Hello! I’m currently building a weather station with sensors for wind, rain and temperature in elixir with Circuits.GPIO lib.

So far it has been a blast but I’ve gotten stuck on reading two sensors (eg buttons) and I assume it’s because the functional nature of elixir. My code:

defmodule WeatherStation do
  use GenServer
  require Logger

  @wind_sensor_pin 5
  @rain_sensor_pin 6

  def start_link(_opts) do
    GenServer.start_link(__MODULE__, [], name: __MODULE__)
  end

  def init(_opts) do
    {:ok, _gpio} = Circuits.GPIO.open(@rain_sensor_pin, :input)
    {:ok, gpio} = Circuits.GPIO.open(@wind_sensor_pin, :input)

    Circuits.GPIO.set_interrupts(gpio, :falling)
    {:ok, gpio}
  end

  def handle_info({:circuits_gpio, @rain_sensor_pin, _timestamp, _value}, state) do
    # handle stuff
  end

Obviously above don’t work (button presses is not sent) as I intended so my question is how to organize your code when you have more than one button/sensor in the GPIO lib.

Should I have a genserver for each sensor?