drama999 / littlebluetooth

A simple library that helps you in connecting with BLE devices

Hello there 👋

• ☠️ Biomedical Engineer
• 🧑‍💻 Self taught Programmer
• 🤓 Tinkerer ⚡️🪛⚙️🖥
• 📱 More than 4 apps on AppStore as Indie Developer
• 📝 I also write on Medium
• 🔭 I’m currently working on a device to improve boxers 🥊 reflexes

littlebluetooth's Issues

Can I suppress debug output?

When I use LittleBlueTooth to communicate with a device periodically, the combine debug print fills up the console.
Is it possible to turn on/off the debug output?

Demo app

Can you add a demo app?

IOS-CoreBluetooth-Mock dependency breaks SwiftUI previews in Xcode 12.5

There is a fix for that but it hasn't been released: NordicSemiconductor/IOS-CoreBluetooth-Mock#37

Otherwise, SwifUI previews don't work now because of this in Xcode 12.5. Probably, tests, too.

Using startListen on more than 1 characteristic at once fails with characteristicNotFound

I have something like this

func getSpeed() -> AnyPublisher<SpeedState, LittleBluetoothError> {
    littleBT.startListen(from: Self.SPEED_CHARACTERISTIC)
      .prepend(littleBT.read(from: Self.SPEED_CHARACTERISTIC))
      .handleEvents(receiveCompletion: { completion in
        switch completion {
          case .finished:
            break

          case .failure(let error):
            log.error("SPEED_CHARACTERISTIC read/listen failed with error: \(error)")
        }
      })
      .eraseToAnyPublisher()
  }

  func getBattery() -> AnyPublisher<BatteryState, LittleBluetoothError> {
    littleBT.startListen(from: Self.BATTERY_CHARACTERISTIC)
      .prepend(littleBT.read(from: Self.BATTERY_CHARACTERISTIC))
      .handleEvents(receiveCompletion: { completion in
        switch completion {
          case .finished:
            break

          case .failure(let error):
            log.error("BATTERY_CHARACTERISTIC read/listen failed with error: \(error)")
        }
      })
      .eraseToAnyPublisher()
  }

If I subscribe to just one of these (no matter which one) at once, it works just fine. If, on the other hand, I do something like

Publishers.CombineLatest(
          bikeRepository.getSpeed(),
          bikeRepository.getBattery()
)

And subscribe to that, one of the subscriptions will immediately fail with characteristicNotFound

I was thinking of using the flow similar to what kable does (https://github.com/JuulLabs/kable). There, you can easily do:

   override fun getBattery(): Flow<Metric> = peripheral
        .observe(BATTERY_CHARACTERISTIC)
        .map { it.asBatteryMetric() }

    override fun getSpeed(): Flow<Metric> = peripheral
        .observe(SPEED_CHARACTERISTIC)
        .map { it.asSpeedMetric() }

And then

override fun getMetrics(): Flow<List<Metric>> = combine(
        getSpeed(),
        getBattery
    ) { speed, battery ->
      // do something, like create a model containing all the metrics
    }

This library actually has iOS support through KMM, so this is what observe does: https://github.com/JuulLabs/kable/blob/main/core/src/appleMain/kotlin/Peripheral.kt

LittleBlueTooth#startListen behavior

First of all, great work on the library. I've just started with it and it's looking great!

I have a question though. When using LittleBlueTooth#startListen, I don't receive an initial value. Is this by design?

For example:
littleBT.read(from: Self.BATTERY_CHARACTERISTIC) will publish a value as soon as I subscribe
but
littleBT.startListen(from: Self.BATTERY_CHARACTERISTIC) will not publish anything as soon I subscribe

Discovering services

Not really an issue; but more on the usage.

How do you use this to discover services and characteristics after finding the peripheral with discovery?

Thanks!

List of services

Hello!
how can i scan the list of available services?

Thank you