CO₂ Ampel

CO₂ Ampel is an open-source project, written in C++ for ESP8266 or ESP32.

It measures the current CO₂ concentration (in ppm), and displays it on an LED ring.

The room should be ventilated as soon as one LED turns red.

Features

The CO₂ Ampel can:

• Display CO2 concentration on LED ring.
• Allow calibration.
• Get current time over NTP
• Send data over MQTT.
• Send data over LoRaWAN.
• Display measurements and configuration on a small website.
• Log data to a CSV file, directly on the ESP flash memory.
• Accept many interactive commands.

Hardware Requirements

• ESP8266 or ESP32 microcontroller (this project has been tested with ESP8266 ESP-12 WIFI and TTGO ESP32 SX1276 LoRa)
• Sensirion SCD30 "Sensor Module for HVAC and Indoor Air Quality Applications"
• NeoPixel Ring - 12, or NeoPixel Ring - 16 (experimental)

See the documentation for more info.

Software Requirements

• PlatformIO or
• Arduino IDE

Installation

• If config.h does not exist, copy it from config.public.h
• Modify config.h, e.g. for measurement time-steps, WiFi access, MQTT, NTP and web-server.

PlatformIO

PlatformIO can be run from VSCODE, Eclipse CDT or console:

make upload board=esp8266 && make monitor # For ESP8266

make upload board=esp32 && make monitor # For ESP32

Arduino IDE

• All the libraries are included in this repository. No need to install anything via Library Manager.

• Add your board to the board manager. Either ESP8266:

    http://arduino.esp8266.com/stable/package_esp8266com_index.json
  

  or ESP32:

    https://dl.espressif.com/dl/package_esp32_index.json
  

• Choose the correct board in Tools > Board > ...

• Choose the correct Flash size (e.g. "Flash Size : 4MB (1MB FS, OTA:~1019kB)" for ESP8266 ESP-12 WIFI)

• Verify

• Upload

• Tools > Serial Monitor

Available commands

In Arduino IDE Serial Monitor or PlatformIO Monitor, type help + Enter 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 (HfT Stuttgart)
• Robert Otto (HfT Stuttgart)
• Myriam Guedey (HfT Stuttgart)
• Tobias Gabriel Erhart (HfT Stuttgart)
• Jonas Stave (HfT Stuttgart)
• Michael Käppler

Contributing

• 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 © 2021, HfT Stuttgart GPLv3