Raspberry Pi Thermostat Instructions

Here are some details on how I put together my Raspberry Pi thermostat.



My apartment's thermostat uses a very simple mechanism to control the heater:



Connecting the red wire to the white wire turns on the heater. Near the center of the thermostat is a glass vial containing some mercury. If the vial tilts to the right the mercury creates a connection between the wires. I attached the two black wires on the bottom and use the Raspberry Pi to control the connection between the wires. The original thermostat remains fully functional: the heater will turn on if either the Raspberry Pi or the original thermostat signal it to turn on.



Materials used:

• Raspberry Pi 2 Model B
• USB Wifi
• Pi Cobbler Plus
• Power supply
• SD card
• Songle SRD-05VDC-SL-C Relay
• Breadboard
• Wires

The relay module controls the connection between the two heater wires. GPIO output from the Raspberry Pi can turn the connection on/off. The connection is off by default - even when the Raspberry Pi is powered off. I SSH into the Raspberry Pi to control the GPIO pin over the Internet.