There is a big fan club for Kubota kb250 tractors on Facebook with people making custom mods and implements. I'm sure there are lots of similar things out there
This is the way in. Garden tractor enthusiasts, VW camper van enshusiasts, vintage motorcycle enthusiasts -- they all want to customize, and will spend to get it.
A trivial electronic gadget to turn an oil cooler pump on and off is a good start. Electronic assembly isn't noisy or stinky. At most you might need to bend sheet metal for a case.
Guitar players love audio processing gadgets they can turn on and off with their toes. Make something that can be adjusted to give them a unique sound. Distortion is easy to layer on.
A trivial electronic gadget to turn an oil cooler pump on and off is a good start. Electronic assembly isn't noisy or stinky. At most you might need to bend sheet metal for a case.
Guitar players love audio processing gadgets they can turn on and off with their toes. Make something that can be adjusted to give them a unique sound. Distortion is easy to layer on.