Apopka Tournament Recap/Highlights

Shoutout to 3023 and 508 for blowing my eardrums out!

1 Like

I love the LEDs, and not just because they make your robot easier to spot in videos!

Haha thanks dude!

Im with @Aponthis here. Your LEDs are absolutely lovely! I am extremely curious as to how you managed to set that up. Those appear to be individually addressable LEDs similar to the Adafruit Neopixels. Individual addressable LEDs usually require a microcontroller to do some big banging or SPI or some such similar protocol to send data to each bulb.

As far as I’m aware, it is illegal to add additional MCUs to your robot. Did you do this through the cortex? If so please tell me how! Or, perhaps I’m incorrect and it is okay to have an additional MCU when used only for driving LEDs (a nonfunctional decoration).

Either way, I’d love to know. Thanks!

edit: Also, what port on the cotex did you power off of? Did you use PWM on a motor port or just the 3.3 IO voltage?

I don’t think microcontrollers are inherently illegal per se, just illegal if reasonably able to be (re)programmed with custom code. (Cameras typically have multiple microcontrollers yet are legal, for example)

As for controlling individually addressable LEDs, I would expect I2C or UART to be used.

Ah good point, perhaps they used one of those LED driver remotes, which would probably meet that definition. Can the op confirm?

Also, yes I agree. if they did do signal via the cortex and not an external controller, it would be over one of those buses, more likely UART. Although I’ve never heard of bit banging with I2C I suppose its possible if you want the headache of dealing with a complex protocol like that and clocking. I was more asking about the power rail for the LEDs: PWM based average voltage from the motor ports or fixed 3.3 IO voltage?

For instance, on my FRC team I ran some LEDs using a TI MCU over the SPI signal line and powered via the voltage regulator 5V 2A output. Too bad VEX doesn’t have a full electrical system because if it did cool LEDs would be way easier :wink:

We had the apa102c based LEDs from pololu.com last year. We powered them off of the Cortex and just used 2 digital ports for the power and interface pins. I guess I never metered the Cortex, but I think it’s 5v power on that rail, since the pneumatics use 5v valves as well.

Hello, I am the coach/mentor for #1533M and I helped them with the application of using the LED light strip. I can confirm that they are the Pololu APA102C LEDs and they are connected to the Cortex through two digital ports. They are programmed through some fairly simple bit banging in RobotC and the wiring couldn’t be much simpler for something like this. If anyone is interested in using these lights, I would recommend that they read the documentation on these lights and figure out how to make them work from there, it’s a fun, simple challenge that is a nice break from the usual work done for a competition.

1 Like

I didn’t realize that about the pnumeatics. Thanks for letting me know.

Thanks for confirmation. I might look into a strip like this because the timing constraints are much easier with real SPI. My current strip requires high speed bit banging (10 MHz) with no clock. Granted, it gives you some tolerance in high/low code lengths but its still very tight and I am not even sure if the cortex can hit those speeds reliably without sacrificing actual competition code :stuck_out_tongue: