Automatic control of ventilation fans based on temperature and/or humidity
Uses a tweaked version of AHT20 for Pico so that I can have two AHT20 devices, one for inside and one for outside. The AHT20 unfortunately has a fixed I2C address so I needed to use both I2C buses.
The basic plan is "Don't make things worse", so e.g. if outside humidity is higher than inside, it won't start the fans, but there is also a provision for Summer cooling (untested till Summer arrives).
| Pico Pins | Device |
|---|---|
| gpio16 | SDA - AHT20 inside |
| gpio17 | SCL - AHT20 inside |
| gpio26 | SDA - AHT20 outside |
| gpio27 | SCL - AHT20 outside |
| gpio21 | SDA - Relay input |