If the motor mount is hackable with reasonable effort, and the motor controller’s interfaces are open, then in principle… yes.

Yet in reality, companies build extremely complicated cars where premature failure of multiple components can successfully sabotage the whole. :(

I’ve once needed to repair a Mitsubishi EV motor controller. It took 2 days to dismantle. Schematics were far beyond my skill of reading electronics, and I build model planes as an everyday hobby, so I’ve seen electronics. Replacement of the high voltage comparator was impossible as nobody was selling it separately. The repair shop wanted to replace the entire motor controller (5000 €). Some guy from Sweden had figured out a fix: a 50 cent resistor. But installing it and putting things back was not fun at all. It wasn’t designed to be repaired.

Needless to say, replacing a headlight bulb on the same car requires removing the front plastic cover, starting from the wheel wells, undoing six bolts, taking out the front lantern, and then you can replace the bulb. I curse them. :P

But it drives. Hopefully long enough so I can get my own car built from scratch.

It sure is possible.

A typical “obscenely bright” LED chip might be Cree XML, but many similar chips exist. You’d need a plano-convex or equivalent Fresnel lens - shorter focal lengths favour compact design. Then you need a driver. Some are fixed while some adjustable with a tiny potentiometer. You’d need an 18650 cell holder (it can be made too, an 18650 will go into a leftover piece of 20 mm electrical cabling pipe with a spring-loaded metal cap engineered of something).

Myself, I bought a nice head lamp, but it broke after one year. The driver board failed. Being of the lazy variety, I replaced the board with a resistor to limit current and now it’s been working 3 years already. Not at peak luminosity, the resistor wasn’t optimal of course. :)

That is quite a lot of interesting experiments, thanks for introducing. :)

I’m inclined to add one more:

51: monitor the radio spectrum for drones (and if their signature looks hostile, warn people about them) - there’s a DIY recipe for a monitoring station out there somewhere, and some Ukrainian guys scan their sky using HackRF

SDR is definitely a technology worth learning. I’m already a happy user of RTL-SDR, but if I want to really see what my WiFi is doing, I should get a HackRF eventually too. (Note: WiFi is too fast to intercept without loss, except with another WiFi card, unless a slower bitrate is deliberately chosen.)

Trying to figure out how my heat pump supposedly supports WiFi… in unfathomable and non-standard ways. It’s available as an access point, I can associate and ping it, but no TCP ports listen and no UDP port responds. Nothing cool, undocumented features down to the rocky bottom. When you buy a heat pump and plan to automate its use, check out supported protocols before making a decision. :)

Unfortunately, yes.

I’ve had multipe experiences with seeing a flashlight battery which, according to labels, ought to have the capacity of an electric vehicle cell. And of course they don’t - on EBay or AliExpress, there’s a 100% chance that they’re just deceptively labeled. :)

If one needs high current, measuring the current with a known and low resistance (e.g. car headlight bulb) helps.

If the soil is dry enough to avoid liquefication, lifting should not happen. A ditch around the pool with drainage to lower ground at some distance would likely solve the problem even if the soil is problematic.

If the concrete is reinforced with rebar, it can withstand sideways load by the soil. If not, the issue of soil pressure would need closer consideration.

Disclaimer: I’m not an engineer