Flix

An Elixir client for the Flic button.

What's in the name?

The name Flix is the result of combining Fli(c), the name of the button, and (e)x, the extension used by Elixir source files.

Flix is also a town in the beautiful province of Tarragona, Catalonia, Spain.

The Flic protocol

Flix implements the full Flic protocol as per described in the official fliclib-linux-hci GitHub repository.

Usage

Flic buttons don't connect directly to Flix nor the other way around. Flic buttons connect to a flicd via bluetooth. Flix applications also connect to flicd but via a TCP. See the diagram below.

+------------+  command(s)  +---------+               +---------------+
|            +------------->|         |               |               |
|  Flix App  |     TCP      |  flicd  |<--------------+  Flic Button  |
|            |<-------------+         |   Bluetooth   |               |
+------------+   event(s)   +---------+               +---------------+

You can find more information about Flic's flicd in its official page.

Writing a Flix application is as simple as defining a new Elixir module, using Flix's __using__ macro (ie. use Flix) and implementing Flix's handle_event/2 callback function.

defmodule MyFlixApp do
  use Flix

  def handle_event(event, state) do
    new_state = do_something(event, state)
    {:ok, new_state}
  end
end

Below is a full example of a Flix application where a counter is initialised to 0 and increased or decreased by one when someone does single- or double-clicks a Flic button, respectively. The code makes the following assumptions:

flicd is running and reachable on raspberrypi.local:5551.
The Flic button (ie. "80:E4:DA:78:45:1B") has already been paired with flicd.

defmodule Flix.Examples.Counter do
  use Flix

  alias Flix.Protocol.Events.ButtonSingleOrDoubleClickOrHold
  alias Flix.Protocol.Enums.ClickType

  def start(host \\ 'raspberrypi.local', port \\ 5551) do
    {:ok, client} = Flix.start(__MODULE__, 0, host, port)
    :ok = set_up(client)
    {:ok, client}
  end

  def start_link(host \\ 'raspberrypi.local', port \\ 5551) do
    {:ok, client} = Flix.start_link(__MODULE__, 0, host, port)
    :ok = set_up(client)
    {:ok, client}
  end

  def set_up(client) do
    :ok = Flix.create_connection_channel(client, "80:E4:DA:78:45:1B", 1)
  end

  def stop(client) do
    :ok = Flix.stop(client)
  end

  def handle_event(
    %ButtonSingleOrDoubleClickOrHold{click_type: ClickType.SingleClick},
    count
  ) do
    new_count = count + 1
    IO.puts "Count = #{new_count}"
    {:ok, new_count}
  end
  def handle_event(
    %ButtonSingleOrDoubleClickOrHold{click_type: ClickType.DoubleClick},
    count
  ) do
    new_count = count - 1
    IO.puts "Count = #{new_count}"
    {:ok, new_count}
  end
  def handle_event(event, count) do
    require Logger
    Logger.debug("No handle_event/2 clause in #{__MODULE__} for #{inspect(event)}")
    {:ok, count}
  end
end

Author(s)

Enrique Fernandez <efcasado@gmail.com>

Acknowledgements

I would like to thank BlueLabs for sponsoring the development of Flix by creating an opportunity for me to work on this project.

This project was conceived during BlueLabs' 2nd Hackathon (22-23 July, 2021).

License

The MIT License (MIT)

Copyright (c) 2021, Enrique Fernandez

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.