How do we turn a LED ring light on and off?

This kinda spans Electrical and Programming (LabView), so I thought I’d post it here after finding nothing conclusive anywhere else via searching. We’re trying to run a green LED ring light for vision tracking, but we’re not sure where and how to plug it in to allow our robot code to turn it on and off at will. Any advice is greatly appreciated!

Power it with a Spike Relay.
http://wpilib.screenstepslive.com/s/4485/m/13809/l/599706-on-off-control-of-motors-and-other-mechanisms-relays

If you need to buy one:

Is there any way that doesn’t require an additional purchase?

5v or 12v led?

If 12v, then you can use the Pneumatics Control Module, and control it like a solenoid. You can also power an LED off a motor controller (full on/full off).

If 5v, then, depending upon current draw, you might be able to use the Relay or DIO ports. You can also power a 5v using the PCM or Motor Controller if you use a properly sized resistor to reduce the voltage to the LED.

Yep, should’ve specified 12v. I’m a programmer, not an electrician. :stuck_out_tongue:

So we’ll run it off the PCM then. Thank you!

PCM has max current limit for Solenoid output of 500 mA, be mindful of ths

http://ctr-electronics.com/PCM%20User’s%20Guide.pdf

As somebody who is not an electrician, I will ask our electrical team if that will still work.

Sorry with VRM you will not be able to turn it off, my bad. Spike, motor controller or custom circuits are your best options.

If you just don’t want a blinding light in the pits while you’re trying to test code, you could hook up a switch to the LEDs so they can easily be turned off. Of course this wouldn’t be what you’re looking for if you want to control it via code. For that situation, a relay seems like the best bet.

We’ll be trying the PCM idea today. Do we just fire it like a normal solenoid? Or do we only need to use the on/off functions?

If this doesn’t work we’ll order a relay. Thanks for your help!

You would just treat it like a solenoid. Activate it for on and deactivate it for off.

q: How many programmers does it take to change a light bulb?
a: None. It is a hardware problem.

q: How many electricians does it take to change a light bulb?
a: None. They think it is a software problem.

This is too true in the context of our team.

Either way, PCM works like a charm. Thanks!

That’s great. Can you tell me how many LEDs are there on the ring? Each LED typically takes about 15mA and a smaller ring shouldn’t have issue with 500mA limit on PCM (I was concerned in my earlier post).