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2018_leds

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.

2018_leds.txt · Last modified: 2018/03/01 23:35 by tell