My boys are working on their pinewood derby cars, and they want to install LED lights on them. I don’t have any idea where to start to get them started on this. I ran by MicroCenter, and they have a strip of lights that you can cut to size, but I don’t know how they attach to a power source, or what that power source even is.
Please help me figure out what I don’t even know what to ask.
If you’re really wanting to DIY it, you might want to check out Adafruit. Lots of kits and things to create your own LED solutions. If you want something simpler, though, you can just order a string of fairy lights or similar from Amazon.
I don’t really know if there’s a walk-in store to buy electronic components, a la Radio Shack. That’s where I would go, in this situation, but I’d also know that I’m buying more than just the LEDs (battery holder, battery, current limiting resistors, switch) and then I’d be doing a bit of soldering and then carpentry to get everything into the car body. And I’d have to worry about weight limits.
I see via Google some vendors sell pre-assembled model car headlight illumination kits, which would at least save a fair bit of assembly work, but they still seem to require you to source at least the battery and its accoutrements.
Are they even permitted to have an on-board power source for Pinewood Derby? You just want to add lights, but someone will think of a motor, or electromagnet, or tractor beam…
It happened in the Big Wheels version aka Soap Box Derby: https://teacher.scholastic.com/products/westonwoods/study_guides/soap_box_derby_scandal.pdf
They also make generic Lego vehicle lighting kits that might work, like this one: All-Inclusive Vehicle Lighting Kit | Brickstuff Hobby Electronics
Or you can just buy one of those keychain LED lights that run off a coin battery, rip out the circuit board, and glue/solder the switch to the on position permanently.
Google’s bullshit generator thinks that it’s legal to put LED lights on a pinewood derby car but I couldn’t find an actual cite to back it up. The bullshit generator’s link for where it says they are allowed just goes to various kits and youtube videos explaining how to do it. There’s no link to any actual rules.
That said, there are many kits available online. They have both underglow kits and headlight/tail light kits.
This kit says that only one kit may be installed per car. It’s not clear if they are referencing any actual rule though.
Underglow kit from the same site:
I have no experience with either of these kits, and I am not familiar with current pinewood derby rules. I only include these links as representatives of many kits that are available online for those who lack the necessary electronic and soldering skills to roll their own.
Moderator Note
I have updated the thread title to more clearly indicate the topic.
Something like this just takes a cheap arduino, a few lines of code and some time:
Some strip LEDs with an integrated controller will be a lot easier though. It’s just a matter of getting 5v or 12v to it. The only thing then, if it’s even an issue, is that you’re limited (kinda) to having all those LEDs on a strip instead of putting them where you want them.
Poking around a little online, it looks like there are model rules for all BSA as a whole, but that each Council (roughly city-sized area) sets their own official rules, and are free to modify or discard the model rules as they see fit. So a full answer would depend on where the OP is. But from the examples of rules I found, I didn’t see anything prohibiting LEDs, and the most relevant point in the model rules is
Correction: I did find one set of rules that prohibits
I’m not sure precisely what electronics the race would use (likely some sort of light-gate timing device), or what would interfere with them, but presumably electronic lighting that does not interfere with them would be permitted. Again, check with your local council for details.
This may not be useful-
Are you sure you need LED’s? Electroluminescent paint might work. It is most commonly found in long, string-like tubes in Halloween maks. If you carefully remove the tube (it is a lot easier if you don’t care about saving the mask), you end up with a long, flexible light tube attached to a battery pack. The pack is generally already set to switch from off to on to flashing and back to off when you press the button.
Are you talking about EL wire? That would probably be the easiest, though it’s not very bright.
Probably. There is a blue circle of the stuff on the wooden box hanging from my belt
That’s EL Wire, same stuff I made this with:
I say this seriously and not sarcastically- That is really cool!
Thanks. It was a ton of work and probably 4 or 5 iterations to get there.
Here it is with the (room) lights on:
When my son was in cub scouts, 20 years ago, the local council had a Pinewood Derby category for show cars - display only and did not race. The year my son got to the District races, those display cars were really elaborate! Many would not fit on the track.
That’s a classic “exception that proves the rule” right there if I ever saw one. 
MicroCenter, which I mentioned, has a lot of components - but not the knowledgeable personnel of a Radio Shack.
My issue is that they won’t arrive in time. I really do need a solution that involves the components available at my brick and mortar.
I happened to browse Five Below tonight and saw a huge rack of keychains with all sorts of light and beeping blingwads. But one was a little car about the size of two fingers with headlights and made vroomvroom noises when you press the button. I’d imagine it would be pretty easy to reuse the guts for another car.