bluetoothle | cross platform , REACTIVE BluetoothLE Plugin

I'm working with an ESP32 chip and am trying to create an Android app (using Ionic) which allows user to send wifi credentials to the ESP32 chip via BLE. I'd like to be able to update the status of the wifi sending process for the user in the UI (which I'm developing using Angular and then converting it to an Android webapp using Ionic). To do this, I'm also using the capacitor-community/bluetooth-le library.

Can anyone explain to me what this.queue does in the async write function (code shown below) does? I thought this function returns a response from a remote BLE device after writing to a GATT characteristic, but I get absolutely nothing at all for a response.

Before we even start: In researching this problem I've looked at dozens of posts here and elsewhere, and realize that VB is the worst for Bluetooth programming. However, this is for a client who has a massive legacy VB system and I have no choice.

According to MS documentation, the BluetoothLEDevice.FromIdAsync is supposed to return a BluetoothLEDevice object but on my system it returns a generic System.__ComObject that I can't cast to a BluetoothLEDevice. I have tried Cast and DirectCast but neither work. The sample C++ code I've looked at doesn't require any type of casting; the variable is declared and set using the BluetoothLEDevice.FromIdAsync function without any dramas.

Here is my test code.

First of all, Sorry for my bad English. I'm studying about BluetoothLE under the UWP. Now, I can pair with my Bluetooth Low-Energy device and i can get services. And then, I want to get the all characteristics from my Bluetooth(LE) device.

I can get all service's characteristics except Human Interface Device(HID)'s characteristics. Below is the code get the characteristic( when change the service in combobox event)

I am new to this business and I want to make an application related to Bluetooth LE. I don't know where to start, I want to do it using a library. I searched libraries such as 32feet.Net, InTheHand.BluetoothLe, Plugin.BluetoothLe, ble.net but I could not figure out how to make a windows form app or what can I do and where to start. Can anyone help?

I've set up a UWP sample BluetoothLE server using the code provided here. I'm using LightBlue on my iPhone as a client to read/write data to the characteristics exposed by the server.

Here's a description of the service:

This scenario allows the system to publish a calculator service. Remote clients (including this sample on another machine) can supply 2 operands and an operator and get a result.

Valid range for Operand is integer values. Valid range for Operator is 1-4 corresponding to +,-,*,/ respectively.

So there are 3 write characteristics, and 1 read characteristic. Using LightBlue on my iPhone, I write data to the operand characteristics in hexadecimal format, however I'm a little confused.

I expected to write the hexadecimal representation of a 32 unsigned integer, eg:

I am trying to create a Xamarin.Forms app that will run on both iOS and Android. Eventually I need instances of the app to communicate with each other via Bluetooth, but I'm stuck on getting the iOS side to do anything with Bluetooth. I originally tried to work with Plugin.BluetoothLE and Plugin.BLE, but after a week and a half I was not able to get advertising or scanning to work on either OS with either plugin, so I decided to try implementing simple Bluetooth interaction using the .NET wrappers of the platform APIs, which at least are well documented. I did get scanning to work fine on the Android side. With iOS, though, what I have right now builds just fine, and runs on my iPad without errors, but the DiscoveredPeripheral handler is never called, even though the iPad is just a few inches from the Android tablet and presumably should be able to see the same devices. I have verified this by setting a breakpoint in that method, which is never reached; and when I open the Bluetooth Settings on the iPad to make it discoverable the app version on the Android tablet can see it, so I don't think it's an iPad hardware issue.

It seems obvious that there is simply some part of the process I don't know to do, but it's not obvious (to me) where else to look to find out what it is. Here is the code for the class that interacts with the CBCentralManager (as far as I understand from what I've read, this should include everything necessary to return a list of peripherals):

This is how I call this. to resize window of the app

I have an application scanning BluetoothLE devices (temperature). The application is whitelisted in the list for battery optimizations and uses a PARTIAL_WAKE_LOCK.

It works like a charm with a Zebra TC25 Android 7.1.2 using a thread scanning BLE devices every 10 minutes independently of the android device state.

However the same application does not work at all with a samsung galaxy S10+ Android 10 when the screen is off (it works when screen is on). I know that the simple thread method will not work because of doze mode. So I also tried these ways :

setExactAndAllowWhileIdle(TJAlarmManager.JavaClass.RTC_WAKEUP, time,PendingIntent) and firebase cloud messaging sending high priority message. Alarm method has limitations but fcm has not as far as I know.

These 2 ways also failed. The fcm message is received and the alarm triggers, both run the BLEDiscover procedure below to run a bluetooth scan, but no bluetooth device are discovered.

Here is what happens in two situations. In the fisrt one, the screen is on, it always works :

I'm trying to send data between two phones (e.g. two iPhones, or maybe even cross platform) via bluetooth.

I've been trying to use Plugin.BluetoothLE from NuGet, which appears to have been updated recently (March 2020), however I can't seem to get any of the sample code working (details below).

I'd be grateful if anyone can point out what's wrong below, and/or if there's a better way of sending data between two phones through bluetooth. My application is time dependent, and there may not be a wifi network, so bluetooth seems to be the best option...

When I implement the demo server code available at https://github.com/aritchie/bluetoothle, I get the following errors:

No 'AddService' method within CrossBleAdapter.Current.CreateGattServer().

No 'Start' method within CrossBleAdapter.Current.CreateGattServer().

Here's the code I'm using (which I'm calling from the form).