Thermostat using a Raspberry Pi Pico
This circuit uses a 2222 npn transistor, Raspberry Pi Pico, and dht20 to control a 12V DC fan.
You define a temperature threshold to turn the fan on or off.
An OLED screen is also setup to view the temperature and output.
Basic premise schmatic
Fritzing Schematic
Pico Pi Pin Setup to Transistor/Circuit
| Pin | Component |
|---|---|
| Collector | DC fan Black wire |
| Base | 470 Ohm resistor |
| 470 Ohm resistor | power/+ on breadboard rail |
| Emitter | Black wire of the 12 V power |
| Emitter | ground/- on the breadboard rail (shared) |
| GPIO 15/ANY | power/+ on breadboard rail |
| ANY GND/Pin38 | power/- on breadboard rail (shared) |
| Red wire of the 12 V power supply | red wire of the DC Fan |
NOTE: I use GPIO 15 in the code, but show GPIO 9 in the Fritzing to lessen clutter
dht20 Connections
| GPIO Pin | Connection |
|---|---|
| GPIO 12 | SDA |
| GPIO 13 | SCL |
| GND | GND |
| 5V/PIN40 | VCC |
OLED Connections
| GPIO Pin | Connection |
|---|---|
| GPIO 18 | SDA |
| GPIO 19 | SCL |
| GND | GND |
| 5V/PIN40 | VCC |
Pics
Install:
- Upload this whole repo into / on the pico using a recent micropython firmware
- Edit TRIGGER_TEMP to your desired temperate trigger in basic_temp.py
- Power on the Pico with USB and turn on the 12V power supply - start at 5V and turn up to 12V as you like.
Credits |dht20 driver|ssd1306 driver|Schematic Image|
License MIT