Button

ピンを開く

{:ok, led} = Circuits.GPIO.open("GPIO17", :output)
{:ok, btn} = Circuits.GPIO.open("GPIO18", :input)

LED の点灯

Circuits.GPIO.write(led, 1)

Circuits.GPIO.write(led, 0)

ボタンのON/OFF入力

Circuits.GPIO.read(btn)

ピンを閉じる

Circuits.GPIO.close(led)
Circuits.GPIO.close(btn)

ボタンとLEDの連動

defmodule LEDButton do
  use GenServer

  require Logger

  alias Circuits.GPIO

  @btn "GPIO18"
  @led "GPIO17"

  def start_link(frame) do
    GenServer.start_link(__MODULE__, %{frame: frame}, [])
  end

  def init(state) do
    {:ok, btn} = GPIO.open(@btn, :input, pull_mode: :pullup)
    GPIO.set_interrupts(btn, :both)

    {:ok, led} = GPIO.open(@led, :output)

    {:ok, %{btn: btn, led: led, frame: state.frame}}
  end

  def handle_info({:circuits_gpio, @btn, _timestamp, value}, state) do
    Kino.Frame.render(state.frame, value)

    GPIO.write(state.led, value)

    {:noreply, state}
  end

  def handle_info(:stop, state) do
    Circuits.GPIO.close(state.led)
    Circuits.GPIO.close(state.btn)

    {:stop, "stopped", state}
  end
end

frame = Kino.Frame.new()

{:ok, pid} = LEDButton.start_link(frame)

GenServer.stop(pid)