This project was all kinds of wrong; over engineered and built on untested assumptions. It subsequently took stupidly longer that it ought to.
The plan was to finally do something with the R/C truck that my nephew let me have after a clear-out and the wireless camera I bought off eBay many years ago “because it was cool”. This is the circuit I cam up with:
The 100R resistors connected in parallel (resulting in a combined 33R resistance) together with the 2200uF capacitor would filter out power noise from the battery (the battery also powers the truck’s drive motor and servo) before it got to the (rather excellent) Pololu 9V Step-up/down voltage regulator that would provide power to the camera/transmitter unit. The LEDs being driven through the four resistors would provide light so the operator could see where they were driving when it was dark. So far, so reasonable.
Well, rather than doing some experiments and testing the my assumptions I just started to build. Bad idea.
For a start, I discovered that the 100R resistors limited the current enough that when the camera was powered there wasn’t enough current the light the LEDs. I solved this by removing the resistors from the circuit by bypassing them with a patch wire – problem solved; the camera and lights could both operate together.
Secondly, when testing the truck in the dark it became apparent that while the now working headlights looked very cool, they didn’t really provide any meaningful amount of illumination!
It turns out that the following circuit was really the one I should’ve built (but not before testing it, obviously!):
Not only is the circuit simpler, but rather than having to construct a board and drill-out/mount a box, I could’ve just soldered everything together, wrapped it all in insulation tape and fixed it to the truck with cable-ties: Job done.
Always remember: “If you haven’t tested it, it doesn’t work”
I’d hoped to embed a video of the view from the truck driving, but just as I’d finally go the thing working the receiver decided to go kaput. I’ve got another one on the way from China, so I hopefully I’ll be able to do that soon.