A blinking LED using GenServer

blinky_gen.exs

defmodule Blinky do
  use GenServer
  alias ElixirALE.GPIO

  @duration 2000

  def start_link(state \\ %{on: true, pid: nil}) do
    GenServer.start_link(__MODULE__, state, name: __MODULE__)
  end

  def init(%{on: is_on, pid: _pid}) do
    {:ok, pid} = GPIO.start_link(23, :output)
    schedule_toggle()
    {:ok, %{on: is_on, pid: pid}}
  end

  def handle_info(:toggle, %{on: true, pid: pid}) do
    GPIO.write(pid, 1)
    schedule_toggle()
    {:noreply, %{on: false, pid: pid}}
  end

  def handle_info(:toggle, %{on: false, pid: pid}) do
    GPIO.write(pid, 0)
    schedule_toggle()
    {:noreply, %{on: true, pid: pid}}
  end

  def schedule_toggle() do
    Process.send_after(self(), :toggle, @duration)
  end

end