Light fades out?
 

This isn't specifically about the CMUcam, but about the green light.

We have ours made, and I connect it to a Radioshack Adaptaplug AC Adapter. It puts out 12vdc and 1 amp. When I connect it to the light, the light is bright for about 40 seconds and then starts to fade out. Eventually it gets so low that it might as well be off. If I disconnect the power wires and re-connect, it works fine again and the cycle repeats.

Any idea on what could be causing this?

EDIT: A quick multimeter check shows that my power supply is holding a constant voltage when not connected to the light.

Re: Light fades out?
 

This same exact thing happened to us, though it lasted a lot longer than 40 seconds, maybe 5 or ten minutes. We had an enclosed box, with holes but no fans, and when we opened the box, afraid we'd killed our transformers, it had just gotten warm enough that the adhesive label on the transformers was peeling off. We redid the box, increasing it's size and adding a big fan. The problem went away; in fact, I believe that we have run it for like 6 hours straight. We are using a 12 volt, 1.5 amp power supply.

Re: Light fades out?
 

At first I thought it was overheating as well. I just took off the cover and it still happened. The box is made out of steel and we have that small (1 inch diameter?) muffin fan mounted in it.

Re: Light fades out?
 

I don't know. We also took off the cover, and the same thing happened again, albeit to a lesser degree. If you could, try using the large (3"?) fans, sucking air out. Don't know. When we did this, it seemed to fix the problem.

Maybe they draw more current as they heat up?

Re: Light fades out?
 

I think that may be it... I remember a post comparing the amp pulled at cold and after X minutes. I'll search for it. Thanks for tipping me off :)

Re: Light fades out?
 

Yeah, somewhere, somebody said they used a 1 amp power supply, and it didn't cut it. Though they said that it ended up putting out 8 volts, dimming the lights, but not cutting them out. I'd definently try a bigger power supply. Maybe just rig a battery in to check for right now.

Re: Light fades out?
 

The piece of paper that came with each lights says that each transformer should be on a 2amp fuse. We are powering outs with a robot battery and 5amp fuse, and haven't had any problems with it. It doesn't drain the robot a lot, so one basically lasts all day.

Re: Light fades out?
 

Ive used a computer power source and have had no trouble either. I'm curious when they fade out is part of the tube being lit and not the other? Like light is only near the wires? Or is the whole thing dimming and turning off?

Re: Light fades out?
 

The whole thing is dimming.

I'm going to get a robot battery tomorrow, I'll post how it goes.

Re: Light fades out?
 

I thought the light box was closer to a 2.5 amp load. Your power supply is probably overheating and shutting down.

Re: Light fades out?
 

Have you tried useing the backup battery. The 7.2 volts it has is enough to have 4 completely on and 4 sort of on. Try that and see if it works.

Re: Light fades out?
 

That was me. We've since moved to hooking our light directly into a 12v robot battery, and that seems to work great. We really haven't left it powered on for more than a few minutes though, so I can't be of any help there.

Re: Light fades out?
 

We're using a 12VDC, 1.5A transformer and it seems to be alright. When connected, the voltage is ~11.2V, so the transformer is slightly overloaded, but probably alright. It gets a little warmer than I'd like, but again, it seems to be fine. I should also note that we are only using 7 lights. One of the supplied lights was bad.

As for a box, we didn't use one. I just put together a quick and dirty setup. I just duct taped the lights and inverters to the provided plastic sheet. It does get warm after a few minutes, so if it were in a box, I might be concerned about it.

Re: Light fades out?
 

I can't stress enough how useful a rigged computer power supply can be. I ran 7 converters off one of them with no trouble. Of coarse I also can't stress enough how important it is to do it safely (ie check that you have the right cable and you have a sufficient load). You can virtually (I wouldn't try the motors) test your entire electrical system on one. note I make no claim that doing this is not without risk and if you do do it I don't guarantee that you won't fry some electronics. I never have, but it can happen. Here's a thread on how to rig one http://www.chiefdelphi.com/forums/sh...ad.php?t=39754