在飞速发展的可穿戴技术领域，我们正处于一个十字路口——市场上充斥着各式时尚、功能丰富的设备，声称能够彻底改变我们对健康和健身的方式。
然而，在这些光鲜的外观和营销宣传背后，隐藏着一个令人担忧的现实：大多数这些设备是封闭系统，其内部运行被专有代码和封闭硬件所掩盖。作为消费者，我们对这些设备如何收集、处理及可能共享我们的健康数据一无所知。
这时，Halo 出现了，它是一种旨在让健康追踪更加普惠化的开源替代方案。通过这系列文章，我们将引导你从基础入手，构建并使用完全透明、可定制的可穿戴设备。
需要说明的是，Halo 的目标并不是在外观或功能完整性上与消费级可穿戴设备竞争。相反，它提供了一种独特的、动手实践的方式来理解健康追踪设备背后的技术。
我们将使用 Swift 5 来构建对应的 iOS 界面，Python >= 3.10。由于此项目的代码完全开源，你可以随时提交 PR 拉取请求，或者 Fork 分叉项目以探索全新的方向。
开源https://github.com/cyrilzakka/Halo-iOS
你将需要：
获取COLMI R02实体设备，价格在撰写时为 11 到 30 美金左右。https://www.aliexpress.us/item/3256806445134241.html?gatewayAdapt=glo2usa4itemAdapt
一个安装了 Xcode 16 的开发环境，以及可选的 Apple 开发者计划会员资格。
Python >= 3.10，并安装了pandas、numpy、torch当然还有transformers。
致谢
此项目基于Python 仓库的代码及我的学习成果构建。
Python 仓库https://tahnok.github.io/colmi_r02_client/
免责声明
作为一名医生，我有法律义务提醒你：你即将阅读的内容并不是医学建议。现在，让我们开始让一些可穿戴设备发出蜂鸣声吧！
配对戒指
在进入代码之前，让我们先了解蓝牙低能耗 (BLE) 的关键规格。BLE 基于一个简单的客户端-服务器模型，使用三个核心概念：中央设备 (Centrals) 、服务 (Services) 和 **特征 (Characteristics)**。以下是它们的具体介绍：
中央设备 (例如你的 iPhone) 负责启动和管理与外设 (例如我们的 COLMI R02 戒指) 的连接。戒指通过广播自身信息等待手机连接，每次仅支持一台手机连接。
服务 是戒指上相关功能的集合，例如心率监测服务或电池状态服务。每个服务都有一个唯一标识符 (UUID) ，客户端通过它来找到对应服务。
特征 是每个服务中的具体数据点或控制机制。例如，它们可能是只读 (获取传感器数据) 、只写 (发送命令) 或两者兼有。有些特征还能在其值发生变化时自动通知手机，这对于实时健康监测尤为重要。
当手机连接到戒指时，会定位所需的服务，并与特定特征交互以发送命令或接收数据。这种结构化的方法不仅确保了通信效率，还能延长电池使用时间。了解了这些基础知识后，让我们开始构建吧！
设置 Xcode 项目
创建一个名为 Halo 的新项目，目标平台为 iOS。组织标识符建议使用反向域名格式 (如 com.example) 。本项目中，我们使用 com.FirstNameLastName。
接下来，为应用启用必要的功能。在 Xcode 中，打开 Signing & Capabilities 选项卡，启用以下 后台模式 (Background Modes)，以确保应用在后台运行时能够保持与戒指的连接并处理数据。
然后，我们将使用 Apple 提供的最新框架AccessorySetupKit，用于将蓝牙和 Wi-Fi 配件连接到 iOS 应用。此框架自 iOS 18 推出，替代了传统的广泛蓝牙权限请求方式，专注于为用户明确批准的特定设备提供访问权限。
AccessorySetupKithttps://developer.apple.com/documentation/accessorysetupkit/
当用户尝试将 COLMI R02 戒指连接到应用时，AccessorySetupKit 会显示一个系统界面，仅列出兼容的附近设备。用户选择设备后，应用即可与戒指通信，而无需请求完整的蓝牙权限。这大大提升了用户隐私，同时简化了设备连接的管理流程。
打开 Info.plist 文件 (可以在左侧边栏中找到，或通过 Project Navigator (⌘1) > Your Target > Info 定位) 。添加以下键值条目以支持与 COLMI R02 戒指的配对：
添加
NSAccessorySetupKitSupports，类型为Array，并将Bluetooth作为第一个项目。添加
NSAccessorySetupBluetoothServices，类型为Array，并将以下 UUID 作为String项：6E40FFF0-B5A3-F393-E0A9-E50E24DCCA9E0000180A-0000-1000-8000-00805F9B34FB
至此，初步配置完成！🤗
Ring Session Manager 类
接下来，我们将创建一个 RingSessionManager 类，用于管理所有与戒指的通信。此类的主要职责包括：
扫描附近的戒指
连接到戒指
发现服务和特征
实现数据读写操作
第一步：创建 RingSessionManager
首先创建一个新的 Swift 文件 (⌘N) ，命名为 RingSessionManager.swift。以下是类的定义以及需要实现的关键属性：
@Observable
class RingSessionManager: NSObject {// 追踪连接状态var peripheralConnected = falsevar pickerDismissed = true// 存储当前连接的戒指var currentRing: ASAccessory?private var session = ASAccessorySession()// 核心蓝牙对象private var manager: CBCentralManager?private var peripheral: CBPeripheral?
}第二步：发现戒指
戒指通过特定的蓝牙服务 UUID 进行广播。为了找到它，我们需要创建一个 ASDiscoveryDescriptor 对象，指定其蓝牙服务的 UUID。以下代码完成了这一功能：
private static let ring: ASPickerDisplayItem = {let descriptor = ASDiscoveryDescriptor()descriptor.bluetoothServiceUUID = CBUUID(string: "6E40FFF0-B5A3-F393-E0A9-E50E24DCCA9E")return ASPickerDisplayItem(name: "COLMI R02 Ring",productImage: UIImage(named: "colmi")!,descriptor: descriptor)
}()确保将戒指图片添加到项目资源目录中，或者用合适的占位符替换 UIImage(named: "colmi")!。
第三步：显示戒指选择器
为了让用户选择戒指，我们调用系统内置的设备选择器界面：
func presentPicker() {session.showPicker(for: [Self.ring]) { error inif let error {print("Failed to show picker: \(error.localizedDescription)")}}
}第四步：处理戒指选择
当用户从选择器中选定设备后，应用需要处理连接和管理逻辑。以下代码实现了事件处理：
private func handleSessionEvent(event: ASAccessoryEvent) {switch event.eventType {case .accessoryAdded:guard let ring = event.accessory else { return }saveRing(ring: ring)case .activated:// 重新连接已配对戒指guard let ring = session.accessories.first else { return }saveRing(ring: ring)case .accessoryRemoved:currentRing = nilmanager = nil}
}第五步：建立连接
完成选择戒指后，我们需要与其建立蓝牙连接：
func connect() {guard let manager, manager.state == .poweredOn, let peripheral else { return }let options: [String: Any] = [CBConnectPeripheralOptionNotifyOnConnectionKey: true,CBConnectPeripheralOptionNotifyOnDisconnectionKey: true,CBConnectPeripheralOptionStartDelayKey: 1]manager.connect(peripheral, options: options)
}第六步：理解委托方法
在 RingSessionManager 中，我们实现了两个关键的委托协议，用于管理蓝牙通信过程。
中央管理器委托 (CBCentralManagerDelegate)此委托主要处理蓝牙连接的整体状态。
func centralManagerDidUpdateState(_ central: CBCentralManager) {print("Central manager state: \(central.state)")switch central.state {case .poweredOn:if let peripheralUUID = currentRing?.bluetoothIdentifier {if let knownPeripheral = central.retrievePeripherals(withIdentifiers: [peripheralUUID]).first {print("Found previously connected peripheral")peripheral = knownPeripheralperipheral?.delegate = selfconnect()} else {print("Known peripheral not found, starting scan")}}default:peripheral = nil}
}当蓝牙开启时，程序会检查是否有已连接的戒指，并尝试重新连接。
成功连接后：
func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {print("DEBUG: Connected to peripheral: \(peripheral)")peripheral.delegate = selfprint("DEBUG: Discovering services...")peripheral.discoverServices([CBUUID(string: Self.ringServiceUUID)])peripheralConnected = true
}断开连接时：
func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: (any Error)?) {print("Disconnected from peripheral: \(peripheral)")peripheralConnected = falsecharacteristicsDiscovered = false
}外设委托 (CBPeripheralDelegate)
此委托主要处理与戒指的具体通信。
首先发现戒指的服务：
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: (any Error)?) {print("DEBUG: Services discovery callback, error: \(String(describing: error))")guard error == nil, let services = peripheral.services else {print("DEBUG: No services found or error occurred")return}print("DEBUG: Found \(services.count) services")for service in services {if service.uuid == CBUUID(string: Self.ringServiceUUID) {print("DEBUG: Found ring service, discovering characteristics...")peripheral.discoverCharacteristics([CBUUID(string: Self.uartRxCharacteristicUUID),CBUUID(string: Self.uartTxCharacteristicUUID)], for: service)}}
}发现特征后：
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {print("DEBUG: Characteristics discovery callback, error: \(String(describing: error))")guard error == nil, let characteristics = service.characteristics else {print("DEBUG: No characteristics found or error occurred")return}print("DEBUG: Found \(characteristics.count) characteristics")for characteristic in characteristics {switch characteristic.uuid {case CBUUID(string: Self.uartRxCharacteristicUUID):print("DEBUG: Found UART RX characteristic")self.uartRxCharacteristic = characteristiccase CBUUID(string: Self.uartTxCharacteristicUUID):print("DEBUG: Found UART TX characteristic")self.uartTxCharacteristic = characteristicperipheral.setNotifyValue(true, for: characteristic)default:print("DEBUG: Found other characteristic: \(characteristic.uuid)")}}characteristicsDiscovered = true
}接收数据时：
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {if characteristic.uuid == CBUUID(string: Self.uartTxCharacteristicUUID) {if let value = characteristic.value {print("Received value: \(value)")}}
}发送命令后：
func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {if let error = error {print("Write to characteristic failed: \(error.localizedDescription)")} else {print("Write to characteristic successful")}
}完整代码
完整的 RingSessionManager 类代码如下：
import Foundation
import AccessorySetupKit
import CoreBluetooth
import SwiftUI@Observable
class RingSessionManager: NSObject {var peripheralConnected = falsevar pickerDismissed = truevar currentRing: ASAccessory?private var session = ASAccessorySession()private var manager: CBCentralManager?private var peripheral: CBPeripheral?private var uartRxCharacteristic: CBCharacteristic?private var uartTxCharacteristic: CBCharacteristic?private static let ringServiceUUID = "6E40FFF0-B5A3-F393-E0A9-E50E24DCCA9E"private static let uartRxCharacteristicUUID = "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"private static let uartTxCharacteristicUUID = "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"private static let deviceInfoServiceUUID = "0000180A-0000-1000-8000-00805F9B34FB"private static let deviceHardwareUUID = "00002A27-0000-1000-8000-00805F9B34FB"private static let deviceFirmwareUUID = "00002A26-0000-1000-8000-00805F9B34FB"private static let ring: ASPickerDisplayItem = {let descriptor = ASDiscoveryDescriptor()descriptor.bluetoothServiceUUID = CBUUID(string: ringServiceUUID)return ASPickerDisplayItem(name: "COLMI R02 Ring",productImage: UIImage(named: "colmi")!,descriptor: descriptor)}()private var characteristicsDiscovered = falseoverride init() {super.init()self.session.activate(on: DispatchQueue.main, eventHandler: handleSessionEvent(event:))}// MARK: - RingSessionManager actionsfunc presentPicker() {session.showPicker(for: [Self.ring]) { error inif let error {print("Failed to show picker due to: \(error.localizedDescription)")}}}func removeRing() {guard let currentRing else { return }if peripheralConnected {disconnect()}session.removeAccessory(currentRing) { _ inself.currentRing = nilself.manager = nil}}func connect() {guardlet manager, manager.state == .poweredOn,let peripheralelse {return}let options: [String: Any] = [CBConnectPeripheralOptionNotifyOnConnectionKey: true,CBConnectPeripheralOptionNotifyOnDisconnectionKey: true,CBConnectPeripheralOptionStartDelayKey: 1]manager.connect(peripheral, options: options)}func disconnect() {guard let peripheral, let manager else { return }manager.cancelPeripheralConnection(peripheral)}// MARK: - ASAccessorySession functionsprivate func saveRing(ring: ASAccessory) {currentRing = ringif manager == nil {manager = CBCentralManager(delegate: self, queue: nil)}}private func handleSessionEvent(event: ASAccessoryEvent) {switch event.eventType {case .accessoryAdded, .accessoryChanged:guard let ring = event.accessory else { return }saveRing(ring: ring)case .activated:guard let ring = session.accessories.first else { return }saveRing(ring: ring)case .accessoryRemoved:self.currentRing = nilself.manager = nilcase .pickerDidPresent:pickerDismissed = falsecase .pickerDidDismiss:pickerDismissed = truedefault:print("Received event type \(event.eventType)")}}
}// MARK: - CBCentralManagerDelegate
extension RingSessionManager: CBCentralManagerDelegate {func centralManagerDidUpdateState(_ central: CBCentralManager) {print("Central manager state: \(central.state)")switch central.state {case .poweredOn:if let peripheralUUID = currentRing?.bluetoothIdentifier {if let knownPeripheral = central.retrievePeripherals(withIdentifiers: [peripheralUUID]).first {print("Found previously connected peripheral")peripheral = knownPeripheralperipheral?.delegate = selfconnect()} else {print("Known peripheral not found, starting scan")}}default:peripheral = nil}}func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {print("DEBUG: Connected to peripheral: \(peripheral)")peripheral.delegate = selfprint("DEBUG: Discovering services...")peripheral.discoverServices([CBUUID(string: Self.ringServiceUUID)])peripheralConnected = true}func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: (any Error)?) {print("Disconnected from peripheral: \(peripheral)")peripheralConnected = falsecharacteristicsDiscovered = false}func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: (any Error)?) {print("Failed to connect to peripheral: \(peripheral), error: \(error.debugDescription)")}
}// MARK: - CBPeripheralDelegate
extension RingSessionManager: CBPeripheralDelegate {func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: (any Error)?) {print("DEBUG: Services discovery callback, error: \(String(describing: error))")guard error == nil, let services = peripheral.services else {print("DEBUG: No services found or error occurred")return}print("DEBUG: Found \(services.count) services")for service in services {if service.uuid == CBUUID(string: Self.ringServiceUUID) {print("DEBUG: Found ring service, discovering characteristics...")peripheral.discoverCharacteristics([CBUUID(string: Self.uartRxCharacteristicUUID),CBUUID(string: Self.uartTxCharacteristicUUID)], for: service)}}}func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {print("DEBUG: Characteristics discovery callback, error: \(String(describing: error))")guard error == nil, let characteristics = service.characteristics else {print("DEBUG: No characteristics found or error occurred")return}print("DEBUG: Found \(characteristics.count) characteristics")for characteristic in characteristics {switch characteristic.uuid {case CBUUID(string: Self.uartRxCharacteristicUUID):print("DEBUG: Found UART RX characteristic")self.uartRxCharacteristic = characteristiccase CBUUID(string: Self.uartTxCharacteristicUUID):print("DEBUG: Found UART TX characteristic")self.uartTxCharacteristic = characteristicperipheral.setNotifyValue(true, for: characteristic)default:print("DEBUG: Found other characteristic: \(characteristic.uuid)")}}characteristicsDiscovered = true}func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {if characteristic.uuid == CBUUID(string: Self.uartTxCharacteristicUUID) {if let value = characteristic.value {print("Received value: \(value)")}}}func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {if let error = error {print("Write to characteristic failed: \(error.localizedDescription)")} else {print("Write to characteristic successful")}}
}最后一步：将其应用到我们的应用程序中
在 ContentView.swift 中粘贴以下代码，作为主界面的一部分：
import SwiftUI
import AccessorySetupKitstruct ContentView: View {@State var ringSessionManager = RingSessionManager()var body: some View {List {Section("MY DEVICE", content: {if ringSessionManager.pickerDismissed, let currentRing = ringSessionManager.currentRing {makeRingView(ring: currentRing)} else {Button {ringSessionManager.presentPicker()} label: {Text("Add Ring").frame(maxWidth: .infinity).font(Font.headline.weight(.semibold))}}})}.listStyle(.insetGrouped)}@ViewBuilderprivate func makeRingView(ring: ASAccessory) -> some View {HStack {Image("colmi").resizable().aspectRatio(contentMode: .fit).frame(height: 70)VStack(alignment: .leading) {Text(ring.displayName).font(Font.headline.weight(.semibold))}}}
}#Preview {ContentView()
}如果一切配置正确，你现在可以构建并运行应用。当点击“Add Ring”按钮时，将弹出一个界面，显示附近的兼容设备 (包括 COLMI R02 戒指) 。选择设备后，应用即可完成连接。🎉
在后续的文章中，我们将进一步探索如何与戒指交互，包括读取电池电量、获取传感器数据 (如 PPG 和加速度计) ，并基于这些数据开发实时心率监测、活动追踪及睡眠检测功能。敬请期待！
英文原文:https://hf.co/blog/cyrilzakka/halo-introduction
原文作者: Cyril, ML Researcher, Health AI Lead @ Hugging Face
译者: Lu Cheng, Hugging Face Fellow
