A home CO2 and temperature station with NODEMCU and thinger.io.
This project implements:
- A semaphore (using three colored LEDs) that will signal the current level of CO2 in the room in which it is installed
- All measurements are regularly updated in thinger.io, where you can use it to build your own dashboards
- High CO2 levels detection calls an endpoint in thinger.io, which you can use to trigger further actions
Overall cost of the required components is around 20€.
- NODEMCU development board
- MH-Z19 CO2 sensor
- BME280 temperature, humidity and pressure sensor
- Red. yellow and green LEDs
- 1kohm resistance (or similar order of magnitude)
All elements need to be connected to the NODEMCU board as follows:
| Element | Element Pin | NODEMCU Pin |
|---|---|---|
| BME280 | Vin | 3v3 |
| BME280 | GND | GND |
| BME280 | SCL | D5 |
| BME280 | SDA | D6 |
| MH-Z19 | Vin | Vin |
| MH-Z19 | GND | GND |
| MH-Z19 | TX | D7 |
| MH-Z19 | RX | D4 |
| Red LED | Anode | D3 |
| Red LED | Cathode | Resistance (side A) |
| Yellow LED | Anode | D2 |
| Yellow LED | Cathode | Resistance (side A) |
| Green LED | Anode | D1 |
| Green LED | Cathode | Resistance (side A) |
| Resistance | Side A | All three LED cathodes |
| Resistance | Side B | GND |
This sketch can be deployed in the NODEMCU development board using Arduino IDE Some extra libraries will be needed (downloaded directly from the Arduino IDE):
This sketch uploads measurements to the thinger.io platform as a device element. In order to get ready, you will need to:
- Create an account (from which you will get an username)
- Create a new device in your account (from which you will get a device_id and device_credential)
- Create an endpoint in your account, which will get fired whenever measured CO2 levels go too high (it can be used to trigger further actions, such as sending an alert to a chat in Telegram)
Once up and running, the created device will be populated with the following measurements:
- temperature: temperature (ºC) measurements from BME280 sensor
- pressure: pressure (mbar) measurements from BME280 sensor
- humidity: humidity (%) measurements from BME280 sensor
- co2: co2 (ppm) measurements from MH-Z19 sensor
- temperature2: temperature (ºC) measurements from MH-Z19 sensor (even though those are not accurate)
Prior to deploying this sketch, you will need to complete the following sections:
- WiFi: fill WLAN_SSID and WLAN_PASS with the SSID and password of your own WiFi connection
- Thinger.io: fill THINGERIO_USERNAME, THINGERIO_DEVICE_ID, THINGERIO_DEVICE_CREDENTIAL and THINGERIO_ENDPOINT with the corresponding information of your thinger.io account