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360 Flex - Day 1 (Sunday) - Live Blogging

We just had a great breakfast at Peggy Sue’s Dinner…and moved over to the Ebay Headquarters where the conferences is about to start.

I’ll be taking notes during the day and updating this page as we go one.

UPDATE: Now that I typed all that I realized that Justin put up the slides and code on his blog: http://blog.classsoftware.com/.

Connecting Arduino Hardware to Flex: Justin Mclean

twitter: justinmclean
Justin is from Sydney, Australia.


So we’ll go through the followings:

So Justin gave each attendee one board and a set of components. The board is open source hardware. I think that’s pretty cool. Feels like the hardware kit I bought for my 6 years son. The board is $25 and with all the components it’s about $40.


The hardware is provided to all participants by sparkfun.com




Also install the serial driver: FTDIUSBSerialDriver_10_4_10_5_10_6

Other Hardwares



First Program

int ledPin = 13; // LED connected to digital pin 13

// The setup() method runs once, when the sketch starts
void setup() {
// initialize the digital pin as an output:
pinMode(ledPin, OUTPUT);

// the loop() method runs over and over again,
// as long as the Arduino has power

void loop()
digitalWrite(ledPin, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(ledPin, LOW); // set the LED off
delay(1000); // wait for a second

Now this will make the led blink:


Circuit Basics

Digital Inputs/Outputs


It’s actually C++…What?! At a Flex conferences :-)

Setup Function





Debugging ia Serial Port

Blinking LED

Same program that the first program but this time we just set the led to the pin 3 which is connected to the board.

Digital Inputs

Connect Switch

Now switches have three states (on, off, and in between) to the board needs to be wired to take that into account so you can program it accordingly. We added a very high resistence (10k) next to switch to ensure that the switch reports 0V when not clicked.

int led = 3;
int button = 4;

void setup() {
pinMode(led, OUTPUT);
pinMode(button, INPUT);

void loop() {
if (digitalRead(button) == HIGH) {
digitalWrite(led, HIGH);
} else {
digitalWrite(led, LOW);

So let’s look at the wiring and how the switch operates:

Internal Pullup Resistors

So there is something like the 10K resistor built-in the board to avoid using an extra resistor on the board to make sure the switch values are on or off.

Switch Issues

Analog Inputs & Potentiometer

int led = 3;
int pot = 0;

void setup() {
pinMode(led, OUTPUT);

void loop() {
int value = analogRead(pot);
digitalWrite(led, HIGH);
// Set delay based on analog input
digitalWrite(led, LOW);

So now when the potentiometer is turned to the right a value of 1023 is returned and the lights blinks on and off for about 1 seconds. Turning to the left makes the delay shorted (down to 0) and you can get it to run blink really fast.



This is a great full day tutorial and everyone seems to have fun. It’s pretty basic, but it’s the first time I program hardware.

Now we are writing fadeIn and fadeOut functions and get the light to pulse on and off

void fadeIn(int led) {
  for (int i=0; i<256; i++) {
    analogWrite(led, i);

void fadeOut(int led) {
  for (int i=255; i >= 0; i--) {
    analogWrite(led, i);

void loop() {

Now we replace the light sensor by a temperature sensor. There are also air quality sensors, breathalyzers.


Communication between Flex and Arduinos.

Firmata is an Arduino library that support a binary protocol over serial interface. It’s Bi-directiona. Use version 2.

In the Arduino IDE let’s load the StandardFirmata program (File|Examples|Firmata|StandardFirmata). It’s a 286 lines program similar to the code we wrote so far, but more complex.

Server Proxy

From http://arduino.cc/en/Main/Software the server proxy (end of page)

To configure proxy first find what your serial device is.
In terminal do: ls /dev/cu*


Then add this line to your serproxy.cfg:

Then we just start the server proxy:
$ ./serproxy
Serproxy – ©1999 Stefano Busti, ©2005 David A. Mellis – Waiting for clients

Now in Flex you need to add the as3glue code (http://code.google.com/p/as3glue/) then you can drive arduino as follows:

private var arduino:Arduino = new Arduino();

private function init():void {
	arduino.addEventListener(ArduinoEvent.FIRMWARE_VERSION, turnLedOn);			

private function turnLedOn(event:ArduinoEvent):void {
	arduino.setPinMode(13, Arduino.OUTPUT);
	arduino.writeDigitalPin(13, Arduino.HIGH);

A qik look at the class room in the middle of coding their Flex app to drive their Arduino device:

Now we are going to write some Flex code to have some buttons that turn on/off some functions of the board.

private var arduino:Arduino = new Arduino();
private const pin:int = 3;
private const button:int = 4;

private function arduinoInit(event:Event):void {
	arduino.setPinMode(pin, Arduino.OUTPUT);
	arduino.setPinMode(button, Arduino.INPUT);
	arduino.addEventListener(ArduinoEvent.DIGITAL_DATA, buttonChanged);

private function buttonChanged(event:ArduinoEvent):void {
	if (event.pin==button) {
		event.value == Arduino.HIGH ? turnOn() : turnOff();

private function turnOn():void {
	arduino.writeDigitalPin(pin, Arduino.HIGH);

private function turnOff():void {
	arduino.writeDigitalPin(pin, Arduino.LOW);

Thanks Justin, great talk!

Fork me on GitHub