Arduino LED Light bug
I have recently started a project to build automated stair lights using RGB LED strip. I was intending to re-use an Arduno board that I built to control some christmas lights a couple of years ago, but quickly realised that the current draw of the RGB lights was probably at the maximum of the circuit that I had built. So instead I decided to build a 'mood' light go to behind my monitors in my office that would provide ambiant lighting
The curcuit basics
The RGB LED Light strip that I have is 12v and the Arduino is 5v. To control the lights I am using a home built Arduino, with a ULN2003A Darlington Array to control the 12v LED lights. The ULN2003A has 8 channels, each of which can sink 500mA. To drive the LED strips I only need 3 channels; Red, green and Blue; so I have doubled up the channels to provide a maximum of 1A per channel.
Each channel is driven from a digital output pin of the Arduino through the ULN2003A, using Pulse Width Modulation (PWM) to allow fading of the indivudal channels, and therefore mixing of the colours.
To allow me to change the colours I have added three 10K potentiometers linked to analog inputs on the Arduino.
I then went looking for a case to put it all in.....and decided on one of my sons old toys, an electronic bug.
The old guts were soon removed and the arduino circuit board installed. I then drilled three holes in the lid for the potentiometers, and we were done :)