On this robot, the team decided to try adding some LED strips to the robot. Our idea was to use them for decoration, and possibly robot software status, and driver assistance.
Design
We used our digikey voucher for these:
https://www.digikey.com/product-detail/en/sparkfun-electronics/COM-12021/1568-1153-ND/5673739
These strips are flexible circuit boards, containing multiple LED (Light Emitting Diode) components about an inch apart. Each package contains red, green, and blue LED chips. The ends of the strip have four terminals:
common anode (+ terminals) red cathodes (-) green cathodes (-) blue cathodes (-)
To light these up, one first connects the positive side of a 12v power supply to the common anode terminal. Then, to light it up green, connect the terminal for green to the - side of the 12v power. Lighting up combinations of red, green, and blue together result in 7 different colors.
To control these from the roborio, we tried to use this chip and board:
https://www.sparkfun.com/products/14451 http://www.sparkfun.com/datasheets/Robotics/TB6612FNG.pdf
Although it says its meant to drive 2 motors, it drives both sides of each motor, so it actually has *four* drive circuits that can be used almost independently. We used one each for red, green, and blue (and one spare).
Connections are:
TB6612 vcc: +5v TB6612 PWM : +5v TB6612 standby: +5v TB6612 AIN1: red control input TB6612 AOUT1: red LED drive output TB6612 AIN2: green control input TB6612 AOUT2: green LED drive output TB6612 BIN1: blue control input TB6612 BOUT1: blue LED drive output
We wired up the sparkfun board onto a larger piece of proto-board, and included a scrap of the LED strip, so that we can test things without hooking up all of the LED strips on the robot.
Control inputs come from the roborio, or another source of a 5-volt control signal. We wire these with the white wires of three cut-down “PWM” cables.
+ 5 volts to run the control logic in the TB6612 comes from the red wire of one of the PWM cables.
+12v to power the LEDs comes into the little assembly on its own terminal strip. we wire this to a 5A breaker on the power distribution panel (PDP).
Debug
The LED strips never worked on the robot, although the individual strips and the controller tested fine before installation. There were reports of smoke.
We'd like to try debugging these after the fact, to see what we might learn.