LED Par Can Take-apart
Today I received in the mail a Chauvet COLORsplash Jr. LED Par light. This is basically a spotlight that you can control the color of with a computer using the DMX protocol. I thought it’d be handy to have a general purpose color-controlled light for when I need to get an idea of how a certain effect might look.
The place I bought it from had it listed as a ’scratch and dent’ item and was selling it as a discount with the guarantee that the unit would work flawlessly. Unfortunately upon turning it on I found that three of the green LED’s were dark.
Giving the unit a couple of taps, I was able to get the three dark LED’s to flash on momentarily suggesting, ah ha!, a simple loose connection. Expecting a quick repair (and hoping to save myself the hassle of returning it) I took the unit apart and traced down the problem.
The problem unfortunately was more than a simple bad connection. The LEDs are wired up in series chains with three LED’s per chain and in one of those chains a LED had failed. Dead, stone cold, wouldn’t “voom” if you put 4-million volts through it, don’t ask me why it flashed on briefly at all because when I removed it from the circuit it no worky. I swapped it out for a 5mm green LED that I had but the color simply did not match with the other green LEDs (not even close) so I swapped it back for the dead one.
Resigned to return the light as defective I decided to first give the driver circuit a quick peak to see how it was put together.
The simple driver circuit consists of an Atmel AT89C2051 microprocessor running at 16Mhz, a ULN2803 Darlington array to drive the LEDs, a SN75176BP RS485 transceiver to talk DMX with, and a 7805 5-volt regulator for power. Apart from a few resistors and capacitors, that’s really about it.
I don’t know what I expected to find but I was a little surprised at how readily I was able to intuit the driver circuit’s construction. I guess at heart it still feels natural to consider myself an electronics n00b and the thought of pulling apart a finished product off the market and having an immediate intuition about how it works still feels a little unfamiliar.
Anyways, as I mentioned I had already decided to return the light as defective but I hadn’t really looked at its performance to determine if I wanted to actually replace it or just get a refund. I’m glad I stopped to consider this because when I put the COLORsplash Jr through its paces I was rather disappointed in the quality of light it put out.
Using the DIP switches on the back I configured the light to emit some secondary colors to see how well the colors mixed. The results were stunning tho not in a good way.
Note: None of the following pictures have been touched up or modified. They’re straight off the camera. Also, the camera tends to *understate* the poor color mixing. In real life the effects were far more dramatic.
| White |  |
| Purple |
 |
| Yellow |  |
So uh, yeah, I think I’ll be returning the Chauvet COLORsplash Jr. for a refund. Sheesh.
February 25th, 2008 at 12:44 am
this thing uses single color leds or multicolor? you see this same problem with a single lensed rgb led - because the 3 dies inside the led cant all be in the middle. but it seems surprisingly bad if they built this with single color leds. fixable with a dispersion lens in front of the leds, but i’m not sure if a lens exists that could mix the light and retain the spot beam.
February 25th, 2008 at 1:40 am
It uses single color LED’s.
Yeah, I was rather suprised the mixing was so terrible on it. You can *sorta* see it in the picture but the ‘Purple’ color simply looked like pinkish-red ring with a blue center in it. Yet when you look at how the LED’s are arranged, they’re evenly distributed. It’s not like there’s a higher concentration of blue LED’s in the center and red LED’s on the outer edge.
Junk.
July 5th, 2008 at 6:37 am
I have 4 of these, and on 1 of them more tham half of the green LED’s recently stopped working.
July 31st, 2008 at 12:58 am
Chauvet is another word for “complete crap that will break”. Avoid.