arduivis

NodeJS - Model #2: Input

Abstract

This is an example of how to send a single stream of data from MaxMSP to a NodeJS server using an Arduino as a serial communication hub.

Arduino

 
/* 

~~~~~~~ arduivis - NodeJS ~~~~~~~
~~~~~~~~ model#2: input ~~~~~~~~~

nodejs: arduivis_nodejs_model2_input.maxpat

This is an example of how to send a single stream of
data from MaxMSP to a NodeJS server using an Arduino.

synthesized by Christopher Konopka

This example code is in the public domain.

*/

void setup() 
{ 
  // Create/open serial port
  Serial.begin(9600);   
}

void loop() 
{
  // Slider from MaxMSP 
  int maxmspSlider;

  // Parse incoming MaxMSP slider values
  // from MaxMSP, through Arduino, to NodeJS server    
  maxmspSlider = Serial.parseInt();  
  
  // Write messages from MaxMSP to serial buffer
  // These messages can be obtained using a NodeJS server
  Serial.println(maxmspSlider);
}

NodeJS

var   splitData,
      myPort,
      app,
      servi,
      servi       = require('servi'),        // include the servi library  
      app         = new servi(false);        // create new servi instance    
      serialport  = require('serialport'),   // include serialport library
      SerialPort  = serialport.SerialPort,   // create new serialport instance 
      portName    = process.argv[2],         // get port name from the command line
      latestData  = 0;                       // latest data saved from the serial port

// configure the server's behavior:
app.port(8080);               // port number to run the server on
app.serveFiles("public");     // serve all static HTML files from /public
app.route('/data', sendData); // route requests for /data to sendData() function
app.start();                  // now that everything is configured, start the server:

myPort = new SerialPort(portName, { 
   baudRate: 9600,
   // look for return and newline at the end of each data packet:
   parser: serialport.parsers.readline("\r\n") 
 });   
 
// serial even definitions
myPort.on('open', showPortOpen);  
myPort.on('data', saveLatestData); 
myPort.on('close', showPortClose);
myPort.on('error', showError);

// The port is open notification
function showPortOpen() {
   console.log('port open. Data rate: ' + myPort.options.baudRate);
}

// captures incoming from Max, through Arduino
function saveLatestData(data) {
   latestData = data;

   // split the incoming data into array for easier access
   var splitData = latestData.split(" ");

   // collective array of all of the incoming data
   console.log(splitData);
}

// closed port notification
function showPortClose() {
   console.log('port closed.');
}

// serial error notification
function showError(error) {
   console.log('Serial port error: ' + error);
}

// server function
function sendData(request) {  
   // print out the fact that a client HTTP request came in to the server:
   console.log("Got a client request, sending them the data.");
   // respond to the client request with the latest serial string:
   request.respond(latestData);
}

MaxMSP