PI MQTT GPIO

Expose the Raspberry Pi GPIO pins (and/or external IO modules such as the PCF8574) to an MQTT server. This allows pins to be read and switched by reading or writing messages to MQTT topics.

Installation

pip install pi-mqtt-gpio

Execution

python -m pi_mqtt_gpio.server config.yml

Configuration

Configuration is handled by a YAML file which is passed as an argument to the server on startup.

Pins

With the following example config, switch pin 21 on by publishing to the home/kitchen/output/lights/set topic with a payload of ON, and pin 22 by publishing to home/kitchen/output/fan/set.

mqtt:
  host: test.mosquitto.org
  port: 1883
  user: ""
  password: ""
  topic_prefix: home/kitchen

gpio_modules:
  - name: raspberrypi
    module: raspberrypi

digital_outputs:
  - name: lights
    module: raspberrypi
    pin: 21
    on_payload: "ON"
    off_payload: "OFF"
  
  - name: fan
    module: raspberrypi
    pin: 22
    on_payload: "ON"
    off_payload: "OFF"

Or to receive updates on the status of an input pin, subscribe to the home/input/doorbell topic:

mqtt:
  host: test.mosquitto.org
  port: 1883
  user: ""
  password: ""
  topic_prefix: home

gpio_modules:
  - name: raspberrypi
    module: raspberrypi

digital_inputs:
  - name: doorbell
    module: raspberrypi
    pin: 22
    on_payload: "ON"
    off_payload: "OFF"
    pullup: yes
    pulldown: no

Modules

The IO modules are pluggable and multiple may be used at once. For example, if you have a Raspberry PI with some GPIO pins in use and also a PCF8574 IO expander on the I2C bus, you'd list two modules in the gpio_modules section and set up the inputs and outputs accordingly:

mqtt:
  host: test.mosquitto.org
  port: 1883
  user: ""
  password: ""
  topic_prefix: pimqttgpio/mydevice

gpio_modules:
  - name: raspberrypi
    module: raspberrypi

  - name: pcf8574
    module: pcf8574
    i2c_bus_num: 1
    chip_addr: 0x20

digital_inputs:
  - name: button
    module: raspberrypi
    pin: 21  # This device is connected to pin 21 of the Raspberry PI GPIO
    on_payload: "ON"
    off_payload: "OFF"
    pullup: no
    pulldown: yes

digital_outputs:
  - name: bell
    module: pcf8574
    pin: 2  # This device is connected to pin 2 of the PCF8574 IO expander
    on_payload: "ON"
    off_payload: "OFF"