An easy to build CO2 Monitor/Meter with cell phone App for real time visualization and charting of air data, datalogger, a variety of communication options (BLE, WIFI, MQTT, ESP-Now) and many supported sensors.
This repository is mainly addressed at developers. If you are an end user willing to build the CO2 Gadget you will find complete instructions at my blog including instructions in how to build the hardware and to load the firmware very easily, with one click in your browser (without having edit files, compile or install anything on your computer).
- Many popular CO2 sensors supported: Sensirion SCD30, Sensirion SCD40, Sensirion SCD41, Senseair S8 LP, MH-Z19, Cubic CM1106
- Supports the Air Quality App Sensirion MyAmbiance for iOS and Android with real time visualization, charting and access to historycal data
- Real time visualization on display, serial port and web page
- Management and configuration via on screen menu, serial port and web page
- Local data logger with upload to phone by BLE
- WIFI connection
- Sending of data via MQTT
- Receiving remote commands via MQTT
- Over the air updates OTA
Supported hardware and build
This project support a large selection of boards, displays and sensors.
As an example you can find a very detailed tutorial with step-by-step video on how to build a very compact CO2 Gadget with a TTGO T-Display board and a high quality Sensirion SCD30 dual channel NDIR CO2 sensor and support for battery here.
Supporting any other ESP32 board is very easy. Also, the are a large number of displays already supported.
This project uses the CanAirIO sensorlib library to support as many sensors as possible out of the box. Thanks to @hpsaturn and CanAirIO team.
CanAirIO sensorlib right now supports:
|Sensor model||UART||I2C||Detection mode||Status|
|Sensirion SPS30||Yes||Yes||Select / Auto||STABLE|
NOTE: Panasonic via UART in ESP8266 maybe needs select in detection
|Sensor model||UART||i2c||Detection mode||Status|
|Sensor model||Protocol||Detection mode||Status|
NOTE: DHT22 is supported but is not recommended
Full details on CanAirIO sensorlib here
Building from repository
First you should edit some files with your own data and preferences.
Edit the credentials.h file substituting "MyWiFiSSID" with your own WiFi SSID and "some_secret_password" with your own WiFi password in:
#define WIFI_SSID_CREDENTIALS "MyWiFiSSID" #define WIFI_PW_CREDENTIALS "some_secret_password"
If you prefer not to keep sensitive data in a file, you can define this data in environment variables so you don't need a credentials.h file with your secrets. See platformio.ini file for instructions.
If you are planning to use MQTT with authentication, substitute "MyUser" with your own MQTT user and "another_secret_password" with your own MQTT user password:
#define MQTT_USER_CREDENTIAL "MyUser" #define MQTT_PW_CREDENTIAL "another_secret_password"
You are done with credentials. Save the file credentials.h
Edit the file platformio.ini
If necessary adjust the upload and minitoring port configuration to match your situation.
upload_speed = 921600 monitor_speed = 115200 upload_port = COM13 monitor_port = COM13
If you are planning to use MQTT, edit the IP of your MQTT broker, substituting 192.168.1.145 with your broker IP address:
Save the file platformio.ini
Compiling and Installing
We recommend PlatformIO because it is more easy than Arduino IDE. For this, please install first PlatformIO and its command line tools (Windows, MacOs and Linux), pio command, then connect your compatible board to the USB and run the next command:
pio run --target upload
If using PlatformIO GUI, to compile and upload CO2-Gadget into your board, press the"Alien head" -> Project tasks -> Upload and Monitor (in the image the sanwitch version is selected).
These Arduino instructions are outdated. Sou must adapt it to your situation while I write some new instructions.
To compile this project with Arduino IDE (the integrated development enviroment), you have to install Arduino IDE, and add the libraries referenced in lib_deps in the file platformio.ini, as Arduino won't install it automatically like PlatformIO does.
To compile this project with Arduino CLI (the command line version of Arduino), you first need to install arduino-cli or the Arduino IDE with the libraries referenced in lib_deps in the file platformio.ini, because Arduino won't install it automatically like PlatformIO does.
Also, you need to add the alternative links for supporting the ESP32 boards:
For Arduino IDE: Adding the line https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json in: File > Preferences > Additional Boards Manager URLs.
For Arduino CLI: Follow the next steps:
arduino-cli config init
.arduino15/arduino-cli.yaml file add:
board_manager: additional_urls: - https://arduino.esp8266.com/stable/package_esp8266com_index.json - https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
Compiling and Installing
With Arduino IDE you just have to select Program > Upload
arduino-cli you can load CO2 Gadget in an ESP32 board following these steps:
arduino-cli core update-index arduino-cli core install esp32:esp32:esp32 arduino-cli compile --fqbn esp32:esp32:esp32 CO2_Gadget.ino arduino-cli upload --fqbn esp32:esp32:esp32:UploadSpeed=115200 -p /dev/ttyUSB0 basic
Supporting the project
If you want to contribute to the code or documentation, consider posting a bug report, feature request or a pull request.
When creating a pull request, we recommend that you do the following:
- Clone the repository
- Create a new branch for your fix or feature. For example, git checkout -b fix/my-fix or git checkout -b feat/my-feature.
- Run to any clang formatter if it is a code, for example using the
vscodeformatter. We are using Google style. More info here
- Document the PR description or code will be great
- Target your pull request to be merged with
- Test and enable WIFI feature
- Test and enable MQTT feature
- Test and enable ESP-Now feature
- Test and enable OLED Display support
- Implement full support for PM
- Enable enable and disable BLE, WiFi and MQTT without recompiling by activating/deactivating on the buit in menu
Thanks to all collaborators, contributors and eMariete community for testing and reports.
Copyright (C) 2021 CO2 Gadget Contributors Contact: https://emariete.com This file is part of the CO2 Gadget firmware. The CO2 Gadget firmware is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. The emariete.com Website and Documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the emariete.com Website and Documentation. If not, see <http://www.gnu.org/licenses/>.