Android: RS232 Serial Communication with android device

Android: RS232 Serial Communication

Introduction

RS232 is a standard serial communication protocol widely used in industrial automation, robotics, and other applications. This article discusses how to establish RS232 communication between an Android device and external devices.

Hardware Requirements

• Android device with a USB Type-C or Micro-USB port.
• USB to RS232 converter cable.
• RS232 compatible device.

Software Requirements

• Android Studio with the latest SDK.
• Java programming language.
• Suitable RS232 library (e.g., Android Serial Port API).

Choosing an RS232 Library

Implementation Steps

1. Install Required Libraries

Add the chosen RS232 library to your Android project’s build.gradle file.

dependencies {
    implementation 'com.github.felHR85:UsbSerialForAndroid:10.0.0'
    // Other dependencies
}

2. Create an Instance of the Serial Port Object

Create an instance of the chosen library’s serial port object.

SerialPort serialPort;
try {
    serialPort = new SerialPort(devicePath, baudrate); // Replace with your device path and baudrate
} catch (IOException e) {
    // Handle the exception
}

3. Open and Configure the Serial Port

Open the serial port for communication and set the desired parameters (baud rate, data bits, parity, stop bits).

OutputStream outputStream = serialPort.getOutputStream();
InputStream inputStream = serialPort.getInputStream();
// Set baud rate and other parameters

4. Send and Receive Data

Use the output stream to send data to the connected device.

byte[] data = new byte[] { 0x01, 0x02, 0x03 };
outputStream.write(data);
outputStream.flush();

Use the input stream to read data from the connected device.

byte[] buffer = new byte[1024];
int bytesRead = inputStream.read(buffer);
if (bytesRead > 0) {
    // Process the received data
}

5. Close the Serial Port

Close the serial port after communication is complete.

serialPort.close();

Example Code (Using Android Serial Port API)

package com.example.rs232communication;

import android.os.Bundle;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.felhr.usbserial.UsbSerialInterface;
import com.felhr.usbserial.UsbSerialProber;
import com.felhr.usbserial.driver.UsbSerialDriver;
import com.felhr.usbserial.driver.UsbSerialPort;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.Executors;

public class MainActivity extends AppCompatActivity {

    private TextView textView;
    private UsbSerialPort serialPort;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);

        // Find the USB Serial Driver
        List availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers();
        if (availableDrivers.size() > 0) {
            UsbSerialDriver driver = availableDrivers.get(0); // Choose the first driver

            try {
                serialPort = driver.getPorts().get(0); // Choose the first port
                serialPort.open();
                serialPort.setParameters(115200, 8, UsbSerialPort.PARITY_NONE, 1);

                serialPort.setDTR(true); // Set Data Terminal Ready

                serialPort.read(mCallback); // Register a callback to read data

            } catch (IOException e) {
                // Handle the exception
            }
        } else {
            // No USB Serial Driver found
        }
    }

    private UsbSerialInterface.UsbReadCallback mCallback = new UsbSerialInterface.UsbReadCallback() {
        @Override
        public void onReceivedData(byte[] data) {
            final String receivedData = new String(data);
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    textView.setText("Received: " + receivedData);
                }
            });
        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        try {
            serialPort.close();
        } catch (IOException e) {
            // Handle the exception
        }
    }
}

Received: [data received from the device]

Conclusion

This article provided a comprehensive guide on establishing RS232 communication between an Android device and external devices. By following these steps and choosing a suitable RS232 library, you can successfully implement serial communication capabilities in your Android applications.