We've got RGB LED strips on the robot this year, for decoration and for the software to announce what its trying to do.

====== The LED strips ======

we had half a reel of this left over and unused from a previous season:
https://www.digikey.com/product-detail/en/sparkfun-electronics/COM-12021/1568-1153-ND/5673739 

These are "analog" RGB strips that have four wires:
  * common +12v 
  * negative for blue LEDs
  * negative for red LEDs
  * negative for green LEDs

To power them we hook up their common + terminal to +12v power, and then we need to connect zero, one, two, or three of the negative wires to -12v depending on what color we want.

What we like about these:
  * we had them around
  * they're cheap
not so good:
  * no protective coating on top of the LEDs
  * The "B" marking on the strip labels the green LEDs and the "G" marking is by the blue terminal.
  * Kind of fragile - easy to break the flexible circuit board when they're taped down to somthing (like a robot) and you yank them off.

====== The driver board ======

we found this COTS driver: https://www.amazon.com/gp/product/B01MRQFYJN

Its features:
  * four low-side mosfet switches (we only need three, one each Red, Green, and Blue)
  * screw terminals for power input and each of the four outputs
  * four RoboRIO-compatible three-pin headers for control input.  Each one has the customary -,+,Signal pins just like pwm and DIO cables.

====== Hookup to RoboRIO ======

We found COTS 3-pin female-to-female cables that fit and worked fine.  I think they may have come with the SPARK motor controllers.  If we hadn't found these, we would have made up cables.

They're hooked up as:

  * Red: DIO 7
  * Green: DIO 8
  * Blue: DIO 9

Each color turns on when the DIO is set to output and is outputting a "1".

====== Software ======

Amr, this one's for you.