[FTC]: Functioning LEDs?

Now I know in FRC its becoming somewhat common to have leds that serve a function but in FTC what would you do with LEDs that served a side function besides looking good and how would go about it?

Nothing in the Game Manuals this year that we we can find say that you cant use the LEDs for a fuctional use.

Now ways of going about it, there are different ways, three of which are below.

1. Prototype Board

2. Motor Port.
The Motor Port idea is something that my team used in the GET OVER IT challenge a few years back. We used an LED tower that we made in the center of the robot to tell us if we had a magnetic baton. Since we could control all 5 of our batons one by one, as it moved closer to the release point, the leds would strobe faster and faster, until it was the baton about to go out, then it was a solid red. We did this all by connecting the wires into one extra motor port we had, and had that “motor” run in the background. That year we went all the way to the WORLD Championships, and past inspection and everything with it.

3. Its own circut.
Last year we had our claw set up with some conductive metal, with rubberbands in the bottom, and if a weighted ring sat on it, it had enough pressure to push it down, which would then complete the circut. All it was was a 9-volt battery velcroed to the back of the claw, wire that ran to the metal(Which was the “switch”), then to the led. And Boom, light! An orange and purple LED for either the back ring or front ring in the claw.

Please note that, although an official forum posting would clarify this for sure, I don’t believe that options 2 and 3 are legal, at least this year. I believe all functional LEDs must be powered by the prototype board.

Yes, getting a offical saying on this would be the best. But Looking at the manual again just now, we found this.

**<R08.s>**Visible light LEDs with their connected electronic circuits are allowed. Power for the LEDs may be provided by the main robot battery pack (TETRIX or MATRIX) or by no more than one (1) battery of any type not to exceed 9 volts. LEDs used as visual cues must be controlled via connections to a HiTechnic SuperPro Prototype Board or the NXT Prototype Board.

So in one thing it says that it can be powered by the robot battery OR a 9 volt, and then below, the “functioning” leds.

So yes, it seems like this year, the Option 2 and 3 I listed would be “out of code,” for this year.

As I understand it - you can power LEDs from the battery and control them from the prototype board.

See post #59 here:

On our robot, we soldered a special circuit board that the Prototype board plugs into, and we have some MOSFETs and other circuitry on it, to control lights, and other functional sensors. Power is coming from the main robot battery. The LEDs we used were RGB led strips, non-addressable, and we use them to display our alliance color during a match.

We have functioning LEDs this year. A writeup of how we accomplished this is here:


The lights will pulse teal (our team color before and after the match,
purely decorative). During the match they indicate the direction the
drivetrain is pointing (it’s reversible). The NXT is also keeping a
match timer and they will start flashing yellow at the beginning of
the end game and flashing red with 10 seconds left. I thought the
timer might be inaccurate, but it’s surprisingly correct.

There’s various stuff we do in autonomous, mostly for debugging
as well.

THANK YOU SO MUCH! I’ve been wanting to do this for some time, but never figured out how to do it. Is there a wiring diagram/parts list?

After the season is over I’ll see about teaching our electronics lead how to use Eagle and put up a schematic.

Parts are simply an ATmega328 burned with an Arduino bootloader, the Hitechnic Protoboard, an addressable LED strip (available from Adafruit or Sparkfun), a 5v voltage regulation circuit built around a LM7805 with heatsink, a couple of small breadboards, and miscellaneous hookup wire.