myGPIOd Configuration

Configuration steps

• Adapt the configuration file /etc/mygpiod.conf to your needs. All options are documented in the file.

• Create GPIO configuration files in the directory /etc/mygpiod.d. There are documented example configuration files for input and output configuration. myGPIOd only accesses GPIOs configured in this files.

• GPIO configuration file names: <gpio number>.<direction>

  • <gpio number>: This is the line number of the GPIO.

  • <direction>: Configures the GPIO line direction, in for input and out for output.

Events

Events are triggered through changes of input GPIO values.

Event	Description and options
gpio_falling	State of GPIO has changed from active to inactive. action_falling: Action to execute.
gpio_rising	State of GPIO has changed from inactive to active. action_rising: Action to execute.
gpio_long_press	GPIO was pressed long. long_press_event: Event for long press falling or rising. long_press_timeout: Timeout a button is considered as long pressed. long_press_action: Action for long press. long_press_interval: Action is repeated in this interval until button is released, set to 0 to disable.
gpio_long_press_release	GPIO changing it’s state after a long press event. long_press_release_action: Action executed when button was released.
input	An input event has occurred.

GPIO events

myGPIOD can read edge events from GPIO lines and execute configured actions. Only one GPIO device can be configured.

# GPIO chip device
chip = /dev/gpiochip0

Which GPIO lines to use are configured with one file per line in the directory /etc/mygpiod.d.

Input events

myGPIOd read events from /dev/input/… devices and execute configured actions. Which input device to use and which is the correct event type, code and value can easily determined with the evtest utility.

#input_ev = device:type:code:value:action:options
input_ev = /dev/input/event0:EV_KEY:KEY_POWER:1:system:/home/juergen/projekte/myGPIOd/etc/command.sh

# Register event without action, only the state is tracked
input_ev = /dev/input/event3:EV_KEY:KEY_LEFTSHIFT:*:none

# Register a simple button press
input_ev = /dev/input/event3:EV_KEY:KEY_N:1:lua:keyPress N

• Supported event types: EV_KEY, EV_REL, EV_ABS, EV_SW

• Event code and value can be * to match all.

• Multiple actions can be defined per event.

Hint

You can use the evtest utility to determine the correct device, type, code and value.

Note

To handle key modifiers like Shift or Ctrl simply register the modifier keys without an action and use a Lua script to determine the state.

Actions

Each event can have multiple actions. Actions and its arguments are delimited by a colon, arguments are delimited by space.

action_falling = {action}:{arg1} {arg2} ...
action_rising = {action}:{arg1} {arg2} ...
long_press_action = {action}:{arg1} {arg2} ...
long_press_release_action = {action}:{arg1} {arg2} ...

Action	Arguments	Description
gpioblink	<gpio> <timeout_ms> <interval_ms>	Toggle the value of the GPIO after given timeout (initial delay) and interval. Set interval to 0 to blink only once.
gpioset	<gpio> <active|inactive>	Sets the value of a GPIO.
gpiotoggle	<gpio>	Toggles the value of a GPIO.
http	{method} {uri} [{content-type} {postdata}]	Submits a HTTP request in a new child process. If postdata starts with <</, the string after the << is interpreted as an absolute filepath from which the postdata is read. Requires libcurl. Valid HTTP methods are: DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT
lua	{lua function} [{option} …]	Calls a user defined lua function.
mpc	{mpd command} [{option} …]	Connects to MPD and issues the command with options. It uses the default connection settings from libmpdclient. A maximum of 10 options are supported. Requires libmpdclient.
mympd	{uri} {partition} {script}	Calls the myMPD api in a new child process to execute a myMPD script. Requires libcurl.
system	{command}	Executes an executable or script in a new child process. No arguments are allowed.

myGPIOd can take actions on rising, falling and long_press events. Long press is triggered by a falling or rising event and does not disable the triggering event, but the release event. To use a button for normal press and long_press request both events and use one event for long and the other for short press. The example below illustrates this.

Example actions

# GPIO actions
gpioblink:5 1000 2000
gpioset:5 active
gpiotoggle:5

# Execute HTTP actions
http:GET http://server.lan/webhook1
http:PATCH http://server.lan/webhook1 application/json '{"value": 1}'
http:POST http://server.lan/webhook2 text/plain <</tmp/postdata

# Execute a custom lua function
lua:my_lua_func arg1 arg2

# Execute mpd commands
mpc:next
mpc:volume 5

# Start a script in myMPD
mympd:http://localhost:8443 default script1

# Execute a system command
system:/bin/true

Example configuration

/etc/mygpiod.conf

# GPIO chip to use
chip = /dev/gpiochip0

# The loglevel
loglevel = info

# Log to stdout
syslog = 0

# Directory for GPIO configuration files
gpio_dir = /etc/mygpiod.d

# File with user defined lua functions
#lua_file = /etc/mygpiod.lua

GPIO configuration

• Configures GPIO 3 as input:

  • Enables the pull-up resistor on start

  • Sets GPIO 6 to active on falling event

  • Calls /usr/local/bin/reboot.sh after a button press (falling) of 2 seconds length

  • Toggles the value of GPIO 6 on release event of the long press event

  • Calls /usr/local/bin/poweroff.sh on a short press (rising)

  /etc/mygpiod.d/3.in

  # Configuration file for GPIO 3 as input
  # Request falling and rising events
  event_request = both
  
  # Active is high
  active_low = false
  
  # Enable the internal pull-up resistor
  bias = pull-up
  
  # Short press does a poweroff
  # The rising event is not triggered if GPIO 3 is pressed longer than 2000 ms.
  action_rising = system:/usr/local/bin/poweroff.sh
  
  # Reboot on long press and activate a LED for maximal 2s while GPIO 3 is pressed.
  
  # Set GPIO 6 active on falling
  action_falling = gpioset:6 active
  
  # Enable long press for falling.
  long_press_event = falling
  
  # Set the long press timeout to 2000 ms.
  long_press_timeout = 2000
  
  # Disable the long press interval.
  long_press_interval = 0
  
  # Action for long press is to run a script.
  long_press_action = system:/usr/local/bin/reboot.sh
  
  # Action for releasing the button after a long press is to toggle the value of GPIO 6.
  long_press_release_action = gpiotoggle:6
  

• Configures GPIO 4 as input:

  • Enables the pull-up resistor on start

  • Runs the mpd next command on a short press (falling)

  /etc/mygpiod.d/4.in

  # Configuration file for GPIO 4 as input
  # Request the falling event
  event_request = falling
  
  # Enable the internal pull-up resistor
  bias = pull-up
  
  # Use libmpdclient to connect to mpd and send the command `next`
  action_falling = mpc:next
  

• Configures GPIO 5 as output:

  • Sets the value to active on start

  /etc/mygpiod.d/5.out

  # Configuration file for GPIO 5 as output
  # Set the GPIO to active
  value = active
  

• Configures GPIO 6 as output:

  • Sets the value to inactive on start

  /etc/mygpiod.d/6.out

  # Configuration file for GPIO 6 as output
  # Set the GPIO to inactive
  value = inactive
  

• Configures GPIO 7 as input:

  • Enables the pull-up resistor on start

  • Enabled the long press action for falling event

  • Increases the mpd volume by 5 % after 100 ms and each 500 ms as long the button is pressed

  /etc/mygpiod.d/7.in

  # Configuration file for GPIO 7 as input
  # Request the falling event
  event_request = falling
  
  # Enable the internal pull-up resistor
  bias = pull-up
  
  # Enable long press action for the falling event
  long_press_event = falling
  
  # Set initial long press timeout to 100 ms
  long_press_timeout = 100
  
  # Set interval to 500 ms, action is repeated in this interval until the value changes again
  long_press_interval = 500
  
  # Use libmpdclient to connect to mpd and send the command `volume +5`
  # This increases the volume by 5 percent
  long_press_action = mpc:volume +5
  

• Configures GPIO 8 as input:

  • Enables the pull-up resistor on start

  • On falling event:

    • Set GPIO 6 for 1000 ms to active

    • Execute the Jukebox script through the myGPIOd API

  /etc/mygpiod.d/8.in

  # Configuration file for GPIO 8 as input
  # Request the falling event
  event_request = falling
  
  # Enable the internal pull-up resistor
  bias = pull-up
  
  # Execute the Jukebox script through the myGPIOd API
  action_falling = gpioblink:6 1000 0
  action_falling = mympd:https://127.0.0.1 default Jukebox
  

• Rotary Encoder configuration:

  • Configure GPIO 5 as input and connect it to the CLX pin

  • Configure GPIO 6 as input and connect it to the DT pin

  • Disable internal resistors

  • On rising event of GPIO 5 execute a Lua script that reads the value of GPIO 6

  /etc/mygpiod.d/5.in

  event_request = rising
  bias = disable
  debounce = 5000
  action_rising = lua:rotaryEncoder
  

  /etc/mygpiod.d/5.in

  event_request = none
  bias = disable
  debounce = 5000
  

  /etc/mygpiod.lua

  function rotaryEncoder()
    -- Get value of the DT pin
    local _, dt  = gpioGet(6)
    -- Determine rotation direction
    if dt == "active" then
        print("counter-clockwise")
    else
        print("clockwise")
    end
  end