order for the calibration to be correctly applied.
   }
 
   void logToSerial() {
@@ -127,29 +179,86 @@ namespace sensor {
     Serial.println(humidity, 1);
   }
 
-  void displayCO2OnLedRing() {
+  void switchState(state new_state) {
-    int16_t co2_int = co2;
+    if (new_state == current_state) {
-    if (co2_int < CALIBRATE_LEVEL) {
-      // Sensor should be calibrated.
-      led_effects::showWaitingLED(color::magenta);
       return;
     }
-    if(co2_int < 400) {
+    if (config::debug_sensor_states) {
-      co2_int = 400;
+      Serial.print(F("Changing sensor state: "));
+      Serial.print(state_names[current_state]);
+      Serial.print(F(" -> "));
+      Serial.println(state_names[new_state]);
     }
+    current_state = new_state;
+  }
+
+  void switchStateForCurrentPPM() {
+    if (current_state == BOOTUP) {
+      if (!hasSensorSettled()) {
+        return;
+      }
+      switchState(READY);
+      Serial.println(F("Sensor acclimatization finished."));
+      Serial.print(F("Setting SCD30 timestep to "));
+      Serial.print(config::measurement_timestep);
+      Serial.println(F(" s."));
+      if (config::measurement_timestep < 10) {
+        Serial.println(F("WARNING: Timesteps shorter than 10s can lead to unreliable measurements!"));
+      }
+      scd30.setMeasurementInterval(config::measurement_timestep); // [s]
+    }
+
+    // Check for pre-calibration states first, because we do not want to
+    // leave them before calibration is done.
+    if ((current_state == PREPARE_CALIBRATION_UNSTABLE) || (current_state == PREPARE_CALIBRATION_STABLE)) {
+      if (enoughStableMeasurements()) {
+        calibrate();
+      }
+    } else if (co2 < 250) {
+      // Sensor should be calibrated.
+      switchState(NEEDS_CALIBRATION);
+    } else {
+      switchState(READY);
+    }
+  }
+
+  void displayCO2OnLedRing() {
     /**
      * Display data, even if it's "old" (with breathing).
-     * Those effects include a short delay.
+     * A short delay is required in order to let background tasks run on the ESP8266.
+     * see https://github.com/esp8266/Arduino/issues/3241#issuecomment-301290392
      */
-    if (co2_int < 2000) {
+    if (co2 < config::co2_alert_threshold) {
-      led_effects::displayCO2color(co2_int);
+      led_effects::displayCO2color(co2);
-      led_effects::breathe(co2_int);
+      delay(100);
     } else {
-      // >= 2000: entire ring blinks red
+      // Display a flashing led ring, if concentration exceeds a specific value
       led_effects::redAlert();
     }
   }
 
+  void showState() {
+    switch (current_state) {
+    case BOOTUP:
+      led_effects::showWaitingLED(color::blue);
+      break;
+    case READY:
+      displayCO2OnLedRing();
+      break;
+    case NEEDS_CALIBRATION:
+      led_effects::showWaitingLED(color::magenta);
+      break;
+    case PREPARE_CALIBRATION_UNSTABLE:
+      led_effects::showWaitingLED(color::red);
+      break;
+    case PREPARE_CALIBRATION_STABLE:
+      led_effects::showWaitingLED(color::green);
+      break;
+    default:
+      Serial.println(F("Encountered unknown sensor state")); // This should not happen.
+    }
+  }
+
   /** Gets fresh data if available, checks calibration status, displays CO2 levels.
    * Returns true if fresh data is available, for further processing (e.g. MQTT, CSV or LoRa)
    */
@@ -157,42 +266,75 @@ namespace sensor {
     bool freshData = scd30.dataAvailable();
 
     if (freshData) {
-      // checkTimerDeviation();
+      ntp::getLocalTime(timestamp);
-      timestamp = ntp::getLocalTime();
       co2 = scd30.getCO2();
       temperature = scd30.getTemperature();
       humidity = scd30.getHumidity();
-    }
 
-    //NOTE: Data is available, but it's sometimes erroneous: the sensor outputs zero ppm but non-zero temperature and non-zero humidity.
+      switchStateForCurrentPPM();
-    if (co2 <= 0) {
-      // No measurement yet. Waiting.
-      led_effects::showWaitingLED(color::blue);
-      return false;
-    }
 
-    /**
+      // Log every time fresh data is available.
-     * Fresh data. Log it and send it if needed.
-     */
-    if (freshData) {
-      if (should_calibrate) {
-        if(millis() - time_calaibration_started > 60000)
-        {
-          countStableMeasurements();
-        }
-      }
       logToSerial();
     }
 
-    if (should_calibrate) {
+    showState();
-      if (stable_measurements == 60) {
+
-        calibrateAndRestart();
+    // Report data for further processing only if the data is reliable
-      }
+    // (state 'READY') or manual calibration is necessary (state 'NEEDS_CALIBRATION').
-      led_effects::showWaitingLED(waiting_color);
+    return freshData && (current_state == READY || current_state == NEEDS_CALIBRATION);
-      return false;
   }
 
-    displayCO2OnLedRing();
+  /*****************************************************************
-    return freshData;
+   * Callbacks for sensor commands                                 *
+   *****************************************************************/
+  void setCO2forDebugging(int32_t fakeCo2) {
+    Serial.print(F("DEBUG. Setting CO2 to "));
+    co2 = fakeCo2;
+    Serial.println(co2);
+    switchStateForCurrentPPM();
+  }
+
+  void setAutoCalibration(int32_t autoCalibration) {
+    config::auto_calibrate_sensor = autoCalibration;
+    scd30.setAutoSelfCalibration(autoCalibration);
+    Serial.print(F("Setting auto-calibration to : "));
+    Serial.println(autoCalibration ? F("On.") : F("Off."));
+  }
+
+  void setTimer(int32_t timestep) {
+    if (timestep >= 2 && timestep <= 1800) {
+      Serial.print(F("Setting Measurement Interval to : "));
+      Serial.print(timestep);
+      Serial.println(F("s (change will only be applied after next measurement)."));
+      scd30.setMeasurementInterval(timestep);
+      config::measurement_timestep = timestep;
+      led_effects::showKITTWheel(color::green, 1);
+    }
+  }
+
+  void calibrateSensorToSpecificPPM(int32_t calibrationLevel) {
+    if (calibrationLevel >= 400 && calibrationLevel <= 2000) {
+      Serial.print(F("Force calibration, at "));
+      config::co2_calibration_level = calibrationLevel;
+      Serial.print(config::co2_calibration_level);
+      Serial.println(F(" ppm."));
+      startCalibrationProcess();
+    }
+  }
+
+  void calibrateSensorRightNow(int32_t calibrationLevel) {
+    if (calibrationLevel >= 400 && calibrationLevel <= 2000) {
+      Serial.print(F("Force calibration, right now, at "));
+      config::co2_calibration_level = calibrationLevel;
+      Serial.print(config::co2_calibration_level);
+      Serial.println(F(" ppm."));
+      calibrate();
+    }
+  }
+
+  void resetSCD() {
+    Serial.print(F("Resetting SCD30..."));
+    scd30.reset();
+    Serial.println(F("done."));
   }
 }

ampel-firmware/co2_sensor.h

@@ -7,24 +7,32 @@
 #include "config.h"
 #include "led_effects.h"
 #include "util.h"
+#include "sensor_console.h"
 #include <Wire.h>
 
 namespace config {
   extern uint16_t measurement_timestep; // [s] Value between 2 and 1800 (range for SCD30 sensor)
-  extern const bool auto_calibrate_sensor; // [true / false]
+  extern bool auto_calibrate_sensor; // [true / false]
   extern uint16_t co2_calibration_level; // [ppm]
   extern const float temperature_offset; // [K] Sign isn't relevant.
 }
 
 namespace sensor {
   extern SCD30 scd30;
-  extern int16_t co2;
+  extern uint16_t co2;
   extern float temperature;
   extern float humidity;
-  extern String timestamp;
+  extern char timestamp[];
 
   void initialize();
   bool processData();
   void startCalibrationProcess();
+
+  void setCO2forDebugging(int32_t fakeCo2);
+  void setTimer(int32_t timestep);
+  void calibrateSensorToSpecificPPM(int32_t calibrationLevel);
+  void calibrateSensorRightNow(int32_t calibrationLevel);
+  void setAutoCalibration(int32_t autoCalibration);
+  void resetSCD();
 }
 #endif

ampel-firmware/config.h

@@ -1,7 +1,6 @@
 #ifndef CONFIG_H_INCLUDED
 #define CONFIG_H_INCLUDED
 
-
 #define buttonPin 0
 // This file is a config template, and can be copied to config.h. Please don't save any important password in this template.
 
@@ -24,8 +23,8 @@
  * WIFI
  */
 
-#  define WIFI_SSID     ""
+#  define WIFI_SSID     "MY_SSID"
-#  define WIFI_PASSWORD ""
+#  define WIFI_PASSWORD "P4SSW0RD"
 #  define WIFI_TIMEOUT  30 // [s]
 
 /**
@@ -33,8 +32,10 @@
  */
 
 // How often should measurement be performed, and displayed?
-//NOTE: SCD30 timer does not seem to be very precise. Variations may occur.
+//WARNING: On some sensors, measurements become very unreliable when timestep is set to 2s.
-#  define MEASUREMENT_TIMESTEP 2 // [s] Value between 2 and 1800 (range for SCD30 sensor)
+//NOTE: 10s or longer should be fine in order to get reliable results.
+//NOTE: SCD30 timer does not seem to be very precise. Time variations may occur.
+#  define MEASUREMENT_TIMESTEP 5 // [s] Value between 2 and 1800 (range for SCD30 sensor)
 
 // How often should measurements be appended to CSV ?
 // Probably a good idea to use a multiple of MEASUREMENT_TIMESTEP, so that averages can be calculated
@@ -44,31 +45,34 @@
 
 // Residual heat from CO2 sensor seems to be high enough to change the temperature reading. How much should it be offset?
 // NOTE: Sign isn't relevant. The returned temperature will always be shifted down.
-#  define TEMPERATURE_OFFSET 0 // [K]
+#  define TEMPERATURE_OFFSET -3 // [K]
 
 // Altitude above sea level
 // Used for CO2 calibration
 // here: Stuttgart, Schellingstr. 24. (Source: Google Earth)
-#  define ALTITUDE_ABOVE_SEA_LEVEL 660 // [m]
+#  define ALTITUDE_ABOVE_SEA_LEVEL 600 // [m]
 
 // The reference CO2 concentration has to be within the range 400 ppm ≤ cref(CO2) ≤ 2000 ppm.
 // Used for CO2 calibration
 // here : measured concentration in Stuttgart
-#  define ATMOSPHERIC_CO2_CONCENTRATION 430 // [ppm]
+#  define ATMOSPHERIC_CO2_CONCENTRATION 425 // [ppm]
 
 // Should the sensor try to calibrate itself?
 // Sensirion recommends 7 days of continuous readings with at least 1 hour a day of 'fresh air' for self-calibration to complete.
-#  define AUTO_CALIBRATE_SENSOR false // [true / false]
+#  define AUTO_CALIBRATE_SENSOR true // [true / false]
 
 /**
  * LEDs
  */
 
 // LED brightness, which can vary between min and max brightness ("LED breathing")
-// max_brightness should be between 0 and 255.
+// MAX_BRIGHTNESS must be defined, and should be between 0 and 255.
-// min_brightness should be between 0 and max_brightness
 #  define MAX_BRIGHTNESS 128
+// MIN_BRIGHTNESS, if defined, should be between 0 and MAX_BRIGHTNESS - 1
+// If MIN_BRIGHTNESS is not set, or if it is set to MAX_BRIGHTNESS, breathing is disabled.
 #  define MIN_BRIGHTNESS 60
+// How many LEDs in the ring? 12 and 16 are currently supported. If undefined, 12 is used as default.
+#  define LED_COUNT 12
 
 /**
  * WEB SERVER
@@ -76,8 +80,8 @@
  */
 
 // Define empty strings in order to disable authentication, or remove the constants altogether.
-#  define HTTP_USER ""
+#  define HTTP_USER "co2ampel"
-#  define HTTP_PASSWORD ""
+#  define HTTP_PASSWORD "my_password"
 
 /**
  * MQTT
@@ -106,11 +110,11 @@
  */
 #  define ALLOW_MQTT_COMMANDS false
 
-// How often measurements should be sent to MQTT server?
+// How often should measurements be sent to MQTT server?
 // Probably a good idea to use a multiple of MEASUREMENT_TIMESTEP, so that averages can be calculated
 // Set to 0 if you want to send values after each measurement
-// #  define MQTT_SENDING_INTERVAL MEASUREMENT_TIMESTEP * 5 // [s]
+#  define MQTT_SENDING_INTERVAL MEASUREMENT_TIMESTEP * 5 // [s]
-#  define MQTT_SENDING_INTERVAL 60 // [s]
+//#  define MQTT_SENDING_INTERVAL 60 // [s]
 #  define MQTT_SERVER "test.mosquitto.org"  // MQTT server URL or IP address
 #  define MQTT_PORT 8883
 #  define MQTT_USER ""
@@ -149,7 +153,7 @@
  */
 
 #  define NTP_SERVER "pool.ntp.org"
-#  define UTC_OFFSET_IN_SECONDS 3600 // [s] 3600 for UTC+1
+#  define UTC_OFFSET_IN_SECONDS 7200 // [s] 3600 for UTC+1, 7200 for UTC+1 and daylight saving time
 
 /**
  * Others

ampel-firmware/csv_writer.cpp

@@ -1,14 +1,12 @@
 #include "csv_writer.h"
 
-//TODO: Allow CSV download via USB Serial, when requested (e.g. via a Python script)
-
 namespace config {
   // Values should be defined in config.h
   uint16_t csv_interval = CSV_INTERVAL; // [s]
 }
 namespace csv_writer {
   unsigned long last_written_at = 0;
-  String last_successful_write = "";
+  char last_successful_write[23];
 
 #if defined(ESP8266)
   /**
@@ -80,13 +78,16 @@ namespace csv_writer {
   }
 #endif
 
-  const String filename = "/" + SENSOR_ID + ".csv";
+  char filename[15]; // "/ESPxxxxxx.csv\0"
 
   int getAvailableSpace() {
     return getTotalSpace() - getUsedSpace();
   }
 
-  void initialize() {
+  void initialize(const char *sensorId) {
+    snprintf(filename, sizeof(filename), "/%s.csv", sensorId);
+
+    Serial.println();
     Serial.print(F("Initializing FS..."));
     if (mountFS()) {
       Serial.println(F("done."));
@@ -113,9 +114,13 @@ namespace csv_writer {
     Serial.println();
 
     // Open dir folder
-    Serial.println("Filesystem content:");
+    Serial.println(F("Filesystem content:"));
     showFilesystemContent();
     Serial.println();
+
+    sensor_console::defineIntCommand("csv", setCSVinterval, F("60 (Sets CSV writing interval, in s)"));
+    sensor_console::defineCommand("format_filesystem", formatFilesystem, F("(Deletes the whole filesystem)"));
+    sensor_console::defineCommand("show_csv", showCSVContent, F("(Displays the complete CSV file on Serial)"));
   }
 
   File openOrCreate() {
@@ -130,11 +135,11 @@ namespace csv_writer {
     return csv_file;
   }
 
-  void log(const String &timeStamp, const int16_t &co2, const float &temperature, const float &humidity) {
+  void log(const char *timestamp, const int16_t &co2, const float &temperature, const float &humidity) {
     led_effects::onBoardLEDOn();
     File csv_file = openOrCreate();
     char csv_line[42];
-    snprintf(csv_line, sizeof(csv_line), "%s;%d;%.1f;%.1f\r\n", timeStamp.c_str(), co2, temperature, humidity);
+    snprintf(csv_line, sizeof(csv_line), "%s;%d;%.1f;%.1f\r\n", timestamp, co2, temperature, humidity);
     if (csv_file) {
       size_t written_bytes = csv_file.print(csv_line);
       csv_file.close();
@@ -143,7 +148,7 @@ namespace csv_writer {
       } else {
         Serial.print(F("CSV - Wrote : "));
         Serial.print(csv_line);
-        last_successful_write = ntp::getLocalTime();
+        ntp::getLocalTime(last_successful_write);
       }
       updateFsInfo();
       delay(50);
@@ -154,11 +159,42 @@ namespace csv_writer {
     led_effects::onBoardLEDOff();
   }
 
-  void logIfTimeHasCome(const String &timeStamp, const int16_t &co2, const float &temperature, const float &humidity) {
+  void logIfTimeHasCome(const char *timeStamp, const int16_t &co2, const float &temperature, const float &humidity) {
     unsigned long now = seconds();
     if (now - last_written_at > config::csv_interval) {
       last_written_at = now;
       log(timeStamp, co2, temperature, humidity);
     }
   }
+
+  /*****************************************************************
+   * Callbacks for sensor commands                                 *
+   *****************************************************************/
+  void setCSVinterval(int32_t csv_interval) {
+    config::csv_interval = csv_interval;
+    Serial.print(F("Setting CSV Interval to : "));
+    Serial.print(config::csv_interval);
+    Serial.println("s.");
+    led_effects::showKITTWheel(color::green, 1);
+  }
+
+  void showCSVContent() {
+    Serial.print(F("### "));
+    Serial.print(filename);
+    Serial.println(F(" ###"));
+    File csv_file;
+    if (FS_LIB.exists(filename)) {
+      csv_file = FS_LIB.open(filename, "r");
+      while (csv_file.available()) {
+        Serial.write(csv_file.read());
+      }
+      csv_file.close();
+    }
+    Serial.println(F("######################"));
+  }
+
+  void formatFilesystem() {
+    FS_LIB.format();
+    led_effects::showKITTWheel(color::blue, 2);
+  }
 }

ampel-firmware/csv_writer.h

@@ -14,16 +14,21 @@
 #include "config.h"
 #include "util.h"
 #include "led_effects.h"
+#include "sensor_console.h"
 
 namespace config {
   extern uint16_t csv_interval; // [s]
 }
 namespace csv_writer {
-  extern String last_successful_write;
+  extern char last_successful_write[];
-  void initialize();
+  void initialize(const char *sensorId);
-  void logIfTimeHasCome(const String &timeStamp, const int16_t &co2, const float &temperature, const float &humidity);
+  void logIfTimeHasCome(const char *timestamp, const int16_t &co2, const float &temperature, const float &humidity);
   int getAvailableSpace();
-  extern const String filename;
+  extern char filename[];
+
+  void setCSVinterval(int32_t csv_interval);
+  void showCSVContent();
+  void formatFilesystem();
 }
 
 #endif

ampel-firmware/led_effects.cpp

@@ -4,17 +4,36 @@
  *****************************************************************/
 namespace config {
   const uint8_t max_brightness = MAX_BRIGHTNESS;
+#if defined(MIN_BRIGHTNESS)
   const uint8_t min_brightness = MIN_BRIGHTNESS;
-  const int kitt_tail = 3; // How many dimmer LEDs follow in K.I.T.T. wheel
+#else
-}
+  const uint8_t min_brightness = MAX_BRIGHTNESS;
-
+#endif
-/*****************************************************************
- * Configuration  (calculated from above values)                 *
- *****************************************************************/
-namespace config //NOTE: Use a class instead? NightMode could then be another state.
-{
   const uint8_t brightness_amplitude = config::max_brightness - config::min_brightness;
-  bool night_mode = false;
+  const int kitt_tail = 3; // How many dimmer LEDs follow in K.I.T.T. wheel
+  const uint16_t poor_air_quality_ppm = 1600; // Above this threshold, LED breathing effect is faster.
+  bool night_mode = false; //NOTE: Use a class instead? NightMode could then be another state.
+
+#if !defined(LED_COUNT)
+#  define LED_COUNT 12
+#endif
+
+  const uint16_t led_count = LED_COUNT;
+
+#if LED_COUNT == 12
+  //NOTE: One value has been prepended, to make calculations easier and avoid out of bounds index.
+  const uint16_t co2_ticks[led_count + 1] = { 0, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000, 2200 }; // [ppm]
+  // For a given LED, which color should be displayed? First LED will be pure green (hue angle 120°),
+  // LEDs >= 1600ppm will be pure red (hue angle 0°), LEDs in-between will be yellowish.
+  const uint16_t led_hues[led_count] = { 21845U, 19114U, 16383U, 13653U, 10922U, 8191U, 5461U, 2730U, 0, 0, 0, 0 }; // [hue angle]
+#elif LED_COUNT == 16
+  const uint16_t co2_ticks[led_count + 1] = { 0, 500, 600, 700, 800, 900, 1000, 1100, 1200,
+                                              1300, 1400, 1500, 1600, 1700, 1800, 2000, 2200 }; // [ppm]
+  const uint16_t led_hues[led_count] = {21845U, 19859U, 17873U, 15887U, 13901U, 11915U, 9929U, 7943U,
+                                         5957U, 3971U, 1985U, 0, 0, 0, 0, 0}; // [hue angle]
+#else
+#  error "Only 12 and 16 LEDs rings are currently supported."
+#endif
 }
 
 #if defined(ESP8266)
@@ -25,20 +44,7 @@ const int NEOPIXELS_PIN = 5;
 const int NEOPIXELS_PIN = 23;
 #endif
 
-const int NUMPIXELS = 12;
+Adafruit_NeoPixel pixels(config::led_count, NEOPIXELS_PIN, NEO_GRB + NEO_KHZ800);
-//NOTE: One value has been prepended, to make calculations easier and avoid out of bounds index.
-const uint16_t CO2_TICKS[NUMPIXELS + 1] = { 0, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000, 2200 }; // [ppm]
-// const uint16_t CO2_TICKS[NUMPIXELS + 1] = { 0, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1800, 2000, 2200 }; // [ppm]
-// For a given LED, which color should be displayed? First LED will be pure green (hue angle 120°),
-// last 4 LEDs will be pure red (hue angle 0°), LEDs in-between will be yellowish.
-// For reference, this python code can be used to generate the array
-//    NUMPIXELS = 12
-//    RED_LEDS = 4
-//    hues = [ (2**16-1) // 3 * max(NUMPIXELS - RED_LEDS - i, 0) // (NUMPIXELS - RED_LEDS) for i in range(NUMPIXELS) ]
-//    '{' + ', '.join([str(hue) + ('U' if hue else '') for hue in hues]) + '}; // [hue angle]'
-const uint16_t LED_HUES[NUMPIXELS] = { 21845U, 19114U, 16383U, 13653U, 10922U, 8191U, 5461U, 2730U, 0, 0, 0, 0 }; // [hue angle]
-// const uint16_t LED_HUES[NUMPIXELS] = { 21845U, 20024U, 18204U, 16383U, 14563U, 12742U, 10922U, 9102U, 7281U, 5461U, 3640U, 1820U, 0, 0, 0, 0 }; // [hue angle]
-Adafruit_NeoPixel pixels(NUMPIXELS, NEOPIXELS_PIN, NEO_GRB + NEO_KHZ800);
 
 namespace led_effects {
   //On-board LED on D4, aka GPIO02
@@ -71,10 +77,19 @@ namespace led_effects {
     onBoardLEDOff();
   }
 
+  void showColor(int32_t color) {
+    config::night_mode = true; // In order to avoid overwriting the desired color next time CO2 is displayed
+    pixels.setBrightness(255);
+    pixels.fill(color);
+    pixels.show();
+  }
+
   void setupRing() {
     pixels.begin();
     pixels.setBrightness(config::max_brightness);
     LEDsOff();
+    sensor_console::defineCommand("night_mode", toggleNightMode, F("(Toggles night mode on/off)"));
+    sensor_console::defineIntCommand("color", showColor, F("0xFF0015 (Shows color, specified as RGB, for debugging)"));
   }
 
   void toggleNightMode() {
@@ -89,14 +104,15 @@ namespace led_effects {
 
   //NOTE: basically one iteration of KITT wheel
   void showWaitingLED(uint32_t color) {
+    using namespace config;
     delay(80);
-    if (config::night_mode) {
+    if (night_mode) {
       return;
     }
     static uint16_t kitt_offset = 0;
     pixels.clear();
-    for (int j = config::kitt_tail; j >= 0; j--) {
+    for (int j = kitt_tail; j >= 0; j--) {
-      int ledNumber = abs((kitt_offset - j + NUMPIXELS) % (2 * NUMPIXELS) - NUMPIXELS) % NUMPIXELS; // Triangular function
+      int ledNumber = abs((kitt_offset - j + led_count) % (2 * led_count) - led_count) % led_count; // Triangular function
       pixels.setPixelColor(ledNumber, color * pixels.gamma8(255 - j * 76) / 255);
     }
     pixels.show();
@@ -108,7 +124,7 @@ namespace led_effects {
   // Takes approximately 1s for each direction.
   void showKITTWheel(uint32_t color, uint16_t duration_s) {
     pixels.setBrightness(config::max_brightness);
-    for (int i = 0; i < duration_s * NUMPIXELS; ++i) {
+    for (int i = 0; i < duration_s * config::led_count; ++i) {
       showWaitingLED(color);
     }
   }
@@ -118,10 +134,10 @@ namespace led_effects {
    * For example, for 1500ppm, every LED between 0 and 7 (500 -> 1400ppm) should be on, LED at 8 (1600ppm) should be half-on.
    */
   uint8_t getLedBrightness(uint16_t co2, int ledId) {
-    if (co2 >= CO2_TICKS[ledId + 1]) {
+    if (co2 >= config::co2_ticks[ledId + 1]) {
       return 255;
     } else {
-      if (2 * co2 >= CO2_TICKS[ledId] + CO2_TICKS[ledId + 1]) {
+      if (2 * co2 >= config::co2_ticks[ledId] + config::co2_ticks[ledId + 1]) {
         // Show partial LED if co2 more than halfway between ticks.
         return 27; // Brightness isn't linear, so 27 / 255 looks much brighter than 10%
       } else {
@@ -131,6 +147,17 @@ namespace led_effects {
     }
   }
 
+  /**
+   * If enabled, slowly varies the brightness between MAX_BRIGHTNESS & MIN_BRIGHTNESS.
+   */
+  void breathe(int16_t co2) {
+    static uint8_t breathing_offset = 0;
+    uint16_t brightness = config::min_brightness + pixels.sine8(breathing_offset) * config::brightness_amplitude / 255;
+    pixels.setBrightness(brightness);
+    pixels.show();
+    breathing_offset += co2 > config::poor_air_quality_ppm ? 6 : 3; // breathing speed. +3 looks like slow human breathing.
+  }
+
   /**
    * Fills the whole ring with green, yellow, orange or black, depending on co2 input and CO2_TICKS.
    */
@@ -139,24 +166,28 @@ namespace led_effects {
       return;
     }
     pixels.setBrightness(config::max_brightness);
-    for (int ledId = 0; ledId < NUMPIXELS; ++ledId) {
+    for (int ledId = 0; ledId < config::led_count; ++ledId) {
       uint8_t brightness = getLedBrightness(co2, ledId);
-      pixels.setPixelColor(ledId, pixels.ColorHSV(LED_HUES[ledId], 255, brightness));
+      pixels.setPixelColor(ledId, pixels.ColorHSV(config::led_hues[ledId], 255, brightness));
     }
     pixels.show();
+    if (config::brightness_amplitude > 0) {
+      breathe(co2);
+    }
   }
 
-  void showRainbowWheel(uint16_t duration_ms, uint16_t hue_increment) {
+  void showRainbowWheel(uint16_t duration_ms) {
     if (config::night_mode) {
       return;
     }
     static uint16_t wheel_offset = 0;
+    static uint16_t sine_offset = 0;
     unsigned long t0 = millis();
     pixels.setBrightness(config::max_brightness);
     while (millis() - t0 < duration_ms) {
-      for (int i = 0; i < NUMPIXELS; i++) {
+      for (int i = 0; i < config::led_count; i++) {
-        pixels.setPixelColor(i, pixels.ColorHSV(i * 65535 / NUMPIXELS + wheel_offset));
+        pixels.setPixelColor(i, pixels.ColorHSV(i * 65535 / config::led_count + wheel_offset));
-        wheel_offset += hue_increment;
+        wheel_offset += (pixels.sine8(sine_offset++ / 50) - 127) / 2;
       }
       pixels.show();
       delay(10);
@@ -179,37 +210,28 @@ namespace led_effects {
     }
   }
 
-  void breathe(int16_t co2) {
-    if (!config::night_mode) {
-      static uint16_t breathing_offset = 0;
-      uint16_t brightness = config::min_brightness
-          + pixels.sine8(breathing_offset) * config::brightness_amplitude / 255;
-      pixels.setBrightness(brightness);
-      pixels.show();
-      breathing_offset += 3; // breathing speed. +3 looks like slow human breathing.
-    }
-    delay(co2 > 1600 ? 50 : 100); // faster breathing for higher CO2 values
-  }
-
   /**
-   * Displays a complete blue circle, and starts removing LEDs one by one. Returns the number of remaining LEDs.
+   * Displays a complete blue circle, and starts removing LEDs one by one.
-   * Can be used for calibration, e.g. when countdown is 0. Does not work in night mode.
+   * Does nothing in night mode and returns false then. Returns true if
+   * the countdown has finished. Can be used for calibration, e.g. when countdown is 0.
+   * NOTE: This function is blocking and returns only after the button has
+   * been released or after every LED has been turned off.
    */
-  int countdownToZero() {
+  bool countdownToZero() {
     if (config::night_mode) {
       Serial.println(F("Night mode. Not doing anything."));
       delay(1000); // Wait for a while, to avoid coming back to this function too many times when button is pressed.
-      return 1;
+      return false;
     }
     pixels.fill(color::blue);
     pixels.show();
     int countdown;
-    for (countdown = NUMPIXELS; countdown >= 0 && !digitalRead(0); countdown--) {
+    for (countdown = config::led_count; countdown >= 0 && !digitalRead(0); countdown--) {
       pixels.setPixelColor(countdown, color::black);
       pixels.show();
       Serial.println(countdown);
       delay(500);
     }
-    return countdown;
+    return countdown < 0;
   }
 }

ampel-firmware/led_effects.h

@@ -2,6 +2,7 @@
 #define LED_EFFECTS_H_INCLUDED
 #include <Arduino.h>
 #include "config.h"
+#include "sensor_console.h"
 
 // Adafruit NeoPixel (Arduino library for controlling single-wire-based LED pixels and strip)
 // https://github.com/adafruit/Adafruit_NeoPixel
@@ -25,11 +26,10 @@ namespace led_effects {
 
   void setupRing();
   void redAlert();
-  void breathe(int16_t co2);
+  bool countdownToZero();
-  int countdownToZero();
   void showWaitingLED(uint32_t color);
   void showKITTWheel(uint32_t color, uint16_t duration_s = 2);
-  void showRainbowWheel(uint16_t duration_ms = 1000, uint16_t hue_increment = 50);
+  void showRainbowWheel(uint16_t duration_ms = 1000);
   void displayCO2color(uint16_t co2);
 }
 #endif

ampel-firmware/lorawan.cpp

@@ -33,7 +33,7 @@ void os_getDevKey(u1_t *buf) {
 namespace lorawan {
   bool waiting_for_confirmation = false;
   bool connected = false;
-  String last_transmission = "";
+  char last_transmission[23] = "";
 
   void initialize() {
     Serial.println(F("Starting LoRaWAN. Frequency plan : " LMIC_FREQUENCY_PLAN " MHz."));
@@ -47,11 +47,12 @@ namespace lorawan {
     LMIC_reset();
     // Join, but don't send anything yet.
     LMIC_startJoining();
+    sensor_console::defineIntCommand("lora", setLoRaInterval, F("300 (Sets LoRaWAN sending interval, in s)"));
   }
 
   // Checks if OTAA is connected, or if payload should be sent.
   // NOTE: while a transaction is in process (i.e. until the TXcomplete event has been received, no blocking code (e.g. delay loops etc.) are allowed, otherwise the LMIC/OS code might miss the event.
-  // If this rule is not followed, a typical symptom is that the first send is ok and all following ones end with the TX not complete failure.
+  // If this rule is not followed, a typical symptom is that the first send is ok and all following ones end with the 'TX not complete' failure.
   void process() {
     os_runloop_once();
   }
@@ -64,8 +65,10 @@ namespace lorawan {
   }
 
   void onEvent(ev_t ev) {
+    char current_time[23];
+    ntp::getLocalTime(current_time);
     Serial.print("LoRa - ");
-    Serial.print(ntp::getLocalTime());
+    Serial.print(current_time);
     Serial.print(" - ");
     switch (ev) {
     case EV_JOINING:
@@ -93,7 +96,7 @@ namespace lorawan {
           printHex2(artKey[i]);
         }
         Serial.println();
-        Serial.print("  NwkSKey: ");
+        Serial.print(F("  NwkSKey: "));
         for (size_t i = 0; i < sizeof(nwkKey); ++i) {
           if (i != 0)
             Serial.print("-");
@@ -112,7 +115,7 @@ namespace lorawan {
       Serial.println(F("EV_REJOIN_FAILED"));
       break;
     case EV_TXCOMPLETE:
-      last_transmission = ntp::getLocalTime();
+      ntp::getLocalTime(last_transmission);
       Serial.println(F("EV_TXCOMPLETE"));
       break;
     case EV_TXSTART:
@@ -189,6 +192,17 @@ namespace lorawan {
       preparePayload(co2, temperature, humidity);
     }
   }
+
+  /*****************************************************************
+   * Callbacks for sensor commands                                 *
+   *****************************************************************/
+  void setLoRaInterval(int32_t sending_interval) {
+    config::lorawan_sending_interval = sending_interval;
+    Serial.print(F("Setting LoRa sending interval to : "));
+    Serial.print(config::lorawan_sending_interval);
+    Serial.println("s.");
+    led_effects::showKITTWheel(color::green, 1);
+  }
 }
 
 void onEvent(ev_t ev) {

ampel-firmware/lorawan.h

@@ -13,7 +13,7 @@
 #include <SPI.h>
 
 #include "led_effects.h"
-
+#include "sensor_console.h"
 #include "util.h"
 
 namespace config {
@@ -39,10 +39,12 @@ namespace config {
 namespace lorawan {
   extern bool waiting_for_confirmation;
   extern bool connected;
-  extern String last_transmission;
+  extern char last_transmission[];
   void initialize();
   void process();
   void preparePayloadIfTimeHasCome(const int16_t &co2, const float &temp, const float &hum);
+
+  void setLoRaInterval(int32_t sending_interval);
 }
 
 #endif

ampel-firmware/mqtt.cpp

@@ -2,7 +2,7 @@
 
 namespace config {
   // Values should be defined in config.h
-  uint16_t sending_interval = MQTT_SENDING_INTERVAL; // [s]
+  uint16_t mqtt_sending_interval = MQTT_SENDING_INTERVAL; // [s]
   //INFO: Listen to every CO2 sensor which is connected to the server:
   //  mosquitto_sub -h MQTT_SERVER -t 'CO2sensors/#' -p 443 --capath /etc/ssl/certs/ -u "MQTT_USER" -P "MQTT_PASSWORD" -v
   const char *mqtt_server = MQTT_SERVER;
@@ -23,31 +23,34 @@ namespace mqtt {
   unsigned long last_failed_at = 0;
   bool connected = false;
 
-  String publish_topic;
+  char publish_topic[21]; // e.g. "CO2sensors/ESPxxxxxx\0"
   const char *json_sensor_format;
-  String last_successful_publish = "";
+  char last_successful_publish[23] = "";
 
-  void initialize(String &topic) {
+  void initialize(const char *sensorId) {
     json_sensor_format = PSTR("{\"time\":\"%s\", \"co2\":%d, \"temp\":%.1f, \"rh\":%.1f}");
-    publish_topic = topic;
+    snprintf(publish_topic, sizeof(publish_topic), "CO2sensors/%s", sensorId);
-#if defined(ESP8266)
+    // The sensor doesn't check the fingerprint of the MQTT broker, because otherwise this fingerprint should be updated
-    espClient.setInsecure(); // Sorry, we don't want to flash the sensors every 3 months.
+    // on the sensor every 3 months. The connection can still be encrypted, though:
-#endif
+    espClient.setInsecure(); // If not available for ESP32, please update Arduino IDE / PlatformIO
-    // mqttClient.setSocketTimeout(config::mqtt_timeout); //NOTE: somehow doesn't seem to have any effect on connect()
     mqttClient.setServer(config::mqtt_server, config::mqtt_port);
+
+    sensor_console::defineIntCommand("mqtt", setMQTTinterval, F("60 (Sets MQTT sending interval, in s)"));
+    sensor_console::defineCommand("send_local_ip", sendInfoAboutLocalNetwork,
+        F("(Sends local IP and SSID via MQTT. Can be useful to find sensor)"));
   }
 
-  void publish(const String &timestamp, int16_t co2, float temperature, float humidity) {
+  void publish(const char *timestamp, int16_t co2, float temperature, float humidity) {
     if (WiFi.status() == WL_CONNECTED && mqttClient.connected()) {
       led_effects::onBoardLEDOn();
       Serial.print(F("MQTT - Publishing message ... "));
 
       char payload[75]; // Should be enough for json...
-      snprintf(payload, sizeof(payload), json_sensor_format, timestamp.c_str(), co2, temperature, humidity);
+      snprintf(payload, sizeof(payload), json_sensor_format, timestamp, co2, temperature, humidity);
       // Topic is the same as clientID. e.g. 'CO2sensors/ESP3d03da'
-      if (mqttClient.publish(publish_topic.c_str(), payload)) {
+      if (mqttClient.publish(publish_topic, payload)) {
         Serial.println(F("OK"));
-        last_successful_publish = ntp::getLocalTime();
+        ntp::getLocalTime(last_successful_publish);
       } else {
         Serial.println(F("Failed."));
       }
@@ -55,69 +58,6 @@ namespace mqtt {
     }
   }
 
-  void setTimer(String messageString) {
-    messageString.replace("timer ", "");
-    int timestep = messageString.toInt();
-    if (timestep >= 2 && timestep <= 1800) {
-      Serial.print(F("Setting Measurement Interval to : "));
-      Serial.print(timestep);
-      Serial.println("s.");
-      sensor::scd30.setMeasurementInterval(messageString.toInt());
-      config::measurement_timestep = messageString.toInt();
-      led_effects::showKITTWheel(color::green, 1);
-    }
-  }
-
-  void setMQTTinterval(String messageString) {
-    messageString.replace("mqtt ", "");
-    config::sending_interval = messageString.toInt();
-    Serial.print(F("Setting Sending Interval to : "));
-    Serial.print(config::sending_interval);
-    Serial.println("s.");
-    led_effects::showKITTWheel(color::green, 1);
-  }
-
-#ifdef AMPEL_CSV
-  void setCSVinterval(String messageString) {
-    messageString.replace("csv ", "");
-    config::csv_interval = messageString.toInt();
-    Serial.print(F("Setting CSV Interval to : "));
-    Serial.print(config::csv_interval);
-    Serial.println("s.");
-    led_effects::showKITTWheel(color::green, 1);
-  }
-#endif
-
-  void calibrateSensorToSpecificPPM(String messageString) {
-    messageString.replace("calibrate ", "");
-    long int calibrationLevel = messageString.toInt();
-    if (calibrationLevel >= 400 && calibrationLevel <= 2000) {
-      Serial.print(F("Force calibration, at "));
-      config::co2_calibration_level = messageString.toInt();
-      Serial.print(config::co2_calibration_level);
-      Serial.println(" ppm.");
-      sensor::startCalibrationProcess();
-    }
-  }
-
-  void setCO2forDebugging(String messageString) {
-    Serial.print(F("DEBUG. Setting CO2 to "));
-    messageString.replace("co2 ", "");
-    sensor::co2 = messageString.toInt();
-    Serial.println(sensor::co2);
-  }
-
-  void sendInfoAboutLocalNetwork() {
-    char info_topic[60]; // Should be enough for "CO2sensors/ESPd03cc5/info"
-    snprintf(info_topic, sizeof(info_topic), "%s/info", publish_topic.c_str());
-
-    char payload[75]; // Should be enough for info json...
-    const char *json_info_format = PSTR("{\"local_ip\":\"%s\", \"ssid\":\"%s\"}");
-    snprintf(payload, sizeof(payload), json_info_format, WiFi.localIP().toString().c_str(), WiFi.SSID().c_str());
-
-    mqttClient.publish(info_topic, payload);
-  }
-
   /**
    * Allows sensor to be controlled by commands over MQTT
    *
@@ -132,46 +72,13 @@ namespace mqtt {
     }
     led_effects::onBoardLEDOn();
     Serial.print(F("Message arrived on topic: "));
-    Serial.print(sub_topic);
+    Serial.println(sub_topic);
-    Serial.print(F(". Message: '"));
+    char command[length + 1];
-    String messageString;
     for (unsigned int i = 0; i < length; i++) {
-      Serial.print((char) message[i]);
+      command[i] = message[i];
-      messageString += (char) message[i];
     }
-    Serial.println("'.");
+    command[length] = 0;
-
+    sensor_console::execute(command);
-    if (messageString.startsWith("co2 ")) {
-      setCO2forDebugging(messageString);
-    } else if (messageString.startsWith("timer ")) {
-      setTimer(messageString);
-    } else if (messageString == "calibrate") {
-      sensor::startCalibrationProcess();
-    } else if (messageString.startsWith("calibrate ")) {
-      calibrateSensorToSpecificPPM(messageString);
-    } else if (messageString.startsWith("mqtt ")) {
-      setMQTTinterval(messageString);
-    } else if (messageString == "publish") {
-      Serial.println(F("Forcing MQTT publish now."));
-      publish(sensor::timestamp, sensor::co2, sensor::temperature, sensor::humidity);
-#ifdef AMPEL_CSV
-    } else if (messageString.startsWith("csv ")) {
-      setCSVinterval(messageString);
-    } else if (messageString == "format_filesystem") {
-      FS_LIB.format();
-      led_effects::showKITTWheel(color::blue, 2);
-#endif
-    } else if (messageString == "night_mode") {
-      led_effects::toggleNightMode();
-    } else if (messageString == "local_ip") {
-      sendInfoAboutLocalNetwork();
-    } else if (messageString == "reset") {
-      ESP.restart(); // softer than ESP.reset()
-    } else {
-      led_effects::showKITTWheel(color::red, 1);
-      Serial.println(F("Message not supported. Doing nothing."));
-    }
-    delay(50);
     led_effects::onBoardLEDOff();
   }
 
@@ -188,7 +95,7 @@ namespace mqtt {
 
     led_effects::onBoardLEDOn();
     // Wait for connection, at most 15s (default)
-    mqttClient.connect(publish_topic.c_str(), config::mqtt_user, config::mqtt_password);
+    mqttClient.connect(publish_topic, config::mqtt_user, config::mqtt_password);
     led_effects::onBoardLEDOff();
 
     connected = mqttClient.connected();
@@ -196,7 +103,7 @@ namespace mqtt {
     if (connected) {
       if (config::allow_mqtt_commands) {
         char control_topic[60]; // Should be enough for "CO2sensors/ESPd03cc5/control"
-        snprintf(control_topic, sizeof(control_topic), "%s/control", publish_topic.c_str());
+        snprintf(control_topic, sizeof(control_topic), "%s/control", publish_topic);
         mqttClient.subscribe(control_topic);
         mqttClient.setCallback(controlSensorCallback);
       }
@@ -212,12 +119,12 @@ namespace mqtt {
     }
   }
 
-  void publishIfTimeHasCome(const String &timeStamp, const int16_t &co2, const float &temp, const float &hum) {
+  void publishIfTimeHasCome(const char *timestamp, const int16_t &co2, const float &temp, const float &hum) {
     // Send message via MQTT according to sending interval
     unsigned long now = seconds();
-    if (now - last_sent_at > config::sending_interval) {
+    if (now - last_sent_at > config::mqtt_sending_interval) {
       last_sent_at = now;
-      publish(timeStamp, co2, temp, hum);
+      publish(timestamp, co2, temp, hum);
     }
   }
 
@@ -229,4 +136,28 @@ namespace mqtt {
     mqttClient.loop();
   }
 
+  /*****************************************************************
+   * Callbacks for sensor commands                                 *
+   *****************************************************************/
+  void setMQTTinterval(int32_t sending_interval) {
+    config::mqtt_sending_interval = sending_interval;
+    Serial.print(F("Setting MQTT sending interval to : "));
+    Serial.print(config::mqtt_sending_interval);
+    Serial.println("s.");
+    led_effects::showKITTWheel(color::green, 1);
+  }
+
+  // It can be hard to find the local IP of a sensor if it isn't connected to Serial port, and if mDNS is disabled.
+  // If the sensor can be reach by MQTT, it can answer with info about local_ip and ssid.
+  // The sensor will send the info to "CO2sensors/ESP123456/info".
+  void sendInfoAboutLocalNetwork() {
+    char info_topic[60]; // Should be enough for "CO2sensors/ESP123456/info"
+    snprintf(info_topic, sizeof(info_topic), "%s/info", publish_topic);
+
+    char payload[75]; // Should be enough for info json...
+    const char *json_info_format = PSTR("{\"local_ip\":\"%s\", \"ssid\":\"%s\"}");
+    snprintf(payload, sizeof(payload), json_info_format, wifi::local_ip, WIFI_SSID);
+
+    mqttClient.publish(info_topic, payload);
+  }
 }

ampel-firmware/mqtt.h

@@ -4,20 +4,22 @@
 #include <Arduino.h>
 #include "config.h"
 #include "led_effects.h"
-#ifdef AMPEL_CSV
+#include "sensor_console.h"
-#  include "csv_writer.h"
-#endif
-#include "co2_sensor.h"
 #include "src/lib/PubSubClient/src/PubSubClient.h"
 #include "wifi_util.h"
+
 namespace config {
-  extern uint16_t sending_interval; // [s]
+  extern uint16_t mqtt_sending_interval; // [s]
 }
+
 namespace mqtt {
-  extern String last_successful_publish;
+  extern char last_successful_publish[];
   extern bool connected;
-  void initialize(String &topic);
+  void initialize(const char *sensorId);
   void keepConnection();
-  void publishIfTimeHasCome(const String &timeStamp, const int16_t &co2, const float &temp, const float &hum);
+  void publishIfTimeHasCome(const char *timestamp, const int16_t &co2, const float &temp, const float &hum);
+
+  void setMQTTinterval(int32_t sending_interval);
+  void sendInfoAboutLocalNetwork();
 }
 #endif

ampel-firmware/sensor_console.cpp

@@ -0,0 +1,188 @@
+#include "sensor_console.h"
+
+namespace sensor_console {
+  const uint8_t MAX_COMMANDS = 20;
+  const uint8_t MAX_COMMAND_SIZE = 30;
+
+  uint8_t commands_count = 0;
+
+  enum input_type {
+    NONE,
+    INT32,
+    STRING
+  };
+
+  struct Command {
+    const char *name;
+    union {
+      void (*voidFunction)();
+      void (*intFunction)(int32_t);
+      void (*strFunction)(char*);
+    };
+    const char *doc;
+    input_type parameter_type;
+  };
+
+  struct CommandLine {
+    char function_name[MAX_COMMAND_SIZE];
+    input_type argument_type;
+    int32_t int_argument;
+    char str_argument[MAX_COMMAND_SIZE];
+  };
+
+  Command commands[MAX_COMMANDS];
+
+  bool addCommand(const char *name, const __FlashStringHelper *doc_fstring) {
+    if (commands_count < MAX_COMMANDS) {
+      commands[commands_count].name = name;
+      commands[commands_count].doc = (const char*) doc_fstring;
+      return true;
+    } else {
+      Serial.println(F("Too many commands have been defined."));
+      return false;
+    }
+  }
+
+  void defineCommand(const char *name, void (*function)(), const __FlashStringHelper *doc_fstring) {
+    if (addCommand(name, doc_fstring)) {
+      commands[commands_count].voidFunction = function;
+      commands[commands_count++].parameter_type = NONE;
+    }
+  }
+
+  void defineIntCommand(const char *name, void (*function)(int32_t), const __FlashStringHelper *doc_fstring) {
+    if (addCommand(name, doc_fstring)) {
+      commands[commands_count].intFunction = function;
+      commands[commands_count++].parameter_type = INT32;
+    }
+  }
+
+  void defineStringCommand(const char *name, void (*function)(char*), const __FlashStringHelper *doc_fstring) {
+    if (addCommand(name, doc_fstring)) {
+      commands[commands_count].strFunction = function;
+      commands[commands_count++].parameter_type = STRING;
+    }
+  }
+
+  /*
+   * Tries to split a string command (e.g. 'mqtt 60' or 'show_csv') into
+   * a CommandLine struct (function_name, argument_type and argument)
+   */
+  void parseCommand(const char *command, CommandLine &command_line) {
+    if (strlen(command) == 0) {
+      Serial.println(F("Received empty command"));
+      command_line.argument_type = NONE;
+      return;
+    }
+
+    char *first_space;
+    first_space = strchr(command, ' ');
+
+    if (first_space == NULL) {
+      command_line.argument_type = NONE;
+      strlcpy(command_line.function_name, command, MAX_COMMAND_SIZE);
+      return;
+    }
+
+    strlcpy(command_line.function_name, command, first_space - command + 1);
+    strlcpy(command_line.str_argument, first_space + 1, MAX_COMMAND_SIZE - (first_space - command) - 1);
+
+    char *end;
+    command_line.int_argument = strtol(command_line.str_argument, &end, 0); // Accepts 123 or 0xFF00FF
+
+    if (*end) {
+      command_line.argument_type = STRING;
+    } else {
+      command_line.argument_type = INT32;
+    }
+  }
+
+  int compareCommandNames(const void *s1, const void *s2) {
+    struct Command *c1 = (struct Command*) s1;
+    struct Command *c2 = (struct Command*) s2;
+    return strcmp(c1->name, c2->name);
+  }
+
+  void listAvailableCommands() {
+    qsort(commands, commands_count, sizeof(commands[0]), compareCommandNames);
+    for (uint8_t i = 0; i < commands_count; i++) {
+      Serial.print(F("  "));
+      Serial.print(commands[i].name);
+      Serial.print(F(" "));
+      Serial.print(commands[i].doc);
+      Serial.println(F("."));
+    }
+  }
+
+  /*
+   * Saves bytes from Serial.read() until enter is pressed, and tries to run the corresponding command.
+   *   http://www.gammon.com.au/serial
+   */
+  void processSerialInput(const byte input_byte) {
+    static char input_line[MAX_COMMAND_SIZE];
+    static unsigned int input_pos = 0;
+    switch (input_byte) {
+    case '\n': // end of text
+      Serial.println();
+      input_line[input_pos] = 0;
+      execute(input_line);
+      input_pos = 0;
+      break;
+    case '\r': // discard carriage return
+      break;
+    case '\b': // backspace
+      if (input_pos > 0) {
+        input_pos--;
+        Serial.print(F("\b \b"));
+      }
+      break;
+    default:
+      if (input_pos == 0) {
+        Serial.print(F("> "));
+      }
+      // keep adding if not full ... allow for terminating null byte
+      if (input_pos < (MAX_COMMAND_SIZE - 1)) {
+        input_line[input_pos++] = input_byte;
+        Serial.print((char) input_byte);
+      }
+      break;
+    }
+  }
+
+  /*
+   * Tries to find the corresponding callback for a given command. Name and parameter type should fit.
+   */
+  void execute(const char *command_str) {
+    CommandLine input;
+    parseCommand(command_str, input);
+    for (uint8_t i = 0; i < commands_count; i++) {
+      if (!strcmp(input.function_name, commands[i].name) && input.argument_type == commands[i].parameter_type) {
+        Serial.print(F("Calling : "));
+        Serial.print(input.function_name);
+        switch (input.argument_type) {
+        case NONE:
+          Serial.println(F("()"));
+          commands[i].voidFunction();
+          return;
+        case INT32:
+          Serial.print(F("("));
+          Serial.print(input.int_argument);
+          Serial.println(F(")"));
+          commands[i].intFunction(input.int_argument);
+          return;
+        case STRING:
+          Serial.print(F("('"));
+          Serial.print(input.str_argument);
+          Serial.println(F("')"));
+          commands[i].strFunction(input.str_argument);
+          return;
+        }
+      }
+    }
+    Serial.print(F("'"));
+    Serial.print(command_str);
+    Serial.println(F("' not supported. Available commands :"));
+    listAvailableCommands();
+  }
+
+}

ampel-firmware/sensor_console.h

@@ -0,0 +1,20 @@
+#ifndef SENSOR_CONSOLE_H_INCLUDED
+#define SENSOR_CONSOLE_H_INCLUDED
+#include <Arduino.h>
+
+/** Other scripts can use this namespace, in order to define commands, via callbacks.
+ * Those callbacks can then be used to send commands to the sensor (reset, calibrate, night mode, ...)
+ * The callbacks can either have no parameter, or one int32_t parameter.
+ */
+
+namespace sensor_console {
+  void defineCommand(const char *name, void (*function)(), const __FlashStringHelper *doc_fstring);
+  void defineIntCommand(const char *name, void (*function)(int32_t), const __FlashStringHelper *doc_fstring);
+  void defineStringCommand(const char *name, void (*function)(char*), const __FlashStringHelper *doc_fstring);
+
+  void processSerialInput(const byte in_byte);
+
+  void execute(const char *command_line);
+}
+
+#endif

ampel-firmware/src/lib/NTPClient-master/NTPClient.cpp

@@ -152,19 +152,17 @@ int NTPClient::getSeconds() {
   return (this->getEpochTime() % 60);
 }
 
-String NTPClient::getFormattedTime(unsigned long secs) {
+void NTPClient::getFormattedTime(char *formatted_time, unsigned long secs) {
   unsigned long rawTime = secs ? secs : this->getEpochTime();
   unsigned int hours = (rawTime % 86400L) / 3600;
   unsigned int minutes = (rawTime % 3600) / 60;
   unsigned int seconds = rawTime % 60;
 
-  char formatted_time[9];
+  snprintf(formatted_time, 9, "%02d:%02d:%02d", hours, minutes, seconds);
-  snprintf(formatted_time, sizeof(formatted_time), "%02d:%02d:%02d", hours, minutes, seconds);
-  return String(formatted_time);
 }
 
 // Based on https://github.com/PaulStoffregen/Time/blob/master/Time.cpp
-String NTPClient::getFormattedDate(unsigned long secs) {
+void NTPClient::getFormattedDate(char *formatted_date, unsigned long secs) {
   unsigned long rawTime = (secs ? secs : this->getEpochTime()) / 86400L;  // in days
   unsigned long days = 0, year = 1970;
   uint8_t month;
@@ -187,11 +185,9 @@ String NTPClient::getFormattedDate(unsigned long secs) {
   month++; // jan is month 1
   rawTime++; // first day is day 1
 
-  char formatted_date[23];
+  char formatted_time[9];
-  snprintf(formatted_date, sizeof(formatted_date), "%4lu-%02d-%02lu %s%+03d",
+  this->getFormattedTime(formatted_time, secs);
-      year, month, rawTime, this->getFormattedTime(secs).c_str(), this->_timeOffset / 3600);
+  snprintf(formatted_date, 23, "%4lu-%02d-%02lu %s%+03d", year, month, rawTime, formatted_time, this->_timeOffset / 3600);
-
-  return String(formatted_date);
 }
 
 void NTPClient::end() {

ampel-firmware/src/lib/NTPClient-master/NTPClient.h

@@ -80,7 +80,7 @@ class NTPClient {
     /**
     * @return secs argument (or 0 for current time) formatted like `hh:mm:ss`
     */
-    String getFormattedTime(unsigned long secs = 0);
+    void getFormattedTime(char *formatted_time, unsigned long secs = 0);
 
     /**
      * @return time in seconds since Jan. 1, 1970
@@ -91,7 +91,7 @@ class NTPClient {
     * @return secs argument (or 0 for current date) formatted to ISO 8601
     * like `2004-02-12T15:19:21+00:00`
     */
-    String getFormattedDate(unsigned long secs = 0);
+    void getFormattedDate(char *formatted_date, unsigned long secs = 0);
 
     /**
      * Stops the underlying UDP client

ampel-firmware/src/lib/SparkFun_SCD30_Arduino_Library/LICENSE.md

@@ -34,7 +34,7 @@ Code
 
 The MIT License (MIT)
 
-Copyright (c) 2016 SparkFun Electronics
+Copyright (c) 2020 SparkFun Electronics
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

ampel-firmware/src/lib/SparkFun_SCD30_Arduino_Library/README.md

@@ -24,6 +24,7 @@ Thanks to!
 * [awatterott](https://github.com/awatterott) for adding [getAltitudeCompensation()](https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library/pull/18)
 * [jogi-k](https://github.com/jogi-k) for adding [teensy i2clib](https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library/pull/19) support
 * [paulvha](https://github.com/paulvha) for the suggestions and corrections in [his version of the library](https://github.com/paulvha/scd30)
+* [yamamaya](https://github.com/yamamaya) for the [3ms delay](https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library/pull/24)
 
 Repository Contents
 -------------------
@@ -43,8 +44,6 @@ License Information
 
 This product is _**open source**_!
 
-Various bits of the code have different licenses applied. Anything SparkFun wrote is beerware; if you see me (or any other SparkFun employee) at the local, and you've found our code helpful, please buy us a round!
-
 Please use, reuse, and modify these files as you see fit. Please maintain attribution to SparkFun Electronics and release anything derivative under the same license.
 
 Distributed as-is; no warranty is given.

ampel-firmware/src/lib/SparkFun_SCD30_Arduino_Library/library.properties

@@ -1,5 +1,5 @@
 name=SparkFun SCD30 Arduino Library
-version=1.0.11
+version=1.0.13
 author=SparkFun Electronics
 maintainer=SparkFun Electronics <sparkfun.com>
 sentence=Library for the Sensirion SCD30 CO2 Sensor

ampel-firmware/src/lib/SparkFun_SCD30_Arduino_Library/src/SparkFun_SCD30_Arduino_Library.cpp

@@ -266,6 +266,8 @@ bool SCD30::readMeasurement()
   if (_i2cPort->endTransmission() != 0)
     return (0); //Sensor did not ACK
 
+  delay(3);
+
   const uint8_t receivedBytes = _i2cPort->requestFrom((uint8_t)SCD30_ADDRESS, (uint8_t)18);
   bool error = false;
   if (_i2cPort->available())
@@ -358,6 +360,8 @@ bool SCD30::getSettingValue(uint16_t registerAddress, uint16_t *val)
   if (_i2cPort->endTransmission() != 0)
     return (false); //Sensor did not ACK
 
+  delay(3);
+
   _i2cPort->requestFrom((uint8_t)SCD30_ADDRESS, (uint8_t)3); // Request data and CRC
   if (_i2cPort->available())
   {
@@ -389,6 +393,8 @@ uint16_t SCD30::readRegister(uint16_t registerAddress)
   if (_i2cPort->endTransmission() != 0)
     return (0); //Sensor did not ACK
 
+  delay(3);
+
   _i2cPort->requestFrom((uint8_t)SCD30_ADDRESS, (uint8_t)2);
   if (_i2cPort->available())
   {

ampel-firmware/src/lib/SparkFun_SCD30_Arduino_Library/src/SparkFun_SCD30_Arduino_Library.h

@@ -57,7 +57,8 @@
 #define COMMAND_STOP_MEAS 0x0104
 #define COMMAND_READ_FW_VER 0xD100
 
-typedef union {
+typedef union
+{
 	byte array[4];
 	float value;
 } ByteToFl; // paulvha
@@ -69,9 +70,9 @@ public:
 
 	bool begin(bool autoCalibrate) { return begin(Wire, autoCalibrate); }
 #ifdef USE_TEENSY3_I2C_LIB
-	bool begin(i2c_t3 &wirePort = Wire, bool autoCalibrate=true, bool measBegin=true); //By default use Wire port
+	bool begin(i2c_t3 &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); //By default use Wire port
 #else
-	bool begin(TwoWire &wirePort = Wire, bool autoCalibrate=true, bool measBegin=true); //By default use Wire port
+	bool begin(TwoWire &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); //By default use Wire port
 #endif
 
 	void enableDebugging(Stream &debugPort = Serial); //Turn on debug printing. If user doesn't specify then Serial will be used.
@@ -115,7 +116,6 @@ public:
 	uint8_t computeCRC8(uint8_t data[], uint8_t len);
 
 private:
-
 	//Variables
 #ifdef USE_TEENSY3_I2C_LIB
 	i2c_t3 *_i2cPort; //The generic connection to user's chosen I2C hardware
@@ -136,6 +136,5 @@ private:
 	//Debug
 	Stream *_debugPort;			 //The stream to send debug messages to if enabled. Usually Serial.
 	boolean _printDebug = false; //Flag to print debugging variables
-
 };
 #endif

ampel-firmware/util.cpp

@@ -5,41 +5,96 @@ namespace config {
   const long utc_offset_in_seconds = UTC_OFFSET_IN_SECONDS; // UTC+1
 }
 
-// Get last 3 bytes of ESP MAC (worldwide unique)
+#if defined(ESP8266)
-String macToID() {
+const char *current_board = "ESP8266";
-  uint8_t mac[6];
+#  if !defined(AMPEL_WIFI)
-  WiFi.macAddress(mac);
+void preinit() {
-  String result;
+  // WiFi would be initialized otherwise (on ESP8266), even if unused.
-  for (int i = 3; i < 6; i++) {
+  // see https://github.com/esp8266/Arduino/issues/2111#issuecomment-224251391
-    if (mac[i] < 16)
+  ESP8266WiFiClass::preinitWiFiOff();
-      result += '0';
-    result += String(mac[i], HEX);
-  }
-  result.toLowerCase();
-  return result;
 }
+#  endif
+#elif defined(ESP32)
+const char *current_board = "ESP32";
+#else
+const char *current_board = "UNKNOWN";
+#endif
 
 //NOTE: ESP32 sometimes couldn't access the NTP server, and every loop would take +1000ms
 // ifdefs could be used to define functions specific to ESP32, e.g. with configTime
 namespace ntp {
   WiFiUDP ntpUDP;
   NTPClient timeClient(ntpUDP, config::ntp_server, config::utc_offset_in_seconds, 60000UL);
+  bool connected_at_least_once = false;
 
   void initialize() {
     timeClient.begin();
   }
 
   void update() {
-    timeClient.update();
+    connected_at_least_once |= timeClient.update();
   }
 
-  String getLocalTime() {
+  void getLocalTime(char *timestamp) {
-    return timeClient.getFormattedDate();
+    timeClient.getFormattedDate(timestamp);
+  }
+
+  void setLocalTime(int32_t unix_seconds) {
+    char time[23];
+    timeClient.getFormattedDate(time);
+    Serial.print(F("Current time : "));
+    Serial.println(time);
+    if (connected_at_least_once) {
+      Serial.println(F("NTP update already happened. Not changing anything."));
+      return;
+    }
+    Serial.print(F("Setting UNIX time to : "));
+    Serial.println(unix_seconds);
+    timeClient.setEpochTime(unix_seconds - seconds());
+    timeClient.getFormattedDate(time);
+    Serial.print(F("Current time : "));
+    Serial.println(time);
   }
 }
 
-uint32_t max_loop_duration = 0;
+void Ampel::showFreeSpace() {
+  Serial.print(F("Free heap space : "));
+  Serial.print(ESP.getFreeHeap());
+  Serial.println(F(" bytes."));
+  Serial.print(F("Max free block size : "));
+  Serial.print(esp_get_max_free_block_size());
+  Serial.println(F(" bytes."));
+  Serial.print(F("Heap fragmentation : "));
+  Serial.print(esp_get_heap_fragmentation());
+  Serial.println(F(" %"));
+}
 
-//FIXME: Remove every instance of Strings, to avoid heap fragmentation problems. (Start:  "Free heap space : 17104 bytes")
+char sensorId[10]; // e.g "ESPxxxxxx\0"
-// See more https://cpp4arduino.com/2020/02/07/how-to-format-strings-without-the-string-class.html
+char macAddress[18]; // e.g "XX:XX:XX:XX:XX:XX\0"
-const String SENSOR_ID = "ESP" + macToID();
+uint8_t mac[6];
+
+char* getMacString() {
+  WiFi.macAddress(mac);
+  // Get all 6 bytes of ESP MAC
+  snprintf(macAddress, sizeof(macAddress), "%02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4],
+      mac[5]);
+  return macAddress;
+}
+
+char* getSensorId() {
+  WiFi.macAddress(mac);
+  // Get last 3 bytes of ESP MAC (worldwide unique)
+  snprintf(sensorId, sizeof(sensorId), "ESP%02x%02x%02x", mac[3], mac[4], mac[5]);
+  return sensorId;
+}
+
+Ampel::Ampel() :
+    board(current_board), sensorId(getSensorId()), macAddress(getMacString()), max_loop_duration(0) {
+  sensor_console::defineIntCommand("set_time", ntp::setLocalTime, F("1618829570 (Sets time to the given UNIX time)"));
+  sensor_console::defineCommand("free", Ampel::showFreeSpace, F("(Displays available heap space)"));
+  sensor_console::defineCommand("reset", []() {
+    ESP.restart();
+  }, F("(Restarts the ESP)"));
+}
+
+Ampel ampel;

ampel-firmware/util.h

@@ -2,26 +2,25 @@
 #define AMPEL_UTIL_H_INCLUDED
 #include <Arduino.h>
 #include "config.h"
+#include "sensor_console.h"
 
 #include <WiFiUdp.h> // required for NTP
 #include "src/lib/NTPClient-master/NTPClient.h" // NTP
 
 #if defined(ESP8266)
-#  define BOARD "ESP8266"
 #  include <ESP8266WiFi.h> // required to get MAC address
-#  define get_free_heap_size() system_get_free_heap_size()
+#  define esp_get_max_free_block_size() ESP.getMaxFreeBlockSize()
+#  define esp_get_heap_fragmentation() ESP.getHeapFragmentation()
 #elif defined(ESP32)
-#  define BOARD "ESP32"
 #  include <WiFi.h> // required to get MAC address
-#  define get_free_heap_size() esp_get_free_heap_size()
+#  define esp_get_max_free_block_size() ESP.getMaxAllocHeap() //largest block of heap that can be allocated.
-#else
+#  define esp_get_heap_fragmentation() "?" // apparently not available for ESP32
-#  define BOARD "Unknown"
 #endif
 
 namespace ntp {
   void initialize();
   void update();
-  String getLocalTime();
+  void getLocalTime(char *timestamp);
 }
 
 namespace util {
@@ -35,10 +34,21 @@ namespace util {
     return b > a ? b : a;
   }
 }
+class Ampel {
+private:
+  static void showFreeSpace();
+public:
+  const char *version = "v0.2.3-DEV"; // Update manually after significant changes.
+  const char *board;
+  const char *sensorId;
+  const char *macAddress;
+  uint32_t max_loop_duration;
+  Ampel();
+};
+
+extern Ampel ampel;
 
 //NOTE: Only use seconds() for duration comparison, not timestamps comparison. Otherwise, problems happen when millis roll over.
 #define seconds() (millis() / 1000UL)
-extern uint32_t max_loop_duration;
-const extern String SENSOR_ID;
 
 #endif

ampel-firmware/web_server.cpp

@@ -22,6 +22,7 @@ namespace web_server {
   const char *script_template;
   void handleWebServerRoot();
   void handlePageNotFound();
+  void handleWebServerCommand();
 
 #ifdef AMPEL_CSV
   void handleDeleteCSV();
@@ -58,13 +59,13 @@ namespace web_server {
             "</head>\n"
             "<body>\n"
 
-            "<div class='pure-g'><div class='pure-u-1'><div class='pure-menu'><p class='pure-menu-heading'>MakerLab Murnau e.V. CO<sub>2</sub> Ampel</p></div></div>\n"
+            "<div class='pure-g'><div class='pure-u-1'><div class='pure-menu'><p class='pure-menu-heading'>HfT-Stuttgart CO<sub>2</sub> Ampel</p></div></div>\n"
             "<div class='pure-u-1'><ul class='pure-menu pure-menu-horizontal pure-menu-list'>\n"
             "<li class='pure-menu-item'><a href='#table' class='pure-menu-link'>Info</a></li>\n"
 #ifdef AMPEL_CSV
             "<li class='pure-menu-item'><a href='#graph' class='pure-menu-link'>Graph</a></li>\n"
             "<li class='pure-menu-item'><a href='#log' class='pure-menu-link'>Log</a></li>\n"
-            "<li class='pure-menu-item'><a href='./%s' class='pure-menu-link'>Download CSV</a></li>\n"
+            "<li class='pure-menu-item'><a href='%s' class='pure-menu-link'>Download CSV</a></li>\n"
 #endif
             "<li class='pure-menu-item' id='led'>&#11044;</li>\n" // LED
             "</ul></div></div>\n"
@@ -72,16 +73,15 @@ namespace web_server {
             // Show a colored dot on the webpage, with a similar color than on LED Ring.
             "hue=(1-(Math.min(Math.max(parseInt(document.title),500),1600)-500)/1100)*120;\n"
             "document.getElementById('led').style.color=['hsl(',hue,',100%%,50%%)'].join('');\n"
-            "</script>\n");
+            "</script>\n"
-
+            "<div class='pure-g'>\n"
-    body_template =
-        PSTR("<div class='pure-g'>\n"
             "<div class='pure-u-1' id='graph'></div>\n"// Graph placeholder
             "</div>\n"
             "<div class='pure-g'>\n"
-            //Sensor table
+            "<table id='table' class='pure-table-striped pure-u-1 pure-u-md-1-2'>\n");
-            "<table id='table' class='pure-table-striped pure-u-1 pure-u-md-1-2'>\n"
+
-            "<tr><th colspan='2'>%s</th></tr>\n"
+    body_template =
+        PSTR("<tr><th colspan='2'>%s</th></tr>\n"
             "<tr><td>CO<sub>2</sub> concentration</td><td>%5d ppm</td></tr>\n"
             "<tr><td>Temperature</td><td>%.1f&#8451;</td></tr>\n"
             "<tr><td>Humidity</td><td>%.1f%%</td></tr>\n"
@@ -108,14 +108,19 @@ namespace web_server {
 #endif
             "<tr><th colspan='2'>Sensor</th></tr>\n"
             "<tr><td>Temperature offset</td><td>%.1fK</td></tr>\n" //TODO: Read it from sensor?
+            "<tr><td>Auto-calibration?</td><td>%s</td></tr>\n"
             "<tr><td>Local address</td><td><a href='http://%s.local/'>%s.local</a></td></tr>\n"
             "<tr><td>Local IP</td><td><a href='http://%s'>%s</a></td></tr>\n"
+            "<tr><td>MAC</td><td>%s</td></tr>\n"
             "<tr><td>Free heap space</td><td>%6d bytes</td></tr>\n"
+            "<tr><td>Largest heap block</td><td>%6d bytes</td></tr>\n"
             "<tr><td>Max loop duration</td><td>%5d ms</td></tr>\n"
             "<tr><td>Board</td><td>%s</td></tr>\n"
+            "<tr><td>Ampel firmware</td><td>%s</td></tr>\n"
             "<tr><td>Uptime</td><td>%2d d %4d h %02d min %02d s</td></tr>\n"
             "</table>\n"
             "<div id='log' class='pure-u-1 pure-u-md-1-2'></div>\n"
+            "<form action='/command'><input type='text' id='send' name='send'><input type='submit' value='Send'></form>\n"
 #ifdef AMPEL_CSV
             "<form action='/delete_csv' method='POST' onsubmit=\"return confirm('Are you really sure you want to delete all data?') && (document.body.style.cursor = 'wait');\">"
             "<input type='submit' value='Delete CSV'/>"
@@ -130,7 +135,7 @@ namespace web_server {
 #ifdef AMPEL_CSV
             "<script>\n"
             "document.body.style.cursor = 'default';\n"
-            "fetch('./%s',{credentials:'include'})\n"
+            "fetch('%s',{credentials:'include'})\n"
             ".then(response=>response.text())\n"
             ".then(csvText=>csvToTable(csvText))\n"
             ".then(htmlTable=>addLogTableToPage(htmlTable))\n"
@@ -173,15 +178,16 @@ namespace web_server {
 
     // Web-server
     http.on("/", handleWebServerRoot);
+    http.on("/command", handleWebServerCommand);
 #ifdef AMPEL_CSV
-    http.on("/" + csv_writer::filename, handleWebServerCSV);
+    http.on(csv_writer::filename, handleWebServerCSV); //NOTE: csv_writer should have been initialized first.
     http.on("/delete_csv", HTTP_POST, handleDeleteCSV);
 #endif
     http.onNotFound(handlePageNotFound);
     http.begin();
 
     Serial.print(F("You can access this sensor via http://"));
-    Serial.print(SENSOR_ID);
+    Serial.print(ampel.sensorId);
     Serial.print(F(".local (might be unstable) or http://"));
     Serial.println(WiFi.localIP());
   }
@@ -207,44 +213,49 @@ namespace web_server {
 
     //NOTE: Splitting in multiple parts in order to use less RAM
     char content[2000]; // Update if needed
-    // Header size : 1611 - Body size : 1800 - Script size : 1920
+    // INFO - Header size : 1767 - Body size : 1991 - Script size : 1909
 
-    // Header
+    snprintf_P(content, sizeof(content), header_template, sensor::co2, ampel.sensorId, wifi::local_ip
-    snprintf_P(content, sizeof(content), header_template, sensor::co2, SENSOR_ID.c_str(),
-        WiFi.localIP().toString().c_str()
 #ifdef AMPEL_CSV
-        , csv_writer::filename.c_str()
+        , csv_writer::filename
 #endif
         );
 
+    //    Serial.print(F("INFO - Header size : "));
+    //    Serial.print(strlen(content));
     http.setContentLength(CONTENT_LENGTH_UNKNOWN);
     http.send_P(200, PSTR("text/html"), content);
 
     // Body
-    snprintf_P(content, sizeof(content), body_template, SENSOR_ID.c_str(), sensor::co2, sensor::temperature,
+    snprintf_P(content, sizeof(content), body_template, ampel.sensorId, sensor::co2, sensor::temperature,
-        sensor::humidity, sensor::timestamp.c_str(), config::measurement_timestep,
+        sensor::humidity, sensor::timestamp, config::measurement_timestep,
 #ifdef AMPEL_CSV
-        csv_writer::last_successful_write.c_str(), config::csv_interval, csv_writer::getAvailableSpace() / 1024,
+        csv_writer::last_successful_write, config::csv_interval, csv_writer::getAvailableSpace() / 1024,
 #endif
 #ifdef AMPEL_MQTT
-        mqtt::connected ? "Yes" : "No", mqtt::last_successful_publish.c_str(), config::sending_interval,
+        mqtt::connected ? "Yes" : "No", mqtt::last_successful_publish, config::mqtt_sending_interval,
 #endif
 #if defined(AMPEL_LORAWAN) && defined(ESP32)
-        lorawan::connected ? "Yes" : "No", LMIC_FREQUENCY_PLAN, lorawan::last_transmission.c_str(),
+        lorawan::connected ? "Yes" : "No", LMIC_FREQUENCY_PLAN, lorawan::last_transmission,
         config::lorawan_sending_interval,
 #endif
-        config::temperature_offset, SENSOR_ID.c_str(), SENSOR_ID.c_str(), WiFi.localIP().toString().c_str(),
+        config::temperature_offset, config::auto_calibrate_sensor ? "Yes" : "No", ampel.sensorId, ampel.sensorId,
-        WiFi.localIP().toString().c_str(), get_free_heap_size(), max_loop_duration, BOARD, dd, hh, mm, ss);
+        wifi::local_ip, wifi::local_ip, ampel.macAddress, ESP.getFreeHeap(), esp_get_max_free_block_size(),
+        ampel.max_loop_duration, ampel.board, ampel.version, dd, hh, mm, ss);
 
+    //    Serial.print(F(" - Body size : "));
+    //    Serial.print(strlen(content));
     http.sendContent(content);
 
     // Script
     snprintf_P(content, sizeof(content), script_template
 #ifdef AMPEL_CSV
-        , csv_writer::filename.c_str(), SENSOR_ID.c_str()
+        , csv_writer::filename, ampel.sensorId
 #endif
         );
 
+    //    Serial.print(F(" - Script size : "));
+    //    Serial.println(strlen(content));
     http.sendContent(content);
   }
 
@@ -255,7 +266,9 @@ namespace web_server {
     }
     if (FS_LIB.exists(csv_writer::filename)) {
       fs::File csv_file = FS_LIB.open(csv_writer::filename, "r");
-      http.sendHeader("Content-Length", String(csv_file.size()));
+      char csv_size[10];
+      snprintf(csv_size, sizeof(csv_size), "%d", csv_file.size());
+      http.sendHeader("Content-Length", csv_size);
       http.streamFile(csv_file, F("text/csv"));
       csv_file.close();
     } else {
@@ -267,14 +280,23 @@ namespace web_server {
     if (!shouldBeAllowed()) {
       return http.requestAuthentication(DIGEST_AUTH);
     }
-    Serial.print("Removing CSV file...");
+    Serial.print(F("Removing CSV file..."));
     FS_LIB.remove(csv_writer::filename);
-    Serial.println(" Done!");
+    Serial.println(F(" Done!"));
     http.sendHeader("Location", "/");
     http.send(303);
   }
 #endif
 
+  void handleWebServerCommand() {
+    if (!shouldBeAllowed()) {
+      return http.requestAuthentication(DIGEST_AUTH);
+    }
+    http.sendHeader("Location", "/");
+    http.send(303);
+    sensor_console::execute(http.arg("send").c_str());
+  }
+
   void handlePageNotFound() {
     http.send(404, F("text/plain"), F("404: Not found"));
   }

ampel-firmware/web_server.h

@@ -1,5 +1,6 @@
 #ifndef WEB_SERVER_H_
 #define WEB_SERVER_H_
+
 #if defined(ESP8266)
 #  include <ESP8266WebServer.h>
 #elif defined(ESP32)
@@ -8,7 +9,9 @@
 
 #include "config.h"
 #include "util.h"
+#include "wifi_util.h"
 #include "co2_sensor.h"
+#include "sensor_console.h"
 #ifdef AMPEL_CSV
 #  include "csv_writer.h"
 #endif

ampel-firmware/wifi_util.cpp

@@ -12,15 +12,47 @@ namespace config {
 #endif
 }
 
+namespace wifi {
+  char local_ip[16]; // "255.255.255.255\0"
+
+  void scanNetworks() {
+    Serial.println();
+    Serial.println(F("WiFi - Scanning..."));
+    bool async = false;
+    bool showHidden = true;
+    int n = WiFi.scanNetworks(async, showHidden);
+    for (int i = 0; i < n; ++i) {
+      Serial.print(F("  * '"));
+      Serial.print(WiFi.SSID(i));
+      Serial.print(F("' ("));
+      int16_t quality = 2 * (100 + WiFi.RSSI(i));
+      Serial.print(util::min(util::max(quality, 0), 100));
+      Serial.println(F(" %)"));
+    }
+    Serial.println(F("Done!"));
+    Serial.println();
+  }
+
+  void showLocalIp() {
+    Serial.print(F("WiFi - Local IP : "));
+    Serial.println(wifi::local_ip);
+    Serial.print(F("WiFi - SSID : "));
+    Serial.println(WIFI_SSID);
+  }
+
   // Initialize Wi-Fi
-void WiFiConnect(const String &hostname) {
+  void connect(const char *hostname) {
+
+    sensor_console::defineCommand("wifi_scan", scanNetworks, F("(Scans available WiFi networks)"));
+    sensor_console::defineCommand("local_ip", showLocalIp, F("(Displays local IP and current SSID)"));
+
     //NOTE: WiFi Multi could allow multiple SSID and passwords.
     WiFi.persistent(false); // Don't write user & password to Flash.
     WiFi.mode(WIFI_STA); // Set ESP to be a WiFi-client only
 #if defined(ESP8266)
     WiFi.hostname(hostname);
 #elif defined(ESP32)
-  WiFi.setHostname(hostname.c_str());
+    WiFi.setHostname(hostname);
 #endif
 
     Serial.print(F("WiFi - Connecting to "));
@@ -36,10 +68,13 @@ void WiFiConnect(const String &hostname) {
       led_effects::showKITTWheel(color::green);
       Serial.println();
       Serial.print(F("WiFi - Connected! IP address: "));
-    Serial.println(WiFi.localIP());
+      IPAddress address = WiFi.localIP();
+      snprintf(local_ip, sizeof(local_ip), "%d.%d.%d.%d", address[0], address[1], address[2], address[3]);
+      Serial.println(local_ip);
     } else {
       //TODO: Allow sensor to work as an Access Point, in order to define SSID & password?
       led_effects::showKITTWheel(color::red);
       Serial.println(F("Connection to WiFi failed"));
     }
   }
+}

ampel-firmware/wifi_util.h

@@ -5,6 +5,9 @@
 #include "util.h"
 #include "led_effects.h"
 
-void WiFiConnect(const String &hostname);
+namespace wifi {
+  extern char local_ip[];
+  void connect(const char *hostname);
+}
 
 #endif