Pigpio - Using Erlang for GPIO on a Raspberry Pi

Using Erlang for GPIO on a Raspberry Pi with http://abyz.me.uk/rpi/pigpio/

⚠️ This library is still very much in a WORK IN PROGRESS state and for my personal use. I'm currently integrating it in one of my pet projects and refinements will be added later.

🐞 Prerequisites

Nothing should be running on port 8888, that's where we'll run the pigpio tcp server.

🚀 Getting started

Add the following to your Makefile

DEPS = pigpio
dep_pigpio = git https://github.com/mmalmsten/pigpio.git

Install pigpio on your Raspberry pi

sudo apt-get install pigpio python-pigpio python3-pigpio

Start the pigpio daemon (tcp server)

sudo pigpiod

🛰 Usage

Start a genserver for the gpio pin

{ok, Pid} = pigpio:start_link(Gpio_pin)

Examples:

Set pin mode to input

ok = pigpio:cast(Pid, {command, setmode, 0}).

Read from the pin once and store in genserver state

ok = pigpio:cast(Pid, {read, once}).

Read from the pin every N millisecond and store in genserver state

ok = pigpio:cast(Pid, {read, N}).

Get the latest reading from pin

Reply = pigpio:call(Pid, read).

Register an LED 💡

led(Gpio) ->
    {ok, Pid} = pigpio:start_link(Gpio),
    gen_server:cast(Pid, {command, setmode, 1}),
    {ok, Pid}.

{ok, Pid} = led(?GPIO_PIN).

pigpio:cast(Pid, {command, setpullupdown, 1}). % On

pigpio:cast(Pid, {command, setpullupdown, 0}). % Off

Register a button 🔘

button(Gpio) ->
    {ok, Pid} = pigpio:start_link(Gpio),
    pigpio:cast(Pid, {command, setmode, 0}),
    pigpio:cast(Pid, {command, setpullupdown, 2}),
    {ok, Pid}.

{ok, Pid} = button(?GPIO_PIN).

Status = pigpio:call(Pid, read).

TODO:

• Add possibility to add a listener to a pin and update current status in genserver state
• Tests