A small box which will display the Air Quality Index based on the US EPA formula, using a $15 sensor and $10 microcontroller and display. As the AQI climbs, the background color changes, matching the colors used on PurpleAir. The display is a 1.1" TFT, bright enough to be seen in daylight from across a large room.
- 30 seconds of data gathering and averaging of particle count to calculate AQI
- Color changing background based on AQI value
- Displays latest calculated value every 1 minute for the first 30 minutes. Then goes into a Sleep Mode to preserve the sensors fan, calculating a new AQI value every 30 minutes.
- Written in micropython, everything is easily configurable.
- Front button to begin gathering on demand
- Can be made portable with the use of a USB Power Bank
- LILYGO® TTGO T-Display ESP32 aliexpress
- Plantower PMS7003 Air Quality Sensor + G7 Adapter aliexpress
Easiest way to setup the software is to hook up the T-Display to a computer running Thonny and follow these instructions to flash this custom firmware, which includes drivers for writing to the display included with the T-Display device.
Then you can copy to the device all the *.py files from this repository and customize them if required.
Attach the G7 Adapter to the PMS7003 sensor, it will only fit one way. Connect the included cable to the adapter and cut off the other end to expose the wires. Strip, connect and solder the following connections:
| PMS7003 | T-Display |
|---|---|
| VCC | 5V |
| GND | G |
| RX | 26 |
| TX | 25 |
The T-Display schematic can be found here.
The two components can be taped together quite easily. But if you have access to a 3d printer you can use the included STL files (in the case/ directory) to print a case and fit the components inside. It uses a sliding dovetail top which can be printed separately.
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