Design DIY LED Driver

[Liam Bellingham]

Hey guys,

This is my first post so a little about me first. I am 15 years old and I love lighting! I do a lot of voluntary work for Hillsong Melbourne and my school. I like making things like hazers and camera accessories like jibs and steadycams.

My friend has a bunch of traxon architectural light bars with 3 different colour temps. He gave me one to pull apart and see how they work. I found out they run on 48v and use cat6 and rj-45 plugs for control. It's a simple 1-, 2-, 3-, 1+, 2+, 3+ on the pinout. This is where the problem started. I need a way to control 48v with DMX. I don't have a big budget. I have no idea how much current they really use, but is says 350ma on the side of the box. My idea was to get 4 12v RGB led controllers from ebay and wire them in parallel and address them the same. My heart screams that this won't work my my basic understanding of electronics says it will. I looked online and I can't find anything on the LED bars themselves or anything like 48v led DMX drivers. My budget is about $100 aud. I can solder if necessary, with some sort of kit with clear instructions. My uncle is an electrician so I can get some help with 240v stuff.

Thanks, Liam Bellingham

 

[Mac Hosehead]

I am somewhat doubtful that your solution to drive these LEDs will work. If it did you would need 4 separate power supplies.

I suggest you pose your question at some forums that are more oriented toward do-it-yourself. There are DIY people at Christmas lighting forums that are knowledgable in electronics, familiar with driving LEDs, and familiar with DMX control protocols. They also hack existing products. You could say it's for a Christmas display but I think they would help you regardless. Here are some I know of:

http://auschristmaslighting.com/forums/
http://www.diychristmas.org/
http://doityourselfchristmas.com/

-MH

 

[theatricalmatt]

48V seems high for an LED; are they ganged together on a circuit board?

You might look into Arduino, which allows for PWM dimming off of (most) Arduino boards. Typically the Arduino boards only provide much lower voltage (3.3 or 5VDC, I believe) and also limit the amount of current they can pass; but you could use the Arduino to control a 48V driver. The Arduino boards are relatively inexpensive and commonly available on the Internet; you can even make your own.

You would also need to write some code to read DMX in and correctly interpret it, but that's fairly trivial.

 

[microstar]

Would something like this work:
http://shop.ledwholesalers.com/index.php?route=product/product&product_id=152

 

[JD]

My idea was to get 4 12v RGB led controllers from ebay and wire them in parallel and address them the same.

Parallel will not increase the voltage.

 

[Liam Bellingham]

Thanks guys for your response!
I messed up when I said parallel. I meant series.
All I can remember is that there are 4 pcbs in the fixture, each pcb drawing 12v, 48v in total.
I will look into the christmas light stuff, it looks promising.

 

[soundman]

I just built an LED driver with Arduino. My LED bars were 24 volts and I used this shield. I also had to buy a separate PSU to drive the LEDs With an enclosure and some other supplies it was around $75 all in. I just wanted to be able to dim each color individually and it took maybe half an hour of programming and trouble shooting to get it working. I think they make DMX shields as well.