鸿蒙智能门铃低功耗解决方案

一、系统架构设计

基于HarmonyOS的分布式能力和低功耗特性，我们设计了一套智能门铃系统，主要功能包括：

1. ​​人体检测优化​​：低功耗AI算法实现高效人体检测
2. ​​智能图像传输​​：动态压缩比选择平衡画质与功耗
3. ​​深度休眠机制​​：超低功耗待机模式延长电池寿命
4. ​​跨设备联动​​：多终端实时接收门铃通知
5. ​​本地边缘计算​​：减少云端依赖降低通信功耗

https://example.com/harmony-smart-doorbell-arch.png

二、核心代码实现

1. 人体检测服务

// MotionDetectionService.ets
import sensor from '@ohos.sensor';
import neuralNetwork from '@ohos.ai.neuralNetwork';
import power from '@ohos.power';

class MotionDetectionService {
  private static instance: MotionDetectionService;
  private model: neuralNetwork.Model | null = null;
  private isActive: boolean = false;
  private powerMode: power.Mode = power.Mode.NORMAL;
  private lastDetectionTime: number = 0;
  
  private constructor() {
    this.initModel();
    this.initPowerListener();
  }

  private async initModel(): Promise<void> {
    try {
      // 加载轻量级人体检测模型
      this.model = await neuralNetwork.loadModel({
        modelPath: 'models/person_detection_lightweight.nn',
        quantization: true // 使用量化模型减少计算量
      });
    } catch (error) {
      console.error('Failed to load model:', error);
    }
  }

  private initPowerListener(): void {
    power.on('powerModeChange', (mode) => {
      this.powerMode = mode;
      this.adjustDetectionParams();
    });
  }

  private adjustDetectionParams(): void {
    if (this.powerMode === power.Mode.POWER_SAVE) {
      // 省电模式下降低检测频率
      sensor.off(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER);
      sensor.on(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, 
        (data) => this.handleMotionData(data), 
        { interval: 2000 } // 2秒采样一次
      );
    } else {
      // 正常模式恢复默认频率
      sensor.off(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER);
      sensor.on(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, 
        (data) => this.handleMotionData(data), 
        { interval: 500 } // 0.5秒采样一次
      );
    }
  }

  private handleMotionData(data: sensor.AccelerometerResponse): void {
    if (!this.isActive || !this.model) return;
    
    // 简单的运动检测
    const motionLevel = Math.abs(data.x) + Math.abs(data.y) + Math.abs(data.z);
    if (motionLevel > 1.5 && Date.now() - this.lastDetectionTime > 1000) {
      this.detectPerson();
    }
  }

  private async detectPerson(): Promise<void> {
    if (!this.model) return;
    
    try {
      const cameraImage = await cameraService.captureLowResImage();
      const input: neuralNetwork.Tensor = {
        data: cameraImage,
        shape: [1, 96, 96, 3] // 低分辨率输入
      };
      
      const output = await this.model.run(input);
      if (output[0][0] > 0.8) { // 检测到人体
        this.lastDetectionTime = Date.now();
        eventService.triggerPersonDetected();
      }
    } catch (error) {
      console.error('Detection failed:', error);
    }
  }

  public static getInstance(): MotionDetectionService {
    if (!MotionDetectionService.instance) {
      MotionDetectionService.instance = new MotionDetectionService();
    }
    return MotionDetectionService.instance;
  }

  public enableDetection(): void {
    this.isActive = true;
    sensor.on(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER, 
      (data) => this.handleMotionData(data), 
      { interval: this.powerMode === power.Mode.POWER_SAVE ? 2000 : 500 }
    );
  }

  public disableDetection(): void {
    this.isActive = false;
    sensor.off(sensor.SensorType.SENSOR_TYPE_ID_ACCELEROMETER);
  }

  public isPersonDetected(): boolean {
    return Date.now() - this.lastDetectionTime < 3000; // 3秒内检测到人
  }
}

export const motionDetection = MotionDetectionService.getInstance();

2. 图像传输服务

// ImageTransferService.ets
import image from '@ohos.multimedia.image';
import buffer from '@ohos.buffer';

class ImageTransferService {
  private static instance: ImageTransferService;
  private qualityLevel: number = 70; // 默认质量
  private powerMode: power.Mode = power.Mode.NORMAL;
  
  private constructor() {
    this.initPowerListener();
  }

  private initPowerListener(): void {
    power.on('powerModeChange', (mode) => {
      this.powerMode = mode;
      this.adjustQualityLevel();
    });
  }

  private adjustQualityLevel(): void {
    switch (this.powerMode) {
      case power.Mode.POWER_SAVE:
        this.qualityLevel = 40; // 低质量
        break;
      case power.Mode.PERFORMANCE:
        this.qualityLevel = 90; // 高质量
        break;
      default:
        this.qualityLevel = 70; // 中等质量
    }
  }

  public static getInstance(): ImageTransferService {
    if (!ImageTransferService.instance) {
      ImageTransferService.instance = new ImageTransferService();
    }
    return ImageTransferService.instance;
  }

  public async compressImage(imageData: image.PixelMap): Promise<ArrayBuffer> {
    const options: image.ImageEncodeOptions = {
      format: 'image/jpeg',
      quality: this.qualityLevel,
      size: this.getTargetSize()
    };
    
    const packedData = await image.packToBuffer(imageData, options);
    return packedData.buffer;
  }

  private getTargetSize(): { width: number, height: number } {
    switch (this.powerMode) {
      case power.Mode.POWER_SAVE:
        return { width: 320, height: 240 }; // 低分辨率
      case power.Mode.PERFORMANCE:
        return { width: 1280, height: 720 }; // 高清
      default:
        return { width: 640, height: 480 }; // 标清
    }
  }

  public async progressiveEncode(imageData: image.PixelMap): Promise<ArrayBuffer[]> {
    // 渐进式编码，先传低质量预览
    const chunks: ArrayBuffer[] = [];
    
    // 第一层：低质量预览
    const preview = await image.packToBuffer(imageData, {
      format: 'image/jpeg',
      quality: 20,
      size: { width: 160, height: 120 }
    });
    chunks.push(preview.buffer);
    
    // 第二层：中等质量
    if (this.qualityLevel > 40) {
      const mid = await image.packToBuffer(imageData, {
        format: 'image/jpeg',
        quality: 60,
        size: { width: 320, height: 240 }
      });
      chunks.push(mid.buffer);
    }
    
    // 第三层：高质量
    if (this.qualityLevel > 70) {
      const high = await image.packToBuffer(imageData, {
        format: 'image/jpeg',
        quality: this.qualityLevel,
        size: this.getTargetSize()
      });
      chunks.push(high.buffer);
    }
    
    return chunks;
  }

  public setCustomQuality(quality: number): void {
    this.qualityLevel = Math.min(100, Math.max(10, quality));
  }
}

export const imageTransfer = ImageTransferService.getInstance();

3. 深度休眠服务

// DeepSleepService.ets
import power from '@ohos.power';
import worker from '@ohos.worker';

class DeepSleepService {
  private static instance: DeepSleepService;
  private sleepWorker: worker.ThreadWorker | null = null;
  private wakeupTimer: number | null = null;
  private isSleeping: boolean = false;
  
  private constructor() {
    this.initWorker();
  }

  private initWorker(): void {
    this.sleepWorker = new worker.ThreadWorker('workers/sleepWorker.js');
    
    this.sleepWorker.onmessage = (event) => {
      this.handleWorkerMessage(event);
    };
    
    this.sleepWorker.onerror = (error) => {
      console.error('Sleep worker error:', error);
    };
  }

  public static getInstance(): DeepSleepService {
    if (!DeepSleepService.instance) {
      DeepSleepService.instance = new DeepSleepService();
    }
    return DeepSleepService.instance;
  }

  public enterDeepSleep(duration: number = 30000): void {
    if (this.isSleeping) return;
    
    this.isSleeping = true;
    
    // 关闭非必要服务
    motionDetection.disableDetection();
    cameraService.turnOff();
    
    // 设置唤醒定时器
    this.wakeupTimer = setTimeout(() => {
      this.wakeUp();
    }, duration);
    
    // 通知Worker进入低功耗模式
    this.sleepWorker?.postMessage({
      command: 'enterDeepSleep',
      duration
    });
    
    // 设置系统低功耗模式
    power.setMode(power.Mode.POWER_SAVE);
  }

  public wakeUp(): void {
    if (!this.isSleeping) return;
    
    if (this.wakeupTimer) {
      clearTimeout(this.wakeupTimer);
      this.wakeupTimer = null;
    }
    
    this.isSleeping = false;
    
    // 恢复服务
    power.setMode(power.Mode.NORMAL);
    cameraService.turnOn();
    motionDetection.enableDetection();
    
    // 通知Worker退出低功耗模式
    this.sleepWorker?.postMessage({
      command: 'wakeUp'
    });
  }

  private handleWorkerMessage(event: MessageEvent): void {
    if (event.data.command === 'wakeupCheck') {
      // 检查是否需要唤醒
      if (motionDetection.isPersonDetected()) {
        this.wakeUp();
      }
    }
  }

  public isInDeepSleep(): boolean {
    return this.isSleeping;
  }

  public setWakeupInterval(interval: number): void {
    this.sleepWorker?.postMessage({
      command: 'setInterval',
      interval
    });
  }
}

export const deepSleep = DeepSleepService.getInstance();

4. 跨设备通知服务

// NotificationService.ets
import distributedData from '@ohos.data.distributedData';
import deviceManager from '@ohos.distributedHardware.deviceManager';
import image from '@ohos.multimedia.image';

class NotificationService {
  private static instance: NotificationService;
  private kvManager: distributedData.KVManager;
  private kvStore: distributedData.KVStore;
  private connectedDevices: string[] = [];
  
  private constructor() {
    this.initKVStore();
    this.initDeviceListener();
  }

  private async initKVStore(): Promise<void> {
    const config = {
      bundleName: 'com.example.smartdoorbell',
      userInfo: { userId: 'default' }
    };
    
    this.kvManager = distributedData.createKVManager(config);
    this.kvStore = await this.kvManager.getKVStore('doorbell_notifications', {
      createIfMissing: true,
      backup: false,
      autoSync: true,
      kvStoreType: distributedData.KVStoreType.SINGLE_VERSION
    });
    
    this.kvStore.on('dataChange', (data) => {
      this.handleRemoteNotifications(data);
    });
  }

  private initDeviceListener(): void {
    deviceManager.on('deviceStateChange', (data) => {
      this.handleDeviceStateChange(data);
    });
    
    this.updateConnectedDevices();
  }

  private async updateConnectedDevices(): Promise<void> {
    const devices = await deviceManager.getTrustedDeviceList();
    this.connectedDevices = devices.map(d => d.deviceId);
  }

  private handleDeviceStateChange(data: deviceManager.DeviceStateChangeData): void {
    if (data.deviceState === deviceManager.DeviceState.ONLINE) {
      if (!this.connectedDevices.includes(data.deviceId)) {
        this.connectedDevices.push(data.deviceId);
      }
    } else if (data.deviceState === deviceManager.DeviceState.OFFLINE) {
      this.connectedDevices = this.connectedDevices.filter(id => id !== data.deviceId);
    }
  }

  public static getInstance(): NotificationService {
    if (!NotificationService.instance) {
      NotificationService.instance = new NotificationService();
    }
    return NotificationService.instance;
  }

  public async sendDoorbellNotification(imageData: image.PixelMap): Promise<void> {
    // 压缩图像
    const compressed = await imageTransfer.compressImage(imageData);
    
    const notification: DoorbellNotification = {
      id: generateId(),
      timestamp: Date.now(),
      imageData: compressed,
      deviceId: deviceManager.getLocalDevice().id
    };
    
    await this.kvStore.put(`notification_${notification.id}`, JSON.stringify(notification));
  }

  public async sendPreviewNotification(imageData: image.PixelMap): Promise<void> {
    // 渐进式编码发送预览
    const chunks = await imageTransfer.progressiveEncode(imageData);
    
    for (const chunk of chunks) {
      const preview: NotificationPreview = {
        id: generateId(),
        timestamp: Date.now(),
        chunk,
        isFinal: chunk === chunks[chunks.length - 1],
        deviceId: deviceManager.getLocalDevice().id
      };
      
      await this.kvStore.put(`preview_${preview.id}`, JSON.stringify(preview));
    }
  }

  private async handleRemoteNotifications(data: distributedData.ChangeInfo): Promise<void> {
    if (data.deviceId === deviceManager.getLocalDevice().id) return;
    
    try {
      const notification = JSON.parse(data.value);
      
      if (data.key.startsWith('notification_')) {
        EventBus.emit('doorbellNotification', notification);
      } else if (data.key.startsWith('preview_')) {
        EventBus.emit('previewUpdate', notification);
      }
    } catch (error) {
      console.error('Failed to parse notification:', error);
    }
  }

  public async getConnectedDevices(): Promise<string[]> {
    await this.updateConnectedDevices();
    return [...this.connectedDevices];
  }

  public async broadcastCommand(command: DoorbellCommand): Promise<void> {
    const cmd: SyncCommand = {
      type: 'command',
      command,
      timestamp: Date.now(),
      deviceId: deviceManager.getLocalDevice().id
    };
    
    await this.kvStore.put(`command_${Date.now()}`, JSON.stringify(cmd));
  }
}

export const notificationService = NotificationService.getInstance();

三、主界面实现

1. 门铃主界面

// DoorbellMainView.ets
@Component
struct DoorbellMainView {
  @State previewImage: Resource = $r('app.media.default_preview');
  @State isActive: boolean = true;
  @State batteryLevel: number = 100;
  @State connectedDevices: number = 0;
  @State notifications: DoorbellNotification[] = [];
  
  aboutToAppear() {
    this.loadInitialState();
    EventBus.on('previewUpdate', (preview) => this.updatePreview(preview));
    EventBus.on('doorbellNotification', (notification) => this.addNotification(notification));
  }

  build() {
    Column() {
      // 状态栏
      Row() {
        Text(`电量: ${this.batteryLevel}%`)
          .fontSize(14)
          .layoutWeight(1)
        
        Text(`设备: ${this.connectedDevices}`)
          .fontSize(14)
          .margin({ right: 16 })
      }
      .margin({ top: 16, bottom: 8 })
      
      // 实时预览
      Image(this.previewImage)
        .width('100%')
        .height(240)
        .objectFit(ImageFit.Cover)
        .margin({ bottom: 16 })
      
      // 控制按钮
      Row() {
        Button(this.isActive ? '禁用' : '启用')
          .onClick(() => this.toggleActiveState())
          .width(120)
        
        Button('设置')
          .onClick(() => this.openSettings())
          .width(120)
          .margin({ left: 16 })
      }
      .margin({ bottom: 24 })
      
      // 通知列表
      Text('最近通知')
        .fontSize(18)
        .fontWeight(FontWeight.Bold)
        .margin({ bottom: 8 })
      
      NotificationList({ notifications: this.notifications })
    }
    .padding(16)
  }

  private async loadInitialState(): Promise<void> {
    this.batteryLevel = power.getBatteryLevel();
    this.connectedDevices = (await notificationService.getConnectedDevices()).length;
    this.isActive = !deepSleep.isInDeepSleep();
  }

  private updatePreview(preview: NotificationPreview): void {
    // 更新预览图像
    this.previewImage = preview.chunk;
    
    // 如果是最终预览，保存到通知列表
    if (preview.isFinal) {
      this.addNotification({
        id: preview.id,
        timestamp: preview.timestamp,
        imageData: preview.chunk,
        deviceId: preview.deviceId
      });
    }
  }

  private addNotification(notification: DoorbellNotification): void {
    this.notifications = [notification, ...this.notifications].slice(0, 10); // 保留最近10条
  }

  private toggleActiveState(): void {
    this.isActive = !this.isActive;
    if (this.isActive) {
      deepSleep.wakeUp();
    } else {
      deepSleep.enterDeepSleep();
    }
  }

  private openSettings(): void {
    router.push({ url: 'pages/Settings' });
  }
}

@Component
struct NotificationList {
  private notifications: DoorbellNotification[];
  
  build() {
    Column() {
      ForEach(this.notifications, (notification) => {
        NotificationItem({ notification })
          .margin({ bottom: 8 })
      })
    }
  }
}

@Component
struct NotificationItem {
  private notification: DoorbellNotification;
  
  build() {
    Row() {
      Image(this.notification.imageData)
        .width(60)
        .height(60)
        .objectFit(ImageFit.Cover)
        .margin({ right: 8 })
      
      Column() {
        Text(this.formatTime(this.notification.timestamp))
          .fontSize(14)
          .fontWeight(FontWeight.Bold)
        
        Text(`来自设备: ${this.notification.deviceId.substr(0, 8)}`)
          .fontSize(12)
          .fontColor('#666666')
      }
      .layoutWeight(1)
      
      Button('查看')
        .width(60)
        .height(30)
    }
    .padding(8)
    .backgroundColor('#FFFFFF')
    .borderRadius(4)
  }

  private formatTime(timestamp: number): string {
    const date = new Date(timestamp);
    return `${date.getHours().toString().padStart(2, '0')}:${date.getMinutes().toString().padStart(2, '0')}`;
  }
}

2. 设置界面

// SettingsView.ets
@Component
struct SettingsView {
  @State motionSensitivity: number = 3;
  @State imageQuality: number = 70;
  @State sleepDelay: number = 30;
  @State powerMode: string = 'normal';
  
  build() {
    Column() {
      // 运动检测灵敏度
      Text('运动检测灵敏度')
        .fontSize(16)
        .margin({ top: 16, bottom: 8 })
      
      Slider({
        value: this.motionSensitivity,
        min: 1,
        max: 5,
        step: 1
      })
      .onChange((value: number) => {
        this.updateMotionSensitivity(value);
      })
      .blockColor('#4A90E2')
      .width('90%')
      .margin({ bottom: 24 })
      
      // 图像质量
      Text(`图像质量: ${this.imageQuality}%`)
        .fontSize(16)
        .margin({ bottom: 8 })
      
      Slider({
        value: this.imageQuality,
        min: 10,
        max: 95,
        step: 5
      })
      .onChange((value: number) => {
        this.updateImageQuality(value);
      })
      .blockColor('#4A90E2')
      .width('90%')
      .margin({ bottom: 24 })
      
      // 休眠延迟
      Text(`无活动时休眠延迟: ${this.sleepDelay}秒`)
        .fontSize(16)
        .margin({ bottom: 8 })
      
      Slider({
        value: this.sleepDelay,
        min: 10,
        max: 120,
        step: 10
      })
      .onChange((value: number) => {
        this.updateSleepDelay(value);
      })
      .blockColor('#4A90E2')
      .width('90%')
      .margin({ bottom: 24 })
      
      // 电源模式
      Text('电源模式')
        .fontSize(16)
        .margin({ bottom: 8 })
      
      RadioGroup({ initial: this.powerMode })
        .onChange((value: string) => {
          this.changePowerMode(value);
        })
        .margin({ bottom: 24 })
      {
        Radio({ value: 'power_save' }).text('省电模式')
        Radio({ value: 'normal' }).text('普通模式')
        Radio({ value: 'performance' }).text('高性能模式')
      }
      
      // 设备管理
      Text('连接设备')
        .fontSize(16)
        .fontWeight(FontWeight.Bold)
        .margin({ bottom: 8 })
      
      DeviceManagement()
        .margin({ bottom: 16 })
    }
    .padding(16)
  }

  private updateMotionSensitivity(value: number): void {
    this.motionSensitivity = value;
    motionDetection.setSensitivity(value);
  }

  private updateImageQuality(value: number): void {
    this.imageQuality = value;
    imageTransfer.setCustomQuality(value);
  }

  private updateSleepDelay(value: number): void {
    this.sleepDelay = value;
    deepSleep.setWakeupInterval(value * 1000);
  }

  private changePowerMode(mode: string): void {
    this.powerMode = mode;
    powerOptimization.setPowerMode(mode);
  }
}

@Component
struct DeviceManagement {
  @State devices: DeviceInfo[] = [];
  
  aboutToAppear() {
    this.loadDevices();
  }

  build() {
    Column() {
      ForEach(this.devices, (device) => {
        DeviceItem({ device })
          .margin({ bottom: 8 })
      })
    }
  }

  private async loadDevices(): Promise<void> {
    const deviceIds = await notificationService.getConnectedDevices();
    this.devices = deviceIds.map(id => ({ id, name: `设备 ${id.substr(0, 8)}` }));
  }
}

@Component
struct DeviceItem {
  private device: DeviceInfo;
  
  build() {
    Row() {
      Text(this.device.name)
        .fontSize(14)
        .layoutWeight(1)
      
      Button('断开')
        .width(60)
        .height(30)
    }
    .padding(8)
    .backgroundColor('#FFFFFF')
    .borderRadius(4)
  }
}

四、高级功能实现

1. 事件处理服务

// EventService.ets
import { motionDetection } from './MotionDetectionService';
import { cameraService } from './CameraService';
import { notificationService } from './NotificationService';

class EventService {
  private static instance: EventService;
  private eventQueue: DoorbellEvent[] = [];
  private isProcessing: boolean = false;
  
  private constructor() {
    this.initEventListeners();
  }

  private initEventListeners(): void {
    motionDetection.onPersonDetected(() => {
      this.handlePersonDetected();
    });
    
    // 其他事件监听...
  }

  public static getInstance(): EventService {
    if (!EventService.instance) {
      EventService.instance = new EventService();
    }
    return EventService.instance;
  }

  private async handlePersonDetected(): Promise<void> {
    // 确保门铃不在休眠状态
    if (deepSleep.isInDeepSleep()) {
      deepSleep.wakeUp();
      await sleep(1000); // 等待设备唤醒
    }
    
    // 捕获图像
    const image = await cameraService.captureImage();
    
    // 添加到事件队列
    this.eventQueue.push({
      type: 'personDetected',
      timestamp: Date.now(),
      imageData: image
    });
    
    // 处理队列
    this.processQueue();
  }

  private async processQueue(): Promise<void> {
    if (this.isProcessing || this.eventQueue.length === 0) return;
    
    this.isProcessing = true;
    const event = this.eventQueue.shift()!;
    
    try {
      // 发送通知到所有设备
      await notificationService.sendPreviewNotification(event.imageData);
      await notificationService.sendDoorbellNotification(event.imageData);
      
      // 保存到本地存储
      await storageService.saveEvent(event);
    } catch (error) {
      console.error('Failed to process event:', error);
      // 重新加入队列
      this.eventQueue.unshift(event);
    } finally {
      this.isProcessing = false;
      
      // 处理下一个事件
      if (this.eventQueue.length > 0) {
        setTimeout(() => this.processQueue(), 500);
      }
    }
  }

  public triggerPersonDetected(): void {
    this.handlePersonDetected();
  }

  public async getRecentEvents(count: number = 10): Promise<DoorbellEvent[]> {
    return this.eventQueue.slice(0, count);
  }
}

export const eventService = EventService.getInstance();

2. 电源优化服务

// PowerOptimizationService.ets
import power from '@ohos.power';
import { motionDetection } from './MotionDetectionService';
import { cameraService } from './CameraService';
import { imageTransfer } from './ImageTransferService';

class PowerOptimizationService {
  private static instance: PowerOptimizationService;
  private currentMode: power.Mode = power.Mode.NORMAL;
  
  private constructor() {
    this.initPowerListener();
  }

  private initPowerListener(): void {
    power.on('powerModeChange', (mode) => {
      this.handlePowerModeChange(mode);
    });
  }

  public static getInstance(): PowerOptimizationService {
    if (!PowerOptimizationService.instance) {
      PowerOptimizationService.instance = new PowerOptimizationService();
    }
    return PowerOptimizationService.instance;
  }

  public setPowerMode(mode: string): void {
    let powerMode: power.Mode;
    switch (mode) {
      case 'power_save': powerMode = power.Mode.POWER_SAVE; break;
      case 'performance': powerMode = power.Mode.PERFORMANCE; break;
      default: powerMode = power.Mode.NORMAL;
    }
    
    power.setMode(powerMode);
  }

  private handlePowerModeChange(mode: power.Mode): void {
    this.currentMode = mode;
    
    // 调整各服务参数
    switch (mode) {
      case power.Mode.POWER_SAVE:
        this.enablePowerSaveMode();
        break;
      case power.Mode.PERFORMANCE:
        this.enablePerformanceMode();
        break;
      default:
        this.enableNormalMode();
    }
  }

  private enablePowerSaveMode(): void {
    // 降低运动检测灵敏度
    motionDetection.setSensitivity(2);
    
    // 降低图像质量
    imageTransfer.setCustomQuality(40);
    
    // 减少相机帧率
    cameraService.setFrameRate(5);
    
    // 更快的休眠
    deepSleep.setWakeupInterval(10000); // 10秒
  }

  private enablePerformanceMode(): void {
    // 提高运动检测灵敏度
    motionDetection.setSensitivity(4);
    
    // 提高图像质量
    imageTransfer.setCustomQuality(90);
    
    // 提高相机帧率
    cameraService.setFrameRate(30);
    
    // 禁用自动休眠
    deepSleep.setWakeupInterval(0);
  }

  private enableNormalMode(): void {
    // 恢复默认设置
    motionDetection.setSensitivity(3);
    imageTransfer.setCustomQuality(70);
    cameraService.setFrameRate(15);
    deepSleep.setWakeupInterval(30000); // 30秒
  }

  public getCurrentMode(): power.Mode {
    return this.currentMode;
  }
}

export const powerOptimization = PowerOptimizationService.getInstance();

3. 相机服务

// CameraService.ets
import camera from '@ohos.multimedia.camera';
import image from '@ohos.multimedia.image';
import power from '@ohos.power';

class CameraService {
  private static instance: CameraService;
  private cameraDevice: camera.CameraDevice | null = null;
  private isOn: boolean = false;
  private frameRate: number = 15;
  private powerMode: power.Mode = power.Mode.NORMAL;
  
  private constructor() {
    this.initPowerListener();
  }

  private initPowerListener(): void {
    power.on('powerModeChange', (mode) => {
      this.powerMode = mode;
      this.adjustCameraParams();
    });
  }

  public static getInstance(): CameraService {
    if (!CameraService.instance) {
      CameraService.instance = new CameraService();
    }
    return CameraService.instance;
  }

  public async turnOn(): Promise<void> {
    if (this.isOn) return;
    
    try {
      this.cameraDevice = await camera.getCameraDevice(camera.LensType.BACK);
      await this.cameraDevice.setFrameRate(this.getTargetFrameRate());
      this.isOn = true;
    } catch (error) {
      console.error('Failed to turn on camera:', error);
    }
  }

  public async turnOff(): Promise<void> {
    if (!this.isOn || !this.cameraDevice) return;
    
    try {
      await this.cameraDevice.release();
      this.cameraDevice = null;
      this.isOn = false;
    } catch (error) {
      console.error('Failed to turn off camera:', error);
    }
  }

  public async captureImage(): Promise<image.PixelMap> {
    if (!this.isOn || !this.cameraDevice) {
      throw new Error('Camera is not ready');
    }
    
    return await this.cameraDevice.capture();
  }

  public async captureLowResImage(): Promise<image.PixelMap> {
    if (!this.isOn || !this.cameraDevice) {
      throw new Error('Camera is not ready');
    }
    
    return await this.cameraDevice.capture({
      quality: 'low' // 低分辨率捕获
    });
  }

  public setFrameRate(rate: number): void {
    this.frameRate = rate;
    if (this.isOn && this.cameraDevice) {
      this.cameraDevice.setFrameRate(this.getTargetFrameRate());
    }
  }

  private getTargetFrameRate(): number {
    switch (this.powerMode) {
      case power.Mode.POWER_SAVE: return 5;
      case power.Mode.PERFORMANCE: return 30;
      default: return this.frameRate;
    }
  }

  private adjustCameraParams(): void {
    if (!this.isOn) return;
    
    if (this.cameraDevice) {
      this.cameraDevice.setFrameRate(this.getTargetFrameRate());
    }
  }

  public isCameraOn(): boolean {
    return this.isOn;
  }
}

export const cameraService = CameraService.getInstance();

五、总结

本智能门铃低功耗方案实现了以下核心价值：

1. ​​高效人体检测​​：量化AI模型结合运动传感器降低计算功耗
2. ​​智能图像传输​​：动态压缩比和渐进式编码优化网络传输
3. ​​深度休眠技术​​：待机电流低至微安级大幅延长电池寿命
4. ​​跨设备协同​​：多终端实时接收门铃通知和视频流
5. ​​自适应电源管理​​：根据场景动态调整性能与功耗平衡

​​扩展方向​​：

1. 增加人脸识别功能
2. 开发本地语音对讲功能
3. 添加太阳能充电支持
4. 集成到智能家居安防系统
5. 支持更多通信协议如Zigbee/LoRa

注意事项：
1. 需要申请ohos.permission.CAMERA权限
2. 人体检测模型需根据实际场景优化
3. 深度休眠期间无法响应门铃按键
4. 图像质量设置会影响电池续航
5. 首次使用建议进行灵敏度校准