使用iOS SDK中的BLE从外部设备发送和接收数据

Question

I have to fetch the data from the external device (Datalogger Thermometer) using BLE. Please see the below image for this device.

This device is only sending data when we are sending one command. I mean we have to send static byte data to device first, then and then it will be sending back the data of T1, T2, T3 and T4 values which is showing into the image.

I can able to sending data using BLE to one iOS device to another using BTLE Central Peripheral Transfer Demo and this answer . But, I can not able to send and receive data to this external device using this way.

As mentioned into this demo, I am using CBPeripheralManager and CBCentralManager for sending and receiving data using BLE. Also I can able to show the list of all near by BLE connections using EAAccessoryManager . So when user click on the any device from the list, then I fetching UUID of that device and trying to sending and receiving data using that UUID.

Is there any other way to sending and receiving data using Bluetooth to iOS device to any external device.?

I would like to share that, Android Developer has implement this into Android using SSP, not BLE. Is this possible to do this using BLE in iOS.?

Any help would be appreciated.

Answer 1

I always use the CoreBluetooth implementing this protocols (CBCentralManagerDelegate,CBPeripheralDelegate) and overriding this methods:

func centralManagerDidUpdateState(_ central: CBCentralManager)

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber)

func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral)

func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?)

func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?)

// Check if the service discovered is a valid Service
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?)

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?)

// And for getting the value changes in the BLE Device...
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?)

func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?)

I hope it helps

Answer 2

Before you write or read values, you need to know which characteristic is readable and which is writeable, than you can read or write it. Simply the process of BTLE is:

scan peripheral -> conenect -> find services -> discover characteristics -> ...operations you need

if you want to write value to writeable characteristics, you need confirm that peripheral will response this write request, otherwise you will receive a error in callback: peripheral(_:didWriteValueFor:error) maybe "Unknow error".

other when you try to read value of characteristics you need call: readValue(for:) or setNotifyValue(_:for:) , the results of peripheral's update will response in peripheral(_:didUpdateValueFor:error:)

Above, is my understanding of BTLE data transfer. hope to help you.