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 的目标并不是在抛光度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，以及 Python >= 3.10。由于此项目的代码完全 开源，你可以随时提交合并请求，或者分叉项目以探索全新的方向。
你将需要：
- 获取 COLMI R02 实际设备，价格在撰写时为 11 到 30 美金左右。
- 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。
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。
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 = false var 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 in if 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 = nil manager = 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 = knownPeripheral peripheral?.delegate = self connect() } 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 = self print("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 = false characteristicsDiscovered = 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 = characteristic case CBUUID(string: Self.uartTxCharacteristicUUID): print("DEBUG: Found UART TX characteristic") self.uartTxCharacteristic = characteristic peripheral.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 = false var pickerDismissed = true var 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 = false override init() { super.init() self.session.activate(on: DispatchQueue.main, eventHandler: handleSessionEvent(event:)) } // MARK: - RingSessionManager actions func presentPicker() { session.showPicker(for: [Self.ring]) { error in if let error { print("Failed to show picker due to: (error.localizedDescription)") } } } func removeRing() { guard let currentRing else { return } if peripheralConnected { disconnect() } session.removeAccessory(currentRing) { _ in self.currentRing = nil self.manager = nil } } 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) } func disconnect() { guard let peripheral, let manager else { return } manager.cancelPeripheralConnection(peripheral) } // MARK: - ASAccessorySession functions private func saveRing(ring: ASAccessory) { currentRing = ring if 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 = nil self.manager = nil case .pickerDidPresent: pickerDismissed = false case .pickerDidDismiss: pickerDismissed = true default: 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 = knownPeripheral peripheral?.delegate = self connect() } 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 = self print("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 = false characteristicsDiscovered = 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 = characteristic case CBUUID(string: Self.uartTxCharacteristicUUID): print("DEBUG: Found UART TX characteristic") self.uartTxCharacteristic = characteristic peripheral.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 AccessorySetupKit struct 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) } @ViewBuilder private 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
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