Solenoid 12v output for LED's?
 

Our team has 2 sets of LED strips (one red and one blue) that we would like to light up depending on what team we are on. The downside of these lights is that they are made for a 12v power source and not for a 5V, so would it be illegal or ill-advised to take the lights and wire them directly into one of the outputs on the solenoid breakout board and be able to trigger them by turning a solenoid on or off in code?

EDIT:
for those of you who want more information on them here it is
http://www.led-lighting-manufacturer...-strip-40.html

Re: Solenoid 12v output for LED's?
 

This seems pretty clear...

But you can hook them up to a spike and control that with pwm.

Re: Solenoid 12v output for LED's?
 

ok....so that idea is a no go.
Are spike relays the only allowed relays on the bot or could we wire in out own 5V relays such that the switchable power on one side is from the PDB, and the output goes to the LED's, and the coil hooked up to a relay on the digital sidecar so that when we enabled the relay on the digital sidecar it triggered the relay and passed the 12v through to the LED's

Re: Solenoid 12v output for LED's?
 

You can make your LEDs operate on any voltage you like, you are not limited to 5 volts.

The way to do this is to determine the voltage and current required to operate. A Red LED needs about 1.8 volts, a blue needs about 3.1 (but these can vary somewhat), and a typical LED wants to see about 20 mA. If you are working with a single LED, you calculate how many volts a "dropping resistor" must drop to feed the LED the right voltage. For example, for 20 volts on a red LED at 20 mA, you need to drop 18.2 volts. R=V/I so 18.2/0.020=9120 Ohms, anything around that value should be fine.

For a 5 volt LED strip, the manufacturer has already installed a resistor. Find out the current requirement for the strip (from the vendor, or by measuring it). If you want to run it on 12 volts from the robot (which is really about 12.6 volts) you need to drop 7.6 volts. R=V/I again, V=7.6, I is the current, that'll tell you the resistor value you'll need, get one close to that.

One important consideration, particularly for LED arrays, is the power rating of the resistor. Too small a rating and the resistor overheats (you can guess the result). Watt's law is P=I*V, if the resistor drops 7.6 volts at, say, 100 milliAmps, you have 0.76 Watts: A 1/4 watt resistor will overheat in seconds, a 1/2 watt in minutes. You MUST use at least a 1 watt resistor!

Always be sure to check the power as well as the resistance you need!

Re: Solenoid 12v output for LED's?
 

the LED strip that was purchased is supposed to be run at 12 volts. The use for the strip where we bought it was to be put in cars for lighting effects and we want to put one on our robot and i was wondering if its against the rules to use power from the power distribution board and a relay output from the digital sidecar to light these up using a "hobby" style relay rated for 5v switching.

Re: Solenoid 12v output for LED's?
 

Again, The Manual is your friend.
Based on this question and your original, I respectfully recommend that you read the &*$*@@ thing!
(emphasis mine)

Re: Solenoid 12v output for LED's?
 

The wording in the rules is prohibits any relay modules other than spikes.

But because it is a decoration it's not really part of the control circuit. I would say it's legal for that purpose but I'm not the GDC and I'm not the guy who's going to be inspecting your robot.

Why don't you just make it easy on yourself and your inspector and use a spike.

Re: Solenoid 12v output for LED's?
 

we would use a spike but were a rookie team and we've already used one of our spikes on the compressor and we have plans for the second one as well.

Re: Solenoid 12v output for LED's?
 

I bet you could find a veteran team in your area who would be happy to give you one.

Re: Solenoid 12v output for LED's?
 

Ben,
This rule applies to your dilemma if you do not wish to turn them on when enabled...

<R51> Decorations may draw power from the 12 Vdc electrical system as long as they are powered via a dedicated 20 amp circuit breaker on the Power Distribution Board, and do not affect the operation of other control system components.

However, you must also satisfy this rule if they are bright or cause a distraction...

<R02> ROBOT parts shall not be made from hazardous materials, be unsafe, or cause an unsafe condition. Items specifically PROHIBITED from use on the ROBOT include (but are not limited to):
A. Shields, curtains, or any other devices or materials designed or used to obstruct or limit the vision of any DRIVERS and/or COACHES and/or interfere with their ability to safely control their ROBOT
B. Speakers, sirens, air horns, or other audio devices that generate sound at a level sufficient to be a distraction or hindrance affecting the outcome of a MATCH
C. Any devices or decorations specifically intended to jam or interfere with the remote sensing capabilities of another robot,including vision systems, acoustic range finders, sonars, infra-red proximity detectors, etc.(e.g. including imagery on your robot that, to a reasonably astute observer, mimics the VISION TARGET)