Light powering - voltages?

[neo]

First of all, we are wondering how other teams are powering their light boxes. We've tried computer PSUs, but either there isnt enough voltage or enough amperage (we have 3 lights. .7A x 12). We've tried running straight from a battery, but the voltage diminishes and the camera notices. I rigged up a second plug to one of last year's batteries and plugged it into a charger while the battery powered the lights. This just tops off the battery at ~13.6v.

Second question is, does anyone know what FIRST is powering their lights with? If they are using a 120v to 12v converter and letting those light have a constant 12v, would it make a difference if other teams are running their lights at 13-14v?

thanks.

[Robert Cawthon]

I am using a battery from last year and it seems to be doing ok. I have not noticed the camera complaining of the loss of light.

[mtaman02]

If your talking about the Green Lights that FIRST uses I have been using a 12v battery to power the lights. Chances are FIRST will use a 12v power supply to power the green lights.

[Daniel367]

Originally Posted by mtaman02

If your talking about the Green Lights that FIRST uses I have been using a 12v battery to power the lights. Chances are FIRST will use a 12v power supply to power the green lights.

if you find out what power supply they are using let us know. when I tested how much current the boxes were pulling (i was using two fans to cool it though i think the design only calls for one) i got a reading of 1.3 A at 12v DC. for just one box with 8 lights.

[mtaman02]

Did you check the Field Manuals on the Green Light Assy. They may have listed power source and such. As a matter of fact I'll go look that up now. Ok I just remembered that the Green Light is controlled by the arena controller and is powered from the same area as well so it is safe to say it has to be a 12vdc power source within the arena controller. The arena controller gets 120vac and then breaks it up for the competition controller, vision target, sensors and whatever the game is designed around. Boy does it pay off to be part of a field assy & dis-assy crew. Kinda remembered that from 2006. But then again the Target was above the station so maybe instead of having the wire come up through the rug they'll have a remote power source in the middle of the field. We'll I can't find anything in the field manuals as far as how it will be wired except that if a robot intereacts with the wiring the robot will be disabled / penalized or something like that. Which leads me to believe that the wiring may travel under the the rug and up the center of the rack and then terminate to each of the Targets.

[Cody Carey]

The power supply to any computer speaker set with a sub woofer (of the right voltage) should have exactly enough kick for you. They range anywhere from 700ma to < 1.5a depending on the size of your sub... So they will definately be able to power the cathodes. You don't even need to cut wires if you don't want to... using a little electrical tape I was able to hook the load (in my case not the KOP lights) up to the existing power jack on the cord with no risk of fire/failure.


As a side note: I was actually doing this to power a car amplifier/stereo system with 12" subs in my room. I used the power supply from a $40 pair of computer speakers to hook directly into the amp power in, and since those subs drew a heck-of-a-lot more current than the cathodes, I don't foresee any problem at all. I don't know if there is some difference which I am overlooking, but there shouldn't be.

[neo]

I tore apart one of the PSUs i spoke of before. there were some potentiometers inside labeled VR1 and VR2. VR2 happened to be the one that regulates the 12v output. got it up to 11.8v with the lights on, 11.7v without them on (weird). but it is close enough to 12v and is a constant voltage.

[neo]

got the question answered.

http://forums.usfirst.org/showthread.php?t=3289

a mentor tested a few of his power supplies and got one that was constant 12v 15a. with the lights on it drops .05v.