A RaspberryPi based thermostat project
The 1wire DS18B20's are connected to GPIO4 pin
This program is currently live on a single stage HEAT only application. A planned H3/C2 implementation that will control my GeoThermal is in the works.
Geo Notes: DX18x20 Inputs - Indoor Temp Plenum Temp Intake Temp Outdoor Temp
Relay Outputs - G - Fan Control Y1 - Stage 1 Y2 - Stage 2 W - Aux Heat O - Reversing valve.
Signal Table - G = Fan Only G + Y1 = Stage 1 Heat G + Y1 + Y2 = Stage 2 Heat G + Y1 + Y2 + W = Stage 3 Heat G + W = Emergency Heat G + Y1 + O = Stage 1 Cool G + Y1 + Y2 + O = Stage 2 Cool
User Inputs: Target Temperature
Programmatic Inputs: Time in current state Temperature rise / fall % of target while in current state Efficiency as defined by difference in return and plenum