[Tutorial] How to make circular front and tail lights for your board

Today I will be showing you how to cheaply (less than 20$) make lights that should be compatible with around 90% of setups out there. They are basically LED ring lights that go around the king-pin of your RKP truck. Let’s begin!

Things you’ll need


(Click to expand for details)

Step down converter to 12V

This will convert your battery pack’s voltage down to 12V used for the LED lights. I use this one for 10s setups and lower.

LED ring lights

The outer diameter should be 40mm so that it doesn’t get in the way of the truck geometry, and inner diameter should be 10mm or larger so that it fits around the kingpin.

I used these white ones from amazon UK

And found identically sized red ones from Ebay.

Epoxy

Any will do I think.

Sheet metal

And scissors cutters to cut it

10mm metal drill bit

To cut the hole in the sheet metal

10mm washers

Probably stainless steel so that they don’t rust.

Wires and connectors

I used JST connectors, but XT-30 would also be a good choice.

Some kegs / metal clips

You know, what you use to keep pages together. You’ll see.

Fuses

Value depends on the strength of your step-down converter. Mine is 18W, which is around 2.3A, so a 5A fuse would be perfect.

Instructions

Step 1 – Measure and mark your cuts on the sheet metal

You want to mark the center point to drill, and a 40mm rectangle shape with the corners cut off that will attach to the lights.

Step 2 – Attempt to drill through the sheet metal

You want a HARD surface against the metal so that it doesn’t bend, but gets drilled instead. My fuckup basically made step 1 pointless.

Step 3 – Fix your shitty holes with a file

Step 4 – Retrace your cuts by just using the ring lights

Step 5 – Cut out a perfect circle

After that cut off a bit to make space for your lights’ wires

Step 6 – Flatten out your pieces

I used a tool meant for it, but you can just use a meat hammer or ask your mom to sit on it.

Step 7 – Glue the things

Mix up your epoxy equal parts or whatever’s written on the tube, apply it to the bottom of the ring lights, and then put your cut metal pieces on.

Then use metal clips to hold it down tight. To have the drilled hole be centered, I put the lights on my trucks, and adjusted it a bit until it looked right.

Step 8 – Let the epoxy harden

Step 9 – Solder connectors to the lights, and the converter box.

I used the pigtail approach to solder all the wires in parallel.

You might have to create an extension wire so that the front light reaches your box, wherever you put it in your board. The final thing should look like this:

I totally forgot to add fuses, which is very important because one of my converter boxes just exploded for no reason. You don’t want a short in your light wiring to kill your battery, so put in a fuse, god dammit!

Step 10 – assemble!

Take off the nut from your kingpin. Put on a washer. Put on the light. Put on another washer. Put on the nut. Tuck your wiring somehow so that it isn’t hanging loose.

Attach the step-down converter to your battery in parallel with your ESCs. It should be after your loop key or antispark. Enjoy!

Thanks for coming to my Ted talk.

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Ya got my thing hard. Thank you

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Countersink would be good for deburing the holes. Yeah, not everyone has the tools for that. And thx for the tutorial.:slight_smile:

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that img is a centre punch.:slight_smile:
they’re dirt cheap.

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I’ve hear it a million times, people calling a punch a counter sync. Maybe @Mainflow should cut @Mainflow a little slack :grin:

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Why do they call a punch countersink? I’m confused. They are completely different.:joy:

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it makes round holes, something not always common with drill bits…

spring-loaded center punch

now go do some good work

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It happens. People thinking out loud, trying to figure out how to do a thing. I was just joking, it read like 1 person was correcting another person. I had to go check, then I laughed :grin:.

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That’s the spirit of DIY. Use only the tools, who a person has in his drawer. And I know, when you are joking. A file is completely fine, but it takes longer to get the result. :slight_smile:

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See now I call them scratch awls.

Different strokes for different folks.

@rusins great implementation. It’s super low key and a quality writeup.

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Sweet lighting solution! If one wanted to cheat or didn’t have extra kingpin threads for more washers, couldn’t you just epoxy the ring light to the washer that’s already on the trucks, holding down the bushings?

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Yes – that was my original plan until my father asked why don’t I screw it on :sweat_smile:

Keep in mind though that the caliber hanger has a little lip there – this approach clears that lip, and doesn’t get in the way of the bushing :slight_smile:

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Nice :ok_hand: excellent lighting solution, nice and simple.

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savage :rofl:

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So you don’t have to do this right if you are only using 1 light (just front or just back)?
Amazing thread btw, you just gave me an amazing idea.
You need a serious tag :wink: and maybe add the price this takes to the thread so people actuall understand hoe damn cheap this is. Again this is just the best thing i have read in months… so simple yet amazingly effective

Edit, just another question to add on top of the first one.
In theory how many led lights that you got could you add to the same buck converter.
Like i am thinking just print and a adapter to fit on your baseplate & add 4 tail lights. Don’t ask why :smirk:

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This is an understatement around here

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This is awesome. But why cut sheet metal though? Wouldn’t using a large washer be easier?

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because it is more complicated. hence why we build because we love making things more complicated than they should be.
It is the end product that matters, not how you struggled your ass off when you could have gone to the hardware store for 20 cents. :grin:

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@Mikenopolis
If you can find a washer large enough, that would be amazing. It would cut down assembly time by half I think. Keep in mind you have to cut out a slit for the wires though.

@PixelatedPolyeurthan
Pigtails are just easier to work with if you have small wires. Do whatever suits you best.

240mA per ring light. With this 1.5A converter you could drive around 6 in total. It’s not too hard to find beefier step-down converters, so figure out how much you need by looking at the lights you choose, counting the LEDs, and multiplying by 20mA, if they’re the 1210 SMD kind. (Each of these ring lights has 12, and I measured around 240mA too, so it’s pretty accurate)

Edit: wait but the leds aren’t all in parallel, so you can’t just add up currents like that. I must have misremembered, I’ll make sure to measure in a few days.

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Can’t believe I missed this… this is the kind of documented DIY content I love to see.

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