Arduino LED Dimmer: Part 2

So, where were we? Oh yes, I had built the web of things into what I wanted and it was time to extract the circuit from the prototyping tools.

Breadboard Prototype

Before I can design a PCB, I need to know exactly what the circuit is. Currently the Arduino side of it is still a ball of electronics wrapped in a user friendly board with all kinds of additional features. Needless to say, there’s a lot on there that I don’t need or can move off board. Like the USB/Serial converter chip, I can get a cable with that in it for when I do want to reprogram it so I don’t need that. If I do want to use the serial port for any prolonged time, which I probably will do, it’ll be to the Raspberry Pi, and I can do that with only a couple of resistors.

Time to break out the breadboard! I simply followed the instructions on the Standalone Arduino page, and the TLC5940 library page to assemble the circuit. The only differences are an additional button on the arduino digital “pin 2” (physical pin 4) which happens to be interrupt 0, and I’m using a single 16Mhz oscillator part rather than a crystal and pair of capacitors (the little blue disc).

Breadboard Prototype
Breadboard Prototype - Left to right: Empty Arduino board used as 5vdc source, Stand-alone Arduino circuit using the removed chip, and the TLC5940 circuit connected to it.

Look at them shine!

The button on the left is just the reset button, the button on the right is connected to interrupt 0 and changes the controller’s mode, similar to those single-button controller boxes you get on strings of christmas lights. Of course, being Arduino based, this one will blow those out of the water!

I love the random colours you get just from using RGB LEDs and the “Fades” example sketch that comes with the Arduino TLC5090 library. It’s not ideal like that since the red, green and blue LEDs inside the package all have slightly different specs. But for the purposes of creating some funky lighting effects, it’ll do. I’m not looking for precision colour matching right now. I’ll save that for later, and for when I have some better LEDs!

Well that was fun! But this isn’t a PCB and I’ve got a long way to go yet, so I really should stop staring at that and get on with getting to grips with some PCB design software!