Neurolab data transfer – Establishing serial communication between Arduino and Android
In the development process of the Neurolab Android, we needed an Arduino-Android connection for transfer of data from datasets which included String and float data type values. In this blog post, I will show you how to establish a serial communication channel between Android and Arduino through USB cable through which we can transmit data bidirectionally. Requirements Hardware: Android PhoneArduino (theoretically from any type, but I’ll be using Arduino Uno)USB 2.0 Cable Type A/B (for Arduino)OTG Cable (On The Go)Normal USB Cable (for transferring the data from Android Studio to your phone) Software: Android StudioArduino IDE Wiring and Setup Wiring must be established in the following way: Figure: Android-Arduino Setup Working on the Android Side We would be using the UsbSerial Library by felHR85 for establishing serial communication. 1. Adding the dependency: a) Add the following line of code to your app level build.gradle file. implementation "com.github.felHR85:UsbSerial:$rootProject.usbSerialLibraryVersion" Note: The ‘usbSerialLibraryVersion’ may change from time to time. Please keep your project with the latest library version. Updates can be found here. b) Add jitpack to your project.build.gradle file. allprojects { repositories { jcenter() maven { url "https://jitpack.io" } } } 2. Working with Arduino: We need to program the Arduino to send and receive data. We achieve that with the help of Arduino IDE as mentioned above. Verify, compile and upload a sketch to the Arduino for sending and receiving data. If you are a complete beginner in Arduino programming, there are example sketches for this same purpose. Load an example sketch from under the communication segment and choose the serial communication sketch. Here, we will be working with a simple sketch for the Arduino such that it simply echoes whatever it receives on the serial port. Here is sketch code: // the setup routine runs once when you press reset: void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); } // the loop routine runs over and over again forever: void loop() { char incomingByte; // If there is a data stored in the serial receive buffer, read it and print it to the serial port as human-readable ASCII text. if(Serial.available()){ incomingByte = Serial.read(); Serial.print(incomingByte); } } Feel free to compile and upload it to your own Arduino. 2. Working with Android: Firstly, we need an USBManager instance initialized with the system service - ‘USB_SERVICE’. This needs to be done in an Activity (preferably main) so that this instance can be passed to the Communication Handler class, which we are going to create next.Now, we will be working with a class for handling the serial communications with our Android device and the Arduino board. We would pass the USBManager instance to this class wherein work will be done with that to find the USBDevice and USBDeviceConnection Starting with, we need to search for any attached Arduino devices to the Android device. We create a method for this and use the ‘getDevicesList’ callback to achieve this in the following way: public void searchForArduinoDevice(Context context) { HashMap usbDevices…