https://github.com/connorrigby/elixir-rf69

Elixir driver for RFM69HCW radio
https://github.com/connorrigby/elixir-rf69

circuits elixir nerves radio rf69

Last synced: 3 months ago
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Elixir driver for RFM69HCW radio

• Host: GitHub
• URL: https://github.com/connorrigby/elixir-rf69
• Owner: ConnorRigby
• License: apache-2.0
• Created: 2020-05-27T02:39:01.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2022-03-18T21:18:41.000Z (almost 3 years ago)
• Last Synced: 2024-06-11T21:56:02.119Z (7 months ago)
• Topics: circuits, elixir, nerves, radio, rf69
• Language: Elixir
• Homepage:
• Size: 52.7 KB
• Stars: 7
• Watchers: 3
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# RF69HCW Elixir Interface

Interact with RFM69HCW radio modules via spi.

[datasheet](https://cdn.sparkfun.com/datasheets/Wireless/General/RFM69HCW-V1.1.pdf)

[Arduino compatible library](https://github.com/LowPowerLab/RFM69)

[Purchase from adafruit](https://www.adafruit.com/product/3070)

[Purchase from SparkFun](https://www.sparkfun.com/products/12775)

## Current Features / Known Issues / wants

* [x] Packet encryption/decryption

* [x] Send packets

* [x] Receive packets

* [x] Auto Ack packets

* [x] Support other frequencies

* [x] AES encryption

* [x] Basic Usage documentation

* [x] RSSI value reading

* [x] Processing packet data outside of the library

* [ ] Packet recv/send telemetry (because why not?)

* [ ] Unit tests?

## WARNINGS

Be sure to check your local laws for legal radio bands.

## Compatability

Packets are encoded/decoded with the same format as

LowPowerLabs RF69 library version 1.4 ([described here](https://lowpowerlab.com/2019/05/02/rfm69-10bit-node-addresses/)).

The goal is to have feature parity with the Arduino library.

## Wiring

Currently i've only tested on Raspberry Pi, but it should work

on any device that [ElixirCircuits](https://elixir-circuits.github.io/) supports.

## Usage

```elixir

iex()> {:ok, pid} = RF69.start_link [

  reset_pin: 16,

  ss_pin: 25,

  irq_pin: 13,

  spi_bus_name: "spidev0.0",

]

{:ok, #PID<0.1660.0>}

iex()> receive do

...()>  %RF69.Packet{} = packet ->

...()>  IO.inspect(packet, label: "received packet")

...()>  :ok

...()> end

packet received: %RF69.Packet{

  ack_requested?: true,

  is_ack?: false,

  payload: "123 ABCDEFGHIJK",

  rssi: -42,

  sender_id: 2,

  target_id: 1

}

:ok

iex()> RF69.send(pid, 2, "hello node 2 from gateway node!")

:ok

iex()> 

```

## Examples

The API defined is pretty low level. If you want to use it, you should probably

wrap the radio server in your own genserver. See the [`Logger` Example](lib/rf69/logger_receiver.ex)

for an example.

[There is a repo here](https://github.com/ConnorRigby/elixir-rf69-examples) with some more examples

## Acking

By default the rf69 server will respond to acks If your implementation requires user acking, when starting

the rf69 server, pass in `auto_ack?: false`.

This will require that in your code when you receive a packet, you will be responsible for acking it in

the configured amount of time required by your other nodes. Here's an example:

```elixir

def handle_info(%Packet{requires_ack?: true} = packet, state) do

  # Process the packet (whatever that means to your application)

  case process_packet(packet) do

    :ok -> 

      # packet processed successfully.

      RF69.ack(state.rf69, packet)

    :error -> 

      # packet processed unsuccessfully.

      # The protocol has no concept of "nack"ing, so the lack of

      # an ack should be considered a "nack"

      Logger.error "Not acking #{inspect(packet)}"

  end

  {:noreply, state}

end

```

## Encryption

AES Encryption is handled at the hardware level. All you as a developer need to

do is load the encryption key when starting the server.

> WARNING:

> This key must be **EXACTLY** 16 bytes wide.

```elixir

{:ok, pid} = RF69.start_link(encrypt_key: "sampleEncryptKey")

```