LED Lights on Robot

The baseline is, I’m looking to add LED strips to our robot, just to add a bit of flair for showcasing at my school. Multiple questions at once! Please give advice as much as you can; any experience is welcome.

1- Which company and product of LED strips do you buy from?
2- How do you wire and program the lights?

Looking around, I see most people power the LEDs off the the 12V VRM in some fashion, but the LEDs I was looking at required 5 Amps, and the VRM provides only 0.5 A and 2 A. I’m looking for an RGB-W type strip, with color changing abilities. I’m just interested in what the larger community has used before.

About the programming aspect of things, I’m thinking of two ways to do this: 1) a button that goes through a list of preset colors on the robot controller, or 2) a series of levers that each control the RGB-W LEDs on the strip. No, I’m not talking controlling each LED, but rather one lever controlling red, another controlling green, a third controlling blue. I figured one might be able to do this by wiring red and common to a PWM and code it there, but PWM outputs only 5 V, which is not half enough for a 12 V strip.

Just looking for advice! Thanks!

Check out REV Robotics’ “Blinkin” LED Driver unit.
With this you can control LEDs with code or manually adjust with tuning knobs on the unit.
Here’s a video demonstrating the capabilities of the Blinkin.
I’m definitely considering using one of these next year, and I think it might simplify things for you by the way you’re describing you might do it.

4 Likes

Another tip is that LEDs can be plugged into 20A PDP ports with a breaker.

Be careful here, this isn’t quite correct.

You really want to give LEDs a stabilized voltage, otherwise they will dim when your battery voltage falls as you accelerate. You can also burn them out by giving them too much voltage when the battery isn’t under load or if motors get backdrived and turn into generators.

I also wouldn’t recommend plugging LEDs into the main VRM, even if they didn’t require too much current. First of all, the 12V/2A ports on the main VRM are reserved for the radio; you’re not allowed to plug anything else into them according to the rules. The other ports are legal, but if your LEDs should short it can burn the VRM fuse and kill your radio. You don’t want to sit dead for a match because of decorations on your robot.

I always recommend using a standalone buck-boost converter (like this one) plugged into a PDP branch circuit. They’re pretty cheap, you can have them next day from amazon, and they’re generally reliable. Most versions can also accept anywhere between 5-30V input, which is well over the range your battery will see during a match. And if you do manage to kill it mid-match, your robot should otherwise function normally instead of becoming a very expensive paperweight.

1 Like

You can connect MOSFETs to the RoboRIO DIO pins to modulate the color channels from the RIO. As for powering the LEDs, absolutely use a buck-boost regulator like AriMB said - my go to is this one.

The Blinkin LED Driver is a good device, would recommend, but it won’t be able to utilize one of the colors are on a RGB-W strip, since it has an extra contact for the white LEDs.

If you want more of a challenge another option would be to use 4 of these to control each color (since you want to use RGB-W strips) and an arduino or the roborio to provide the PWM signal.

If you use just an RGB strip you could just use the PicoBuck LED Driver, as well.

This is what we (3958) used for LED. Attached below is a document our former lead mentor put together on how to wire arduino onto the roborio.
led and roborio.pdf (1.4 MB)

We Program the colors we want, upload it to an Arduino Nano (knockoff) and then connect the LEDs to that. That all can connect to the 5v rail on the VRM

1 Like

For LED strips, we just grab whatever’s cheap on Amazon at the time (I’m convinced that all LED strips are made in the same factory and just rebranded, so honestly it doesn’t matter much).

For the controller, we’ve been very happy with the REV Blinkin LED Drivers on our robots the past few years. We’ve also had some luck using an Arduino to run an LED strip on our cart, though this takes a bit more work.

Also, RGB-W strips are overrated. They’re nice if you want to illuminate a space, but not optimal for most robot decorations, IMO (the “W” channel tends to wash out the colors). Standard RGB or Addressable RGB is the way to go.

We used these LEDs on our elevator carriage this year. We connected them to a 5V regulator that was wired into the PDP.

To control these individually addressable LEDs, we used a REV RIOduino which was connected to the MXP port on the RoboRIO. The code for that is here.

Our team used Neopixel strips which we bought off Adafruit, and they have well-documented setup instructions. We used an Arduino with an ethernet shield, which received data from the roborio, to control the LEDs. The code is pretty simple, can be found at https://github.com/the-null-terminator/MustangLEDs (with credit to 957 for sample code).

1 Like

Not to be too critical here or come off as condesending, but you guys realize there is no functional difference between that $99 roll of LEDs from Adafruit and a $20 roll (same length or longer) from Amazon, right? Like, they’re exactly the same, except one is 5x as expensive.

@Nate342