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。
- 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
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。
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。
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。
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