MavLinkNodeJSTest.js

var mav         = require("./mavlink_v10_ardupilotmega.js");
var mavProtocol = new MAVLink( null, 252, 1 );

var serverPort  = 6000;             // local sever listening port
var remotePort  = -1;               // this is set by the first HEARBEAT msg received from the drone
var remoteIp    = '192.168.1.200';  // drone IP
var dgram       = require('dgram');
var server      = dgram.createSocket('udp4');


// Server
// ---------------------------------------------------------------- //

server.on('listening', function () {
    var address = server.address();
    console.log('UDP Server listening on ' + address.address + ":" + address.port);
});


server.on('message', function (message, remote) { 
    
    // decode the MAVLink msg, this function should return the msg or null
    decodedMsg = mavProtocol.decode(message);

    // wait for the first HEARTBEAT message to send the remotePort
    // this is used to send back messages to the drone
    if ( decodedMsg && decodedMsg.name == "HEARTBEAT" )
    {
        // this is the first HEARTBEAT msg received
        // log and send a test message to the drone
        if ( remotePort < 0 )
        {
            remotePort = remote.port;
            console.log('set udp port: ' + remote.port );
            sendMAVLink( new mav.messages.autopilot_version_request(1, 1) );
        }
        else
            remotePort = remote.port;
    }

    // Log incoming messages except HEARTBEAT
    if ( decodedMsg && decodedMsg.name != "HEARTBEAT" )
        console.log( decodedMsg );
    else if ( !decodedMsg )
        console.log( 'Decode Error: ');
});

server.bind(serverPort);	


// MAVLink
// ---------------------------------------------------------------- //

function sendMAVLink( msg )
{
    buff = new Buffer(msg.pack(mavProtocol));
    
    mavProtocol.seq                 = (mavProtocol.seq + 1) % 256;
    mavProtocol.total_packets_sent  +=1;
    mavProtocol.total_bytes_sent    += buff.length;

    if ( remotePort > 0 )   // wait for the drone to send the HEARTBEAT
    {    
        server.send( buff, remotePort, remoteIp, function(err, bytes) {
            if (err) {
                console.log('ERROR! ' + err );
                throw err;
            }
        });
    }
    else
    {
        console.log('MAV not ready!');
    }
}