A Raspberry Pi environmental monitoring station that has been running continuously since 2022. It measures CO₂, temperature, humidity, air pressure, light level and particulate matter, writes everything to a local InfluxDB, and shows it on a Grafana dashboard on its own touch display.
Custom PCB, 3D-printed housing, and a row of DIP switches on the side so it can be handled without a keyboard.
The finished station on the shelf, showing the last few hours of temperature, humidity and CO₂.
| Sensor | Bus | Measures |
|---|---|---|
| SCD30 | I²C | CO₂, temperature, humidity |
| BME280 | I²C | Temperature, humidity, air pressure |
| TSL2591 | I²C | Light level (lux) |
| SDS011 | USB serial | Particulate matter, PM2.5 and PM10 |
| DS3231 | I²C | Real-time clock, so the station keeps time without WiFi |
Readings go into InfluxDB on the Pi itself and are drawn in Grafana. Nothing leaves the flat.
Once a minute, via cron: SCD30.py, BME280.py, TSL2591.py
Each reads its sensor, writes one point to InfluxDB, and exits. The crontab is in crontab.txt.
Daemons started at boot:
SDS011.py— reads the particulate sensor continuously over/dev/ttyUSB0DipSwitch.py— polls the four DIP switchesScreenControl.py— display backlight
Daily: timesync.sh brings WiFi up, syncs NTP, writes the time to the RTC, then puts WiFi back the way it found it.
Four switches on the side of the case, because reaching for SSH to turn off a dust sensor is silly:
| Switch | GPIO | Function |
|---|---|---|
| 1 | 27 | SDS011 particle sensor on/off |
| 2 | 17 | Unassigned |
| 3 | 4 | WiFi on/off |
| 4 | 24 | System shutdown |
A PIR sensor (GPIO 22) plus the TSL2591 light reading decide when the DSI display wakes up. Walk past in a lit room and it comes on for 60 seconds, then goes dark again. In the dark (lux < 5) it stays off, so it doesn't light up the room at night.
Full pin assignment is in GPIO_PINOUT.md.
Left: the printed housing, PIR dome and CO₂ sensor on the side panel. Right: the original Fusion 360 exploded view — the Nova PM (SDS011) sensor sits in the base, the Pi and the custom HAT above it.
hardware/
├── enclosure/ 4 printable STLs: main body, side housing, side wall, stand
└── pcb/ EAGLE schematic + Gerbers (v12, April 2022)
The enclosure prints in four parts. The hex-pattern vents let air reach the sensors without letting the light sensor see straight out.
Not included here: the Sensirion SCD30 driver, vendor datasheets, and third-party CAD models for the Pi display and connectors — get those from the manufacturers.
influxdb
adafruit-circuitpython-bme280
adafruit-circuitpython-tsl2591
adafruit-circuitpython-ds3231
scd30_i2c
gpiozero
rpi_backlight
pyserial
No build step, no virtualenv — the scripts run directly on the Pi.
- All I²C sensors share GPIO 2 (SDA) and GPIO 3 (SCL).
- The DS3231 is claimed by the kernel at
0x68and reached throughhwclock, not Python. - Station altitude is hardcoded to 435 m in
BME280.pyfor the sea-level pressure conversion — change that if you build one somewhere else.
Built for my own flat, and still running. Happy to answer questions if you're building something similar.