GPIO

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 i.e. `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 Examples

Here is a config of a complete gpio sensor.

"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 i.e. `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

Here is a config of a complete gpio control.

"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. If you listen to just the fell or rose events technically you would never know when the state is the opposite. To help, MudPi still checks for the actual pin state and uses this for what is stored. It is suggested to use the both option for edge_detection.

Additional events are exposed to interact with these edge detection changes. ControlPressed is emitted when a rose edge is detected and ControlReleased when a fell detected. These events are reveresed 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 i.e. `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

Here is a config of a complete gpio toggle.

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