Arduino project(s)

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Soldering for hot air balloons complete

Thu, 29 Jan 2009 21:24:30 -0600

I used a RBBB mounted on a soldered breadboard. Also, two RJ45 connectors on SparkFun breakout boards. That will make a clean connection for the wires going up to the ceiling. I had originally planned on using screw terminals, but then I decided to use wire pairs (signal, gnd) and needed twice as many connections. There was enough unused space for every other pin to be a ground with these breakouts.

Prototype complete

Fri, 25 Apr 2008 10:51:46 -0500

I finished the prototype with all the features I wanted:
Light sensor to turn the LEDs off after the room lights are turned off.
Button to set the room darkness threshold, since I don’t want to have to reprogram the chip in the future.
Six LEDs with flickering brightness.
One steady LED for a differently shaped balloon, which will be used for the status display as well (blink to indicate setting the threshold, as well as to indicate that it noticed the lights went out).

Flickering LEDs proof of concept

Fri, 25 Apr 2008 08:38:32 -0500

My first project is to light a string of papier-mâché hot air balloons. I was just going to light them with some LEDs, but then I heard about the Arduino and wanted to make something more exciting. I got a starter kit from adafruit.com and got to work.

This is the first proof of concept of making the LEDs flicker. Later I’ll add a light sensor to start a sleep timer that will turn the balloons off after a half hour.

Here’s the sketch that runs what you see above:

/*
* randomly flickering LEDs
*/

int ledPin[] = {
5, 6, 9, 10, 11}; // pwm pins only
int ledState[5]; // last state of each led
long randNumber;

void setup() {
for (int i=0; i<=4; i++){ // set each led pin as an output
pinMode(ledPin[i], OUTPUT);
}
randomSeed(analogRead(0)); // seed the rnd generator with noise from unused pin

for (int i=0; i<=4; i++){ // init each led with a random value
ledState[i] = random(20, 201);
}
}

void loop(){
for (int i=0; i<=4; i++){ // for each led:
analogWrite(ledPin[i], ledState[i]); // set the pwm value of that pin determined previously
randNumber = random(-40, 41); // generate new random number and add that to the current value
ledState[i] += randNumber; // that range can be tweaked to change the intensity of the flickering
if (ledState[i] > 200) { // clamp the limits of the pwm values so it remains within
ledState[i] = 200; // a pleasing range as well as the pwm range
}
if (ledState[i] < 10) {
ledState[i] = 10;
}
}
delay(100); // the delay between changes
}