Table of Contents
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.
