Find your accessory with Bluetooth Channel Sounding

3:43 - Start a Core Bluetooth Channel Sounding session

import CoreBluetooth

func isChannelSoundingSupported() -> BOOL {
    guard centralManager.state == .poweredOn else { return }
    if #available(iOS 27.0, *) {
        // Check current device supports Bluetooth Channel Sounding
        return CBCentralManager.supportsFeatures(.channelSounding)
    }
}

func startChannelSounding(_ peripheral: CBPeripheral) {
    guard peripheral.isConnected else { return }
    if #available(iOS 27.0, *) {  
        // Step 1: Create a CBChannelSoundingSessionConfiguration
        let config = CBChannelSoundingSessionConfiguration(role: .initiator)

        // Step 2: Start the channel sounding session
        peripheral.startChannelSoundingSession(config)
    }
}

4:09 - Receive distance results and cancel a session

import CoreBluetooth

// Receive distance results
func peripheral(_ peripheral: CBPeripheral,
                didReceive results: CBChannelSoundingProcedureResults?,
                error: Error?) {
    guard let results = results else { return }

    let distance = results.distance
    
    // Do something with distance
}

// Cancel a Channel Sounding session
func cancelChannelSounding(_ peripheral: CBPeripheral) {
    guard peripheral.isConnected else { return }
    if #available(iOS 27.0, *) {
        // Cancel the channel sounding session
        peripheral.cancelChannelSoundingSession(config)
    }
}

func peripheral(_ peripheral: CBPeripheral,
                didCompleteChannelSoundingSession error: Error?) {   
    // Session is complete
}

4:41 - Start a Nearby Interaction Channel Sounding session

import CoreBluetooth
import NearbyInteraction

// Configure a Nearby Interaction Channel Sounding session
func startChannelSoundingThroughNearbyInteraction(_ peripheral: CBPeripheral) {
    if #available(iOS 27.0, *) {        
        // Step 1: Check current device supports Bluetooth Channel Sounding
        guard NISession.deviceCapabilities.supportsBluetoothChannelSounding else { return }

        // Step 2: Create an NINearbyAccessoryConfiguration
        let config = NINearbyAccessoryConfiguration(
            bluetoothChannelSoundingIdentifier: peripheral.identifier, 
            previousChannelSoundingIdentifier: nil)

        // Step 3: Enable camera assistance for direction support
        if NISession.deviceCapabilities.supportsCameraAssistance { 
            config.isCameraAssistanceEnabled = true
        }
    }
}

5:19 - Run a Nearby Interaction Channel Sounding session

import CoreBluetooth
import NearbyInteraction

// Run a Nearby Interaction Channel Sounding session
func runChannelSoundingThroughNearbyInteraction(_ config: NINearbyAccessoryConfiguration) {
    // Create an NISession
    let session = NISession()
    session.delegate = self
    // Run the NISession with the accessory configuration
    session.run(config)
}

// Improve Nearby Interaction direction outputs
func updateAccessoryMotionState(_ isMoving: Bool) {
    NIMotionActivityState motionState = isMoving ? .moving : .stationary
    
    // Tell NISession about.the accessory's motion state
    session.updateMotionState(motionState, forObjectWithToken: object.discoveryToken)
}

// Receive NISession updates
func session(_ session: NISession, didUpdate nearbyObjects: [NINearbyObjects]) {   
    guard let object = nearbyObjects.first else { return }

    if let distance = object.distance {
        // Do something with distance
    }

    if let direction = object.horizontalAngle {
        // Do something with horizontal angle
    }
}