public class PingService extends Service
{
    private InetAddress serverAddress;
    private Socket socket;

    @Override public int onStartCommand(Intent intent, int flags, int startID)
    {
        serverAddress = InetAddress.getByName(intent.getStringExtra("proximityAddress"));
        new TCPreceiver().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, this);
        return START_STICKY;
    }

    class TCPreceiver extends AsyncTask
    {
        InputStream inputStream;
        OutputStream outputStream;
        Context c;

        @Override protected Object doInBackground(Object[] objects)
        {
            c = (Context) objects[0];
            try
            {
                socket = new Socket(serverAddress, 4000);
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
                stopSelf();
                return null;
            }
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(c) //blabla, robienie notyfikacji
            startForeground(10, notificationBuilder.build()); //myślałem, że startForeground w tym miejscu powiąże AsyncTask z Servicem i nie zabije tego pierwszego, ale nie
            while (true)
            {
                try {
                    inputStream.read(//czytaj bajty z czujnika);
                            outputStream.write(//pisz bajty do czujnika);
                } catch(Exception e){/*wyjątki*/}
            }
        }
    }
}