I admit it: I'm a total geek. I love electronics, programming, 3D art, vintage Apple hardware, and whisky. I'm always juggling half a dozen projects. I also enjoy documenting it all: my successes, my failures, my experiences... and everything geeky along the way.


 
 
 
 
 

Fun with RGB LEDs | Kevin Rye.net - Main

Kevin Rye

Geek Extraordinaire. Yeh, I said it.

Fun with RGB LEDs

The SoundBox was a fun project. I learned a lot from it. But it’s a one trick pony and a total waste of the $30 worth of tech I ended cramming into that custom enclosure I made.

soundbox_final_assembly_0034

It would be a shame to waste such a nice looking enclosure. Since I’ve been playing around with the ATtiny, I thought it would be cool to cram it full of RGB LEDs and make a cool rainbow-colored night light for the kids’ room.

I know that the ATtiny, natively anyway, only supports 2 PWM pins. The core can be changed to support 3 PWM pins, but it takes some tweaking to pull it off. I might be able to modulate some RGB LEDS with one. In order to “pulse” RGB LEDs, you need to be able to modulate 3 pins for the red, green, and blue anodes of the LED.

If I can’t pull it off with an ATtiny, I can always use one of my handy-dandy Bare Bones Arduino widgets. Looks like they’re coming in handy already!

BBA version 1 widget

RGBs, relatively speaking, are pretty expensive. Some sites (cough)SparkFun(cough) charge $1.95 for one! Not happening. From my Word Clock build, I know that LEDs can be had for pennies from eBay if you’re willing to wait a week or two for a Hong Kong delivery. I hopped on eBay and secured a bag of 100 for $13.00. I even took the liberty of ordering 100 LED bezels for another $6 bucks. It took exactly 2 weeks for them to arrive. A small price to pay for saving over $200 dollars.

100 RGB LEDs 5mm

5mmLEDbezels_0072

I connected an LED to my Bare Bones widget and then modified the blink sketch to blink each of the red, green and blue anodes.

RGB LED on the BBA_0001

int red = 6; //red
int green = 7; //green
int blue = 8; //blue

int ground = 5;

void setup() {                
  pinMode(red, OUTPUT); 
  pinMode(green, OUTPUT); 
  pinMode(blue, OUTPUT);    
  pinMode(ground, OUTPUT);  
}

void loop() {
  digitalWrite(ground, LOW);

  //red
  digitalWrite(red, HIGH);   
  delay(500);               
  digitalWrite(red, LOW);    
  delay(500); 

  //green
  digitalWrite(green, HIGH);   
  delay(500);               
  digitalWrite(green, LOW);    
  delay(500); 

  //blue
  digitalWrite(blue, HIGH);   
  delay(500);               
  digitalWrite(blue, LOW);    
  delay(500); 
}

This should work pretty well as a test fixture for all 100 LEDs. I should be able to run through all of them in no time. I’m sure they all work, but I want to test them all just to make sure I didn’t receive any duds.



I started to dig in a bit and see what I could do with some color blending. I just modified the above sketch to turn on multiple pins at a time. I added a second LED just for fun.



Easy enough. I then started playing around with some PWM stuff to try and blend the colors from one to another. It’s not bad. It needs a little more work. I don’t think the red shows for as longs it should, but it’s a start.



It’s going to look pretty cool when there’s like 20 of these all going off at once!

I already started tinkering with the idea of making a ton of little RGB LED breakout boards for the Night Light. That way, I’ll be able to easy connect a good 20 or so LEDs together inside the enclosure without making a mess with the wiring. Not to mention it’ll be really difficult to solder 60+ resistors to the LEDs without everything falling apart. I can just picture the rats’ nest. Although the SoundBox enclosure is a pretty descent size, the arcade button takes up a lot of space. After I add a battery pack and the Arduino board, there probably won’t be a lot of real estate to work with. So it makes sense to keep everything as small and as tight as possible.

arcadebuttonspace

As far as the LEDs, I’m thinking abut putting 5 on each side, and 4 on the top. That’s a total of 24 LEDs. If I squeeze 8 on a PCB, I can get all 24 made with one OSH Park order. I jumped into Eagle and started to put together a board.

rgb oshpark brd render

The LEDs will go on one side and the resistors will go on the other. I can then just daisy chain them all together. It should be a very clean build.

rgb oshpark brd render back

I can then cut up the boards and mount them (hot glue) on the inside. I’ll drill holes for the LEDs and finish them with the nice little LED bezels I ordered.

rgb led layout idea1

I imagine the wiring for each side will look something like this:

led board wiring layout

Considering the PCBs from OSH Park are going to cost $17, it looks like this is going to be another “quick and easy” project that ends up costing me $30 bucks. I’m starting to think it’s the enclosure that’s at fault!

See this project from start to finish:
Fun with RGB LEDs
RGB Night Light
RGB Night Light Build