Documentation

GPIO Extension

The GPIO extension controls and monitors GPIO pins on Linux SBC boards such as a Raspberry Pi using adafruit-blinka.

Overview

The gpio extension controls and monitors GPIO pins connected to a Linux SBC board such as a Raspberry Pi. Provided are a set of interfaces through the support of adafruit-blinka. There are a large variety of supported Linux boards that you can use.

This extension does not take an extension-level config and is focused on interfaces.

Sensor Interface

Provides a sensor that returns a GPIO pin reading.

Option	Type	Required	Description
`key`	String	Yes	Unique slug id for the component
`pin`	String	Yes	GPIO pin to use on board, e.g. `D12` or `A1`
`name`	String	No	Friendly display name of component. Useful for UI.
`classifier`	String	No	Choose a specific sensor classifier to change formatting on frontend. Default: `general`

Config Example

mudpi.config.json

{
  "sensor": [
    {
      "key": "gpio_sensor_D12",
      "interface": "gpio",
      "pin": "D12",
      "classifier": "general"
    }
  ]
}

Control Interface

Attach a control to a Linux board GPIO such as a button, switch, or potentiometer.

Option	Type	Required	Description
`key`	String	Yes	Unique slug id for the component
`pin`	String	Yes	GPIO pin to use on board, e.g. `D12` or `A1`
`name`	String	No	Friendly display name of component. Useful for UI.
`type`	String	No	Type of control behavior. Options: `button`, `control`, or `potentiometer`. Default: `button`
`resistor`	String	No	Set internal resistor to pull `up` or pull `down`. Default: `None`
`edge_detection`	String	No	Set edge detection on GPIO for more responsive feedback. Options: `rose`, `fell`, or `both`
`debounce`	Float	No	Time in seconds to wait for GPIO to settle before firing. Prevents multiple fires from one press. Default: `0`. A good starting value is `0.05`.

Config Example

mudpi.config.json

{
  "control": [
    {
      "key": "gpio_button_D12",
      "interface": "gpio",
      "name": "Button Pin D12",
      "type": "button",
      "resistor": "down",
      "edge_detection": "both",
      "debounce": 0.05
    }
  ]
}

Note

Be mindful of how edge_detection works. It is suggested to use the both option. MudPi still checks for the actual pin state and uses this for what is stored. Additional events ControlPressed and ControlReleased are emitted for edge detection changes. These events are reversed if invert_state is true.

Toggle Interface

Provides a toggle that can turn a GPIO pin on or off.

Option	Type	Required	Description
`key`	String	Yes	Unique slug id for the component
`pin`	String	Yes	GPIO pin to use on board, e.g. `D12` or `A1`
`name`	String	No	Friendly display name of component. Useful for UI.
`max_duration`	Integer	No	Failsafe duration (in seconds) to turn off toggle after. 0 means off. Default: `0`
`invert_state`	Boolean	No	Set to `true` if toggle is off when pin is in HIGH state. Default: `false`

Config Example

mudpi.config.json

{
  "toggle": [
    {
      "key": "gpio_toggle_D12",
      "interface": "gpio",
      "name": "Light - Pin D12",
      "pin": "D12",
      "max_duration": 360,
      "invert_state": false
    }
  ]
}

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