I don’t know how niche they are, but a few I’ve done in the past
- 3D printed musical instruments. Print other designs or contribute your own
- lock picking. When you really get into it, you modify locks to make them more of a challenge and mail them to people
- Ham radio is hundreds of sub-hobbies in a trench coat. I’m currently mainly interested in linearizing switch-mode amplifiers, but was doing fox hunting for a bit (radio direction finding), and periodically do POTA (transmitting from parks)
HAM radio is whole range of things that were not possible when I was getting into it - first of all it's super cheap to start now, and you can probably bounce RF signals off the moon for less than $100 nowadays.
Shortwave radio has always allowed signals to go around the world (by bouncing off the stratosphere). Most likely the new digital + AI capabilities means that a few well positioned relays could make for a very independent, low bandwidth Internet.
Solar powered BTS or APs all kinds of experiments are possible...
Lock picking is great! Many security conferences will have a "lockpick village" where there are just a bunch of locks, lockpicks, and volunteers teaching people how to do it.
- 3D printed musical instruments. Print other designs or contribute your own
- lock picking. When you really get into it, you modify locks to make them more of a challenge and mail them to people
- Ham radio is hundreds of sub-hobbies in a trench coat. I’m currently mainly interested in linearizing switch-mode amplifiers, but was doing fox hunting for a bit (radio direction finding), and periodically do POTA (transmitting from parks)