基于Android与STM32的宿舍自动开门神器

一、概述

一直想做一个，能够自动开宿舍门的东西，前几天看到网上的一个帖子，有人已经做过了，用的是电磁铁，我就开始动手了。目的在于，可以免除带钥匙，可以在床上开门。

二、材料

• STM32F103C8T6
• C-60-12直流电源（OUTPUT：+12v）
• LM2596降压模块（OUTPUT：+5v）
• BT-05蓝牙4.0模块
• 电磁铁推拉式长行程35mm微型直流12v24v220V牵引吸力6kg电磁门锁 http://b.mashort.cn/S.b587vF （注意，要选用大吸力的电磁铁，否则无法拉开门闩）
• 继电器模块
• 细线

三、思路

主要想法就是通过手机蓝牙串口，发送到BT-05蓝牙串口模块，然后单片机读取发送的数据，若校验成功，则给继电器高电平，电磁铁通电，拉开门闩。主要分为STM32部分和Android部分。

四、实现

（一）、STM32

这里代码很简单，主要就是串口通讯。直接贴代码：

while (1){    delay_ms(10);    while (!(USART_RX_STA&0x8000))    {        continue;    }    USART_RX_STA = 0;    if ((USART_RX_BUF[0] != '4')        ||(USART_RX_BUF[1] != '5')        ||(USART_RX_BUF[2] != '1'))    {        continue;    }    LED = !LED;    DOOR = 1;    USART_RX_STA = 0;    delay_ms(1000);    delay_ms(1000);    DOOR = 0;}

没有什么好说的，很简单。

（二）、Android

原本，这个也很简单，就是蓝牙串口，用之前的代码，很简单的。但是，我有一个更高的需求，那就是：越简单越好，越少点击次数越好，所以我想，如果能添加一个桌面小部件，点一下桌面小部件，就发送蓝牙串口消息，那岂不方便很多，都不需要进入activity，于是我就学习了半天关于桌面小部件（Widget）的相关知识。其实也不难，先新建一个widget，然后在继承自AppWidgetProvider的类，默认是NewAppWidget这个类里面的updateAppWidget函数里面，为button添加事件。

static void updateAppWidget(Context context, AppWidgetManager appWidgetManager,                            int appWidgetId) {    CharSequence widgetText = context.getString(R.string.appwidget_text);    RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.new_app_widget);    Intent intentservice = new Intent();    intentservice.setClass(context, AppWidgetService.class);    PendingIntent pendingIntent = PendingIntent.getService(context, 0, intentservice, 0);    views.setOnClickPendingIntent(R.id.button, pendingIntent);    appWidgetManager.updateAppWidget(appWidgetId, views);}

这样就为id为button的Button绑定了一个service，点击button，就会启动AppWidgetService这个Service。下面我们来看一下AppWidgetService，我们的这个程序的最主要的部分就在这个服务里面。
package com.zhang.door;

import android.app.Service;import android.bluetooth.BluetoothDevice;import android.content.BroadcastReceiver;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.content.ServiceConnection;import android.os.IBinder;import android.util.Log;import android.widget.Toast;import static android.content.ContentValues.TAG;public class AppWidgetService extends Service {    private final static String TAG = DeviceControlActivity.class.getSimpleName();    public static final String EXTRAS_DEVICE_NAME = "DEVICE_NAME";    public static final String EXTRAS_DEVICE_ADDRESS = "DEVICE_ADDRESS";    private String mDeviceName = "451";    private BluetoothLeService mBluetoothLeService;    private boolean mConnected = false;    private String mDeviceAddress = "00:15:83:00:77:AF";    public AppWidgetService() {    }    private final ServiceConnection mServiceConnection = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName componentName, IBinder service) {            mBluetoothLeService = ((BluetoothLeService.LocalBinder) service).getService();            if (!mBluetoothLeService.initialize()) {                Log.e(TAG, "Unable to initialize Bluetooth");            }            Log.e(TAG, "mBluetoothLeService is okay");            // Automatically connects to the device upon successful start-up initialization.            //mBluetoothLeService.connect(mDeviceAddress);            mBluetoothLeService.connect(mDeviceAddress);        }        @Override        public void onServiceDisconnected(ComponentName componentName) {            mBluetoothLeService = null;        }    };    private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            final String action = intent.getAction();            if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {                Log.e(TAG, "Only gatt, just wait");            } else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {                mConnected = false;            }else if(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action))            {                mConnected = true;//                ShowDialog();                Log.e(TAG, "In what we need");                mBluetoothLeService.WriteValue("451\r\n");                mBluetoothLeService.disconnect();                stopSelf();            }        }    };    @Override    public IBinder onBind(Intent intent) {        // TODO: Return the communication channel to the service.        Log.w(TAG, "onBind");        throw new UnsupportedOperationException("Not yet implemented");    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Log.w(TAG, "onStartCommand: hello world!");        Intent gattServiceIntent = new Intent(this, BluetoothLeService.class);        Log.d(TAG, "Try to bindService=" + bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE));        registerReceiver(mGattUpdateReceiver, makeGattUpdateIntentFilter());        Toast.makeText(getApplicationContext(), "开门", Toast.LENGTH_LONG).show();        return super.onStartCommand(intent, flags, startId);    }    @Override    public void onDestroy() {        super.onDestroy();        unbindService(mServiceConnection);        unregisterReceiver(mGattUpdateReceiver);    }    private void ShowDialog()    {        Toast.makeText(this, "连接上啦！", Toast.LENGTH_SHORT).show();    }    private static IntentFilter makeGattUpdateIntentFilter() {        final IntentFilter intentFilter = new IntentFilter();        intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);        intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);        intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);        intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);        intentFilter.addAction(BluetoothDevice.ACTION_UUID);        return intentFilter;    }}

在onStartCommand方法里面，绑定了BluetoothLeService，注册了mGattUpdateReceiver，在这里有一个回调方法onServiceConnected，当服务一旦绑定成功，在这个方法里面就会调用mBluetoothLeService的connect方法，尝试连接到蓝牙串口模块。如果连接成功，会进入BroadcastReceiver里面，如果连接上，就会嗲用mBluetoothLeService的WriteValue方法，发送”451\r\n”，然后蓝牙模块接收到，单片机就会处理，这时候电磁铁上电，门闩就被拉开了。

五、效果图

https://raw.githubusercontent.com/rty813/451door/master/demo.gif“” alt=”演示” title=”” />