My parents growing their own organic food and they asked me to deal with winter temperatures problem in the storage room. It gets really cold here, in Ukraine. Some winters have even lower temperatures than -30°C (-22°F). So right now I designing a simple thermostat for keeping temperature at about 5-7 degrees C above zero. Plus right now I started to use my garage as a gym, so this thermostat would be handy there too.
- ATMEL AVR ATtiny2313
- BS-901AS Relay
- DB107 Bridge rectifier
- DS18B20 Temperature sensor
- E30361-L-0-8-W 7-Segments LED display
- L78xx series linear voltage regulators
Some of the parts for this project.
And how they would fit in the box.
12V 3VA Transformer.
Just a small heads up about low-power transformers like this one: without load they will give you much higher voltage, than rated.
For example this transformer gives me about 24V with no load at all, and about 15V with 160mA load! So when picking a smoothing capacitor you need to take that into account. In this case capacitor voltage should be at least 35V (50V is better)!