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LED Controller

KRe8ive

May 26, 2012
14
Joined
May 26, 2012
Messages
14
Hi,

I have recently wired up an array of RGB LED lighting on my car. I have it in 8 different sections and want to make a controller that gives me full RGB Colour mixing with intensity control over each section individually. So based on this I figure I need 24 individual outputs. The LED's are all set up common anode. I have looked at some controllers available on the market, and while some do exist they can be costly, I would like to think that I could make something cheaper and also enjoy the experience of making it.

Then there is the second part. As a control device for it i was wanting to look at using my iPhone / iPad. Was hoping to work an app on it to select the area of the car then select the colour or be able to make entire car a colour. Does anyone know of any customisable apps that I could then use to talk to the control device?

I did consider using an arduino, but it lacks enough PWM pins.

Each set of LEDs is running no more than approx 3amp per colour (have not tested the exact power draw) and there is the possibility of every one having all colours on at once, so the controller would need to be able to handle the load.
Being on my car it is obviously running at 12v +- the usual allowances, max of approx 14v,

I Hope I have Given enough information here.

Cheers
Kurt
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
A microcontroller running fast enough and programmed in C or asm should be able to manage 24 soft PWM outputs. That is the way I would go, with a MOSFET for each of the 24 signals to handle up to 3A (choose one rated at 5 or more).

If you use MOSFETs with very low on resistance you might even be able to get by without heat sinking them. A TO220 case can handle about 1W, so you would need an on resistance of about I^^/R =1. or 1/9, or say 0.1 Ohms.

As for controlling it from an iPhone. That is a lot more compicated. You would need something like a bluetooth module to interface to the micro and programming on both the iphone and the micro to do this.

Bob
 
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