Bluetooth support for Raspberry Pi Zero W

[angrycandy]

Environment

• Elixir version (elixir -v):

Erlang/OTP 24 [erts-12.0.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]

Elixir 1.12.0 (compiled with Erlang/OTP 24)

• Nerves environment: (mix nerves.env --info)

==> nerves
==> firmware
|nerves_bootstrap| Environment Package List

  Pkg:         nerves_toolchain_ctng
  Vsn:         1.8.3
  Type:        toolchain_platform
  BuildRunner: {nil, []}

  Pkg:         nerves_toolchain_armv6_nerves_linux_gnueabihf
  Vsn:         1.4.2
  Type:        toolchain
  BuildRunner: {Nerves.Artifact.BuildRunners.Local, []}

  Pkg:         nerves_system_br
  Vsn:         1.16.0
  Type:        system_platform
  BuildRunner: {nil, []}

  Pkg:         nerves_system_rpi0
  Vsn:         1.16.0
  Type:        system
  BuildRunner: {Nerves.Artifact.BuildRunners.Local, []}

|nerves_bootstrap| Loadpaths Start


Nerves environment
  MIX_TARGET:   rpi0
  MIX_ENV:      dev

|nerves_bootstrap| Environment Variable List
  target:     rpi0
  toolchain:  /home/bfw/.nerves/artifacts/nerves_toolchain_armv6_nerves_linux_gnueabihf-linux_x86_64-1.4.2
  system:     /home/bfw/.nerves/artifacts/nerves_system_rpi0-portable-1.16.0
  app:        .

|nerves_bootstrap| Loadpaths End

• Additional information about your host, target hardware or environment that
  may help

NA

Current behavior

There is no UART for Bluetooth.

iex(1)> cmd "ls /dev/ttyA*"
/dev/ttyAMA0
0
iex(2)>

Expected behavior

https://hexdocs.pm/blue_heron_transport_uart/readme.html

BlueHeron supports UART-based Bluetooth modules. Currently, this ONLY includes the Cypress Semiconductor BCM43438. This part is on the Raspberry Pi Zero W and the Raspberry Pi 3 B. It is NOT on the 3 B+.

https://hexdocs.pm/nerves_system_rpi0/readme.html#linux-kernel-configuration-notes

In Networking support, disable Amateur Radio support, CAN bus subsystem, IrDA subsystem, Bluetooth, WiMAX, Plan 9, and NFC. (TBD - this may be too harsh, please open issues if you're using any of these and it's the only reason for you to create a custom system.)

[fhunleth]

Try "/dev/ttyS0".

I don't use BLE, but I've been told that people have gotten it working. Some people modify the config.txt to swap ttyAMA0 and ttyS0 for higher speeds.

[angrycandy]

"/dev/ttyS0" worked for me. Logger.add_backend(BlueHeron.HCIDump.Logger) shows:

No.	Time	Source	Destination	Protocol	Length	Info
1	0.000000	host	controller	HCI_CMD	4	Sent Reset
2	0.000000	controller	host	HCI_EVT	7	Rcvd Command Complete (Reset)
3	0.000000	host	controller	HCI_CMD	4	Sent Read Local Version Information
4	0.000000	controller	host	HCI_EVT	15	Rcvd Command Complete (Read Local Version Information)
5	0.000000	host	controller	HCI_CMD	4	Sent Read Local Name
6	0.000000	controller	host	HCI_EVT	255	Rcvd Command Complete (Read Local Name)

I don't understand swap ttyAMA0 and ttyS0 for higher speeds. I'm using ttyS0 at 115_200. Is ttyAMA0 faster?

[fhunleth]

I'm glad it's working! Let's not change anything. :)

Here's the story on the UART. There are two UARTs on the Raspberry Pis, ttyAMA0 and ttyS0. On most hardware UART connections are fixed, but the Raspberry Pi is special and you can switch whether ttyAMA0 is connected to the UART pins or Bluetooth. ttyS0 is connected to the other one. This is done with the config.txt. Unfortunately, the UARTs aren't the same so there are tradeoffs. ttyAMA0 is the better one. Here's more info: https://www.raspberrypi.org/documentation/computers/configuration.html#pl011-and-mini-uart.

Unless you run into performance issues with whatever you're doing with Bluetooth, I'd stick with ttyS0.

[angrycandy]

I'm adding more information here to support #227 using An example scanner to collect Manufacturer Specific Data.

Raspberry Pi Zero W results:

iex(1)> {:ok, pid} = BlueHeronScan.start_link(:uart, %{device: "ttyS0"})
{:ok, #PID<0.10860.0>}
iex(2)> state = :sys.get_state(pid)
%{
  ctx: #BlueHeron.Context<0.10861.0>,
  devices: %{
    4753574963174 => %{
      272 => <<64, 10, 1, 0>>,
      :name => "Bose AE2 SoundLink",
      :time => ~U[2021-09-27 14:48:25.778174Z]
    },
    48660401950223 => %{
      784 => <<64, 16, 2, 48>>,
      :name => "LE-Bose Revolve SoundLink",
      :time => ~U[2021-09-27 14:48:25.658670Z]
    },
    110946934216995 => %{
      117 => <<66, 4, 1, 128, 102, 100, 231, 216, 154, 89, 35, 102, 231, 216,
        154, 89, 34, 1, 62, 0, 0, 0, 0, 0>>,
      :time => ~U[2021-09-27 14:48:25.873323Z]
    },
    181149778439893 => %{
      1 => <<1, 1, 4, 28, 196, 90>>,
      :name => "GVH5102_EED5",
      :time => ~U[2021-09-27 14:48:26.032518Z]
    },
    181149781445015 => %{
      name: "ihoment_H6182_C997",
      time: ~U[2021-09-27 14:48:26.059225Z]
    },
    246390811914386 => %{
      60552 => <<0, 97, 10, 12, 22, 100, 2>>,
      :name => "Govee_H5074_F092",
      :time => ~U[2021-09-27 14:48:24.429195Z]
    }
  },
  ignore_cids: [6, 76],
  working: true
}
iex(3)> BlueHeronScan.ignore_cids(pid, MapSet.new([6, 76, 117, 784]))
{:ok, #MapSet<[6, 76, 117, 784]>}
iex(4)> BlueHeronScan.clear_devices(pid)
:ok
iex(5)> state = :sys.get_state(pid)
%{
  ctx: #BlueHeron.Context<0.10861.0>,
  devices: %{
    4753574963174 => %{
      272 => <<64, 10, 1, 0>>,
      :name => "Bose AE2 SoundLink",
      :time => ~U[2021-09-27 14:48:46.192324Z]
    },
    181149778439893 => %{
      1 => <<1, 1, 4, 28, 196, 90>>,
      :name => "GVH5102_EED5",
      :time => ~U[2021-09-27 14:48:46.287562Z]
    },
    181149781445015 => %{
      name: "ihoment_H6182_C997",
      time: ~U[2021-09-27 14:48:47.139443Z]
    },
    246390811914386 => %{
      60552 => <<0, 94, 10, 11, 22, 100, 2>>,
      :name => "Govee_H5074_F092",
      :time => ~U[2021-09-27 14:48:45.477457Z]
    }
  },
  ignore_cids: #MapSet<[6, 76, 117, 784]>,
  working: true
}
iex(6)> BleAdMfgData.print(state.devices)
[
  ["26.5˚C 56.4% RH 100%🔋", "Govee_H5074_F092"],
  ["27.0˚C 50.8% RH 90%🔋", "GVH5102_EED5"]
]
iex(7)> BlueHeronScan.disable(pid)
:ok
iex(8)> BlueHeronScan.clear_devices(pid)
:ok
iex(9)> state = :sys.get_state(pid)
%{
  ctx: #BlueHeron.Context<0.10861.0>,
  devices: %{},
  ignore_cids: #MapSet<[6, 76, 117, 784]>,
  working: true
}
iex(10)> BlueHeronScan.enable(pid)
:ok
iex(11)>