/api/gpio

GPIO module provides read and write access to gpio of your Raspberry Pi. As well as pwm and tone generator (square wave) configurations.

WiringPi library is used for accessing GPIO. WiringPi pin numbers are used, check page Pins.

Read access

Shows info about configuration and values for each pin. For read access use GET methods as for any other module.

Example:

{
    "0":    {
        "mode":    "undefined",
        "pull":    "off",
        "value":    0,
        "frequency":    1000,
        "range":    100
    },
    "1":    {
        "mode":    "undefined",
        "pull":    "off",
        "value":    0,
        "frequency":    1000,
        "range":    100
    },
    ...
}

gpio/%d/mode

Specifies pin function:

• "undefined" - the pin was not initialized through REST api
• "input" - pin is input
• "output" - pin is output
• "pwm" - pin is PWM output, on pin 1 this is hardware PWM, otherwise software PWM
• "tone" - software square wave generation up to 5kHz

gpio/%d/pull

Defines pull resistor in "input" mode:

• "off" - no pull resistor (default)
• "down" - pull-down resistor
• "up" - pull-up resistor

gpio/%d/value

Value can be from 0 to range.

Meaning depends on the mode:

• "undefined", "input" - read pin value using digitalRead
• "output" - zero is low, any other value is high
• "pwm" - PWM duty cycle
• "tone" - zero disables tone, any other value is enabled

gpio/%d/frequency

Frequency in Hz for tone generation (max 5kHz) and for hardware PWM on pin 1. Default is 1kHz.

gpio/%d/range

Sets range of values for PWM. Default is 100.

Write access

REST api is the same as for read access, but for writing you have to use POST method. Put JSON with values in POST body.

Write single value

POST to gpio/%d/mode

"input"

Write more values for one pin with one request

POST to gpio/%d

{
    "mode": "input",
    "pull": "up"
}

Write more pins at the same time

POST to gpio

{
    "0": {
        "mode": "input"
    },
    "5": {
        "mode": "output",
        "value": 1
    }
}

WebSocket

For accessing GPIO WebSocket interface connect to gpio/ws with $.rpijs.websocket().

The server broadcasts information about pin value changes when the pin is in input mode. The message is in JSON object format.

You cannot send any commands to server via websocket.

Example message (pin 1 changed value to 1):

{
    "1": "1"
}