Supports triggering General Purpose Input Output (GPIO) pins on platforms supporting the onoff package. It is based on homebridge-gpio, but using the onoff package instead of pi-gpio to be able to listen for changes in pin values.

• Homebridge - HomeKit support for the impatient
• onoff - Reading and writing GPIO pins and listening for changes

1. Install Homebridge using npm install -g homebridge
2. Install this plugin npm install -g homebridge-gpio-onoff
3. Update your configuration file

Example config.json, creating a switch accessory that the user can switch on and off, setting the GPIO pin value to '1' or '0', respectively:

{
  "accessories": [
    {
      "accessory": "GPIO-OnOff",
      "name": "GPIO-7",
      "pin": 7,
      "direction": "out"
    }
  ]
}

accessory should be set to GPIO-OnOff for this plugin. name is the accessory's name, which is shown in HomeKit. pin is the physical GPIO pin number. direction can be set to either in to read from the GPIO pin or out to write to the pin. If set to in, the edge property can be set to rising, falling or both to have a changing GPIO pin value trigger an accessory value change (it is set to none by default).

By default, a simple 'Switch' accessory is created, which will be set to 'On' or 'Off' by a change in the input value. It is possible to change the service type and even the true and false values. For example, to have it act like a light sensor, you can specify:

{
  "accessories": [
    {
      "accessory": "GPIO-OnOff",
      "name": "GPIO-7",
      "pin": 7,
      "direction": "in",
      "edge": "both",
      "activeLow": true,
      "hapService": "LightSensor",
      "hapCharacteristic": "CurrentAmbientLightLevel",
      "trueValue": 100000,
      "falseValue": 0.0001
    }
  ]
}

activeLow will treat '0' as the true value and '1' as the false value. hapService can be set to one of the defined services in HomeKitTypes.js and hapCharacteristic to one of the characteristics defined for the service. If the characteristic values are not boolean, you can specify the values for true and false by setting trueValue and falseValue, respectively.