Spark Core UDP Echo

README.md

UDP Echo Sketch for Spark Core

A simple UDP echo program for the Spark Core Arduino based device. You can send a single byte (ie. 'a') of data and have it sent back. This program serves no real practical application, but can be used to learn and tinker with UDP and inter-device communication.

Testing UDP

You can test sending and receiving UDP packets using the Packet Sender application, available for Windows, Mac, Ubuntu and Andriod.

simple-udp-echo.ino

// UDP Port used for two way communication
unsigned int localPort = 8888;

// An UDP instance to let us send and receive packets over UDP
UDP Udp;

void setup() {
    // Initialise UDP
    Udp.begin(localPort);
    
    // Print your device IP Address via serial 
    Serial.begin(9600);
    Serial.println(Network.localIP());
}

void loop() {
    // Check if data has been received
    if (Udp.parsePacket() > 0) {
        
        // Read first char of data received
        char c = Udp.read();
        
        // Ignore other chars
        Udp.flush();
        
        // Store sender ip and port
        IPAddress ipAddress = Udp.remoteIP();
        int port = Udp.remotePort();
        
        // Echo back data to sender
        Udp.beginPacket(ipAddress, port);
        Udp.write(c);
        Udp.endPacket();
    }
}