Homebridge Pi Thermostat Plugin for DS18B20 1-Wire Sensor

This is a homebridge plugin to make a Raspberry Pi connected with a Relay Board and DS12B20 Temperature Sensor into a smart thermostat that can be controlled via the Home app on iOS using Homekit.

Guide

For those who want to create their own thermostat using Raspberry Pi, here is a blog post that goes through the details of where to buy the parts, how to assemble it and what software to install to get this to work.

Installation

• Install nodejs and other dependencies for homebridge to work

curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
sudo apt-get install -y nodejs libavahi-compat-libdnssd-dev

• Install homebridge and this plugin

sudo npm install -g --unsafe-perm homebridge homebridge-pi-thermostat

• Add the accessory config to your homebridge config file located at this path ~/.homebridge/config.json.

{
  "bridge": {
    "name": "Homebridge",
    "username": "CC:22:3D:E3:CE:30",
    "port": 51826,
    "pin": "031-45-154"
  },
  "description": "",
  "accessories": [
    {
      "accessory": "Thermostat",
      "name": "Pi Thermostat",
      "fanRelayPin": 26,
      "heatRelayPin": 21,
      "coolRelayPin": 20,
      "temperatureSensorPin": 4,
      "minimumOnOffTime": 120000,
      "blowerTurnOffTime": 80000,
      "startDelay": 10000,
      "temperatureCheckInterval": 10000
    }
  ],
  "platforms": []
}

• Start it up by running homebridge command.

Configuration

Relay Pins

You can change the pin to turn on and off the relay switch for the Fan, Heat and Cool setting.

"fanRelayPin": 26,
"heatRelayPin": 21,
"coolRelayPin": 20,

Timing

The system has a minimum on off time which is in miliseconds and is the minimum time it keeps the Heat or Cool turned on and off so that it does not damage the heating or cooling system by turning on and off very quickly.

"minimumOnOffTime": 120000,

The system also has a blowerTurnOffTime which is the time it takes to turn off the blower after Heat or Cool is turned off.

"blowerTurnOffTime": 80000,

The interval for checking the temperature of the room can also be set and defaults to 10 seconds.

"temperatureCheckInterval": 10000

Screenshots