Execute GPIO functions on the production server.

firmware/lib/firmware/application.ex

@@ -21,11 +21,10 @@ defmodule Firmware.Application do
 
   # List all child processes to be supervised
   def children(:host) do
-    [
-      # Children that only run on the host
-      # Starts a worker by calling: Firmware.Worker.start_link(arg)
-      # {Firmware.Worker, arg},
-    ]
+    {:ok, _} = Node.start(:"host@0.0.0.0")
+    Node.set_cookie(:testcookie)
+    true = Node.connect(:"esrom@nerves.local")
+    []
   end
 
   def children(_target) do

firmware/mix.exs

@@ -63,7 +63,7 @@ defmodule Firmware.MixProject do
   def release do
     [
       overwrite: true,
-      cookie: "#{@app}_cookie",
+      cookie: "testcookie",
       include_erts: &Nerves.Release.erts/0,
       steps: [&Nerves.Release.init/1, :assemble]
     ]

morse/lib/morse/worker.ex

@@ -1,6 +1,4 @@
 defmodule Morse.Worker do
-  alias Circuits.GPIO
-
   @moduledoc """
   Functions to control the signal lamp connected with GPIO.
   """
@@ -24,32 +22,31 @@ defmodule Morse.Worker do
 
     update_progress(0, 100)
 
-    {:ok, gpio} = GPIO.open(relay_pin(), :output)
-    GPIO.write(gpio, @off)
+    toggle_lamp(@off)
     Process.sleep(@sleep_start)
 
     code
     |> Enum.with_index()
-    |> Enum.each(&signal_symbol(gpio, &1, code_length))
+    |> Enum.each(&signal_symbol(&1, code_length))
 
     update_progress(100, 100)
   end
 
-  defp signal_symbol(gpio, {?., _index}, _length) do
-    GPIO.write(gpio, @on)
+  defp signal_symbol({?., _index}, _length) do
+    toggle_lamp(@on)
     Process.sleep(@sleep_short)
-    GPIO.write(gpio, @off)
+    toggle_lamp(@off)
     Process.sleep(@sleep_delay)
   end
 
-  defp signal_symbol(gpio, {?-, _index}, _length) do
-    GPIO.write(gpio, @on)
+  defp signal_symbol({?-, _index}, _length) do
+    toggle_lamp(@on)
     Process.sleep(@sleep_long)
-    GPIO.write(gpio, @off)
+    toggle_lamp(@off)
     Process.sleep(@sleep_delay)
   end
 
-  defp signal_symbol(_gpio, {?\s, index}, length) do
+  defp signal_symbol({?\s, index}, length) do
     Process.sleep(@sleep_pause)
     update_progress(index, length)
   end
@@ -58,12 +55,27 @@ defmodule Morse.Worker do
     Morse.Server.update_progress(index / length * 100)
   end
 
-  defp relay_pin() do
-    Application.fetch_env!(:morse, :relay_pin)
-  end
-
   defp secret_code do
     Application.fetch_env!(:morse, :morse_message)
     |> String.to_charlist()
   end
+
+  case Mix.Nerves.Utils.mix_target() do
+    :host ->
+      def toggle_lamp(state) do
+        :rpc.call(:"esrom@nerves.local", Morse.Worker, :toggle_lamp, [state])
+      end
+
+    _ ->
+      alias Circuits.GPIO
+
+      def toggle_lamp(state) do
+        {:ok, gpio} = GPIO.open(relay_pin(), :output)
+        GPIO.write(gpio, state)
+      end
+
+      defp relay_pin() do
+        Application.fetch_env!(:morse, :relay_pin)
+      end
+  end
 end

ui/lib/ui_web/channels/user_socket.ex

@@ -32,7 +32,6 @@ defmodule UiWeb.UserSocket do
   def id(_socket), do: nil
 
   def broadcast_progress(progress) do
-    IO.puts("in user socket!")
     UiWeb.Endpoint.broadcast("morse:progress", "update", %{value: progress})
   end
 end