1.前言

微信小程序中连接蓝牙设备，信息写入流程
1、检测当前使用设备（如自己的手机）是否支持蓝牙/蓝牙开启状态
wx:openBluetoothAdapter({})
2、如蓝牙已开启状态，检查蓝牙适配器的状态
wx.getBluetoothAdapterState({})
3、添加监听蓝牙适配器状态变化
wx.onBluetoothAdapterStateChange({})
4、搜索附近蓝牙设备
wx.startBluetoothDevicesDiscovery({})
5、监听搜索的到设备
wx.onBluetoothDeviceFound({})
遍历设备列表找到和macAddr（看自己家的蓝牙装置的物理地址）匹配的设备的deviceId
6、连接想要连接的切匹配成功的设备
wx.createBLEConnection({})
7、获取连接成功的设备的设备服务servicesID
wx.getBLEDeviceServices({})
8、获取设备特征id
wx.getBLEDeviceCharacteristics({})
9、向设备写入指令
wx.writeBLECharacteristicValue({})

以下是代码重点，本人亲测有效，集官网和百家之所长，汇聚之大成，入我门来，使君不负观赏

#2. 小程序前端index.wxml

<wxs module="utils">
module.exports.max = function(n1, n2) {return Math.max(n1, n2)
}
module.exports.len = function(arr) {arr = arr || []return arr.length
}
</wxs>
<button bindtap="openBluetoothAdapter"   class="primary-btn" >开始扫描</button>
<button bindtap="closeBLEConnection"  class="default-btn" >断开连接</button>
<button bindtap="opendeng"   class="sumit-btn" >开灯</button>
<button bindtap="guandeng"   class="warn-btn" >关灯</button><view class="devices_summary">已发现 {{devices.length}} 个外围设备：</view>
<scroll-view class="device_list" scroll-y scroll-with-animation><view wx:for="{{devices}}" wx:key="index"data-device-id="{{item.deviceId}}"data-name="{{item.name || item.localName}}"bindtap="createBLEConnection" class="device_item"hover-class="device_item_hover"><view style="font-size: 16px; color: #333;">{{item.name}}</view><view style="font-size: 10px">信号强度: {{item.RSSI}}dBm ({{utils.max(0, item.RSSI + 100)}}%)</view><view style="font-size: 10px">UUID: {{item.deviceId}}</view><view style="font-size: 10px">Service数量: {{utils.len(item.advertisServiceUUIDs)}}</view></view>
</scroll-view><view class="connected_info" wx:if="{{connected}}"><view><icon class="icon-box-img" type="success" size="33"></icon><view class="icon-box-text"> {{name}}连接成功！！！</view></view> </view>

3.小程序index.wxss

page {color: #333;
}
.icon-box-img{height: 20px;float: left;margin-left: 20%;
}
.icon-box-text{height: 30px;line-height: 30px;margin-left:5px;float: left;
}.primary-btn{margin-top: 30rpx;/* border: rgb(7, 80, 68) 1px solid; */color: rgb(241, 238, 238);background-color: rgb(14, 207, 46);
}
.default-btn{margin-top: 30rpx;/* border: #333 1px solid; */color: rgb(243, 236, 236);background-color: rgb(189, 112, 25);
}.warn-btn{margin-top: 30rpx;/* border: #333 1px solid; */color: rgb(240, 231, 231);background-color: rgb(235, 10, 10);
}
.sumit-btn{margin-top: 30px;width: 60px;color: rgb(240, 231, 231);background-color: rgb(10, 100, 235);
}.devices_summary {margin-top: 30px;padding: 10px;font-size: 16px;
}
.device_list {height: 300px;margin: 50px 5px;margin-top: 0;border: 1px solid #EEE;border-radius: 5px;width: auto;
}
.device_item {border-bottom: 1px solid #EEE;padding: 10px;color: #666;
}
.device_item_hover {background-color: rgba(0, 0, 0, .1);
}
.connected_info {position: fixed;bottom: 10px;width: 80%;margin-left: 6%;background-color: #F0F0F0;padding: 10px;padding-bottom: 20px;margin-bottom: env(safe-area-inset-bottom);font-size: 18px;/* line-height: 20px; */color: #1da54d;text-align: center;/* height: 20px; */box-shadow: 0px 0px 3px 0px;
}
.connected_info .operation {position: absolute;display: inline-block;right: 30px;
}

4.小程序 index.ts

const app = getApp()function inArray(arr, key, val) {for (let i = 0; i < arr.length; i++) {if (arr[i][key] === val) {return i;}}return -1;
}// ArrayBuffer转16进度字符串示例
function ab2hex(buffer) {var hexArr = Array.prototype.map.call(new Uint8Array(buffer),function (bit) {return ('00' + bit.toString(16)).slice(-2)})return hexArr.join('');
}Page({data: {devices: [],connected: false,chs: [],},getCeshi() {wx.navigateTo({url: '/pages/main/main',})},// 搜寻周边蓝牙openBluetoothAdapter() {//console.log('openBluetoothAdapter success')wx.openBluetoothAdapter({success: (res) => {console.log('openBluetoothAdapter success', res)this.startBluetoothDevicesDiscovery()},fail: (res) => {if (res.errCode === 10001) {wx.onBluetoothAdapterStateChange(function (res) {console.log('onBluetoothAdapterStateChange', res)if (res.available) {this.startBluetoothDevicesDiscovery()}})}}})},// 停止搜寻周边蓝牙getBluetoothAdapterState() {wx.getBluetoothAdapterState({success: (res) => {console.log('getBluetoothAdapterState', res)if (res.discovering) {this.onBluetoothDeviceFound()} else if (res.available) {this.startBluetoothDevicesDiscovery()}}})},// 开始搜寻附近的蓝牙外围设备startBluetoothDevicesDiscovery() {if (this._discoveryStarted) {return}this._discoveryStarted = truewx.startBluetoothDevicesDiscovery({allowDuplicatesKey: true,success: (res) => {console.log('startBluetoothDevicesDiscovery success', res)this.onBluetoothDeviceFound()},})},//停止搜寻附近的蓝牙外围设备。若已经找到需要的蓝牙设备并不需要继续搜索时，建议调用该接口停止蓝牙搜索。stopBluetoothDevicesDiscovery() {wx.stopBluetoothDevicesDiscovery()},//监听搜索到新设备的事件onBluetoothDeviceFound() {wx.onBluetoothDeviceFound((res) => {res.devices.forEach(device => {if (!device.name && !device.localName) {return}const foundDevices = this.data.devicesconst idx = inArray(foundDevices, 'deviceId', device.deviceId)const data = {}if (idx === -1) {data[`devices[${foundDevices.length}]`] = device} else {data[`devices[${idx}]`] = device}this.setData(data)})})},//连接蓝牙低功耗设备。createBLEConnection(e) {const ds = e.currentTarget.datasetconst deviceId = ds.deviceIdconst name = ds.namewx.createBLEConnection({deviceId,success: (res) => {this.setData({connected: true,name,deviceId,})this.getBLEDeviceServices(deviceId)}})this.stopBluetoothDevicesDiscovery()},closeBLEConnection() {wx.closeBLEConnection({deviceId: this.data.deviceId})this.setData({connected: false,chs: [],canWrite: false,})},//获取蓝牙低功耗设备所有服务。getBLEDeviceServices(deviceId) {console.log('deviceId ========', deviceId)wx.getBLEDeviceServices({deviceId,success: (res) => {for (let i = 0; i < res.services.length; i++) {//获取通过设备id多个特性服务serviceid （包含 读、写、通知、等特性服务）//   console.log('serviceId ========', res.services[2].uuid)// 通过上边注释解封，排查到判断服务id 中第三个服务id  代表写入服务//  isPrimary代表 ：判断服务id是否为主服务// if (res.services[2].isPrimary) {//  this.getBLEDeviceCharacteristics(deviceId, res.services[2].uuid)//  }//判断通过（设备id获取的多个特性服务）中是否有与（蓝牙助手获取的写入特性服务），相一致的serviceidif (res.services[i].uuid=="0000FFE0-0000-1000-8000-00805F9B34FB") {this.getBLEDeviceCharacteristics(deviceId, res.services[i].uuid) }}}})},//获取蓝牙低功耗设备某个服务中所有特征 (characteristic)。getBLEDeviceCharacteristics(deviceId, serviceId) {console.info("蓝牙的deviceId====" + deviceId);console.info("蓝牙服务的serviceId====" + serviceId);wx.getBLEDeviceCharacteristics({deviceId,serviceId,success: (res) => {console.log('getBLEDeviceCharacteristics success', res.characteristics)for (let i = 0; i < res.characteristics.length; i++) {let item = res.characteristics[i]if (item.properties.read) {wx.readBLECharacteristicValue({deviceId,serviceId,characteristicId: item.uuid,})}if (item.properties.write) {this.setData({canWrite: true})this._deviceId = deviceIdthis._serviceId = serviceIdthis._characteristicId = item.uuidconsole.info("写入（第一步）的characteristicId====" + item.uuid);//初始化调用 写入信息的方法  1：代表开灯this.writeBLECharacteristicValue("1")}if (item.properties.notify || item.properties.indicate) {wx.notifyBLECharacteristicValueChange({deviceId,serviceId,characteristicId: item.uuid,state: true,})}}},fail(res) {console.error('getBLEDeviceCharacteristics', res)}})// 操作之前先监听，保证第一时间获取数据wx.onBLECharacteristicValueChange((characteristic) => {const idx = inArray(this.data.chs, 'uuid', characteristic.characteristicId)const data = {}if (idx === -1) {data[`chs[${this.data.chs.length}]`] = {uuid: characteristic.characteristicId,value: ab2hex(characteristic.value)}} else {data[`chs[${idx}]`] = {uuid: characteristic.characteristicId,value: ab2hex(characteristic.value)}}this.setData(data)})},/*** 写入的数据 格式转换* @param str* @returns 字符串 转 ArrayBuffer*/
hex2buffer(str) {console.info("写入的数据====" + str);//字符串 转 十六进制var val = "";for (var i = 0; i < str.length; i++) {if (val == "")val = str.charCodeAt(i).toString(16);elseval += "," + str.charCodeAt(i).toString(16);}//十六进制 转 ArrayBuffervar buffer = new Uint8Array(val.match(/[\da-f]{2}/gi).map(function (h) {return parseInt(h, 16)})).buffer;return buffer;
},
//开灯
opendeng() {// 调用写入信息的方法 向蓝牙设备发送一个开灯的参数数据 ,  1：代表开灯var writeValue ="1";this.writeBLECharacteristicValue(writeValue)},
//关灯
guandeng() {// 调用写入信息的方法 向蓝牙设备发送一个关灯的参数数据 ,  0：代表关灯var writeValue ="0";this.writeBLECharacteristicValue(writeValue)},
writeBLECharacteristicValue(writeValue) {// 向蓝牙设备发送一个0x00的16进制数据// let buffer = new ArrayBuffer(1)// let dataView = new DataView(buffer)//  dataView.setUint8(0, 0)//调用hex2buffer（）方法，转化成ArrayBuffer格式console.log('获取传递参数writeValue的数据为=====',writeValue)var buffer =this.hex2buffer(writeValue);console.log('获取二进制数据',buffer)//向低功耗蓝牙设备特征值中写入二进制数据。wx.writeBLECharacteristicValue({deviceId: this._deviceId,serviceId: this._serviceId,characteristicId: this._characteristicId,value: buffer,success (res) {console.log('成功写数据writeBLECharacteristicValue success', res)//如果 uni.writeBLECharacteristicValue 走 success ，证明你已经把数据向外成功发送了，但不代表设备一定就收到了。通常设备收到你发送过去的信息，会返回一条消息给你，而这个回调消息会在 uni.onBLECharacteristicValueChange 触发},fail(res) {console.error('失败写数据getBLEDeviceCharacteristics', res)}})
},
//断开与蓝牙低功耗设备的连接。closeBluetoothAdapter() {wx.closeBluetoothAdapter()this._discoveryStarted = false},
})

5.疑难点

1.如果你不确定写入的特性服务值可以通过（安卓）蓝牙助手获取特性值 deviceId（mac地址）、serviceId、characteristicId（苹果手机）蓝牙助手获得特性值deviceId（uuid地址）、serviceId、characteristicId  

注意：手机品类不同获取的deviceId的名称不同，但serviceId、characteristicId，是相同的

1.安卓手机（蓝牙助手获取的信息）

2.苹果手机（蓝牙助手）获取的信息

FFF0代表的serviceId全称：0000FFF0-0000-1000-8000-00805F9B34FB

FFF3代表的characteristicId全称：0000FFF3-0000-1000-8000-00805F9B34FB

最后：

祝愿你能一次成功
（代码直接复制粘贴到你的小程序中，替换下你自己设备的写入特性serviceId值）,
就可以测试了
最后如果还满意，记得点下赞、收藏加关注、我也好回关，相互进步！！！！！！！!！！