Measure air quality and represent it with Traffic Light LEDs
- MH-Z19C Infrared CO₂ Sensor: https://www.berrybase.de/mh-z19c-infrarot-co2-sensor-stecker-kabel
- LED Traffic lights, like https://www.berrybase.de/led-ampel-modul-mit-3x-8mm-led-rot-gelb-gruen-5v
- Raspberry Pi 4
- Female-Female Jumper Wires
See Raspberry Pi GPIO Pin Layout: https://pinout.xyz/
| MH-Z19C (CO₂ Sensor) | Raspberry Pi Pins |
|---|---|
| GND (Ground) | 6 (Ground) |
| Vin | 4 (5v Power) |
| RX | 8 (GPIO 14/UART TX) |
| TX | 10 (GPIO 15/UART RX) |
Check CO₂ sensor device is registered as serial terminal: $ ls /dev/serial0
| Traffic Lights (LED Output) | Raspberry Pi Pins |
|---|---|
| GND (Ground) | 14 (Ground) |
| Red | 15 (GPIO 22) |
| Yellow | 13 (GPIO 27) |
| Green | 16 (GPIO 23) |
The software can:
- set Traffic Light LEDs
- serve measurements via webserver
Download binary from releases section
./co2indicator --server :8080 --led-pin.green=23 --led-pin.yellow=27 --led-pin.red=22 --device /dev/serial0Check measurements: curl localhost:8080
docker run -it --rm --restart=unless-stopped \
--device /dev/serial0 \
--volume /sys/class/gpio:/sys/class/gpio \
--volume /sys/devices/platform/soc/3f200000.gpio:/sys/devices/platform/soc/3f200000.gpio \
ghcr.io/knrdl/co2indicator:edge \
--led-pin.green=23 --led-pin.yellow=27 --led-pin.red=22cd src
GOOS=linux GOARCH=arm GOARM=7 go build
scp app pi@raspberrypi:/home/pi
ssh pi@raspberrypi '/home/pi/app --server :8080 --led-pin.green=23 --led-pin.yellow=27 --led-pin.red=22'