Nodejs module to read from ez430-chronos USB dongle

README.md

ez430

EZ430-Chronos on node.js

• used by Chronos node-red module

index.js

'use strict';

var serialport = require('serialport'),
    SerialPort = serialport.SerialPort, // localize object constructor
    events = require('events'),
    fs = require('fs'),
    util = require('util');

var startAccessPoint = new Buffer([0xFF, 0x7, 0x03]),
    stopAccessPoint = new Buffer([0xFF, 0x9, 0x03]),
    accDataRequest = new Buffer([0xFF, 0x08, 0x07, 0x00, 0x00, 0x00, 0x00]),
    devicePath = '/dev/ttyACM0';        // temp fix

var DEBOUNCE = 50;

function ez430(options) {
  var sp, self = this;

  options = options || {};
  events.EventEmitter.call(this);

  try {
    fs.statSync(devicePath);
  } catch (e) {
    throw new Error('device not found');
  }
  sp = new SerialPort(devicePath, { baudRate: 115200 }, function(){
    console.log('Chronos serial port at', devicePath);
  });

  this.close = function () {
    sp.write(stopAccessPoint);
    sp.close();
  };

  sp.on('open', function () {
    console.log('ez430: start ap..', startAccessPoint);

    sp.write(startAccessPoint);
    sp.write(accDataRequest);

    sp.on('data', function (data) {
      var timeout = DEBOUNCE,
          x, y, z, b = 0, on,
          buf = new Buffer(data);
      if (data.length >= 7) {
        b = buf.readInt8(3);
        x = buf.readInt8(5);
        y = buf.readInt8(4);
        z = buf.readInt8(6);
        on = (buf[3] === 1 || buf[3] === 18 || buf[3] === 34 || buf[3] === 50);
        if (on) {
          console.log('b:' + b + ', x:' + x + ', y:' + y + ', z:' + z);
          self.emit('chronosData', b, x, y, z);
        }
      } else {
        console.log((new Date()).getTime() + ' invalid data', buf);
      }
      setTimeout(function () {sp.write(accDataRequest);}, timeout);
    });
    sp.on('close', function (err) {
      console.log('port closed');
      self.emit('close');
    });
    sp.on('error', function (err) {
      console.log('error', err);
      sp.write(stopAccessPoint);
      self.emit('error', err);
    });
  });
}

util.inherits(ez430, events.EventEmitter);
module.exports = ez430;

package.json

{
    "name": "ez430",
    "version": "0.0.1",
    "description": "ez430 on node.js",
    "main": "index.js",
    "engines": {
        "node": "0.10.x"
    },
    "keywords": [
        "ez430",
        "ezChronos"
    ],
    "author": {
        "name": "Swapan Sarkar",
        "email": " <[email protected]>",
    }
    "license": "MIT",
    "readmeFilename": "README.md",
    "dependencies": {
        "serialport": "1.0.x"
    }
}