Traffic Light Disco-Light Project

[james_hartt]

Hi there,

My flatmate does set design, he recently acquired a traffic light, I rigged up an old computer power supply and have the three 50W halogens working perfectly all at the same time with bog standard switches.

As a summer project I'm interested in fiddling around with some PICs and get the traffic light working autonomously, I am a Electronic and Electrical Engineering graduate so feel free to throw any theory/jargon at me.

My project is simply, I want to use some sort of buck converter to power all three separately through a PWM of an Arduino or similar (that side I'm completely confident with and am also planning to use one of their cellular GSM shields to have anyone text in and change its lighting), so I can essentially dim the lights and have them coming on and off and everything in between and obviously create an amazing lighting feature. I wish to get it done by the beginning of july so we can use it in a massive house party before our tenancy ends!

So what I need is any advice as what to use, if there are any cheap "black box" alternatives that will suit my needs or will I have to create a buck convertor with a FET, inductors, capacitors and diodes etc. or even an approach I have not thought of.

If so, any devices, topologies, rough values of components, sizes, any things to be aware of, tips etc.
For example sometimes that power supply does trip if you don't makes sure all of the lights are off before turning it on, which is sort of understandable but haven't bothered really looking to solve it.

Would be interested to know if anyone could save me some time!

The specs are as follows:

50W 12V(rms) halogen bulbs
450W power supply with all the rails of a computer power supply with very adequate current abilities

Any information that is missing just let me know and I'll help out.

If I get onto the next step I will make sure anyone that helps is filled in on how it goes!

Thank you!  :)

Jim