mostly electronics
I have been a ham for a loooong time, and enjoyed communications both as a hobby and in the Signal Corps.
I've built a number of silly one-of-a-kind devices over the years.
One was a microprocessor repeater controller, with voice feedback.
Not so unusual today, but it certainly was when I did it. -
One of the more amusing, was an automatic garage door closer.
After installing the door mechanism, I'd come home and then leave the door open.
First design was to rely on the ambient light level; looking out the door and down the street, I could see the setting sun.
Revised design used CMOS parts, and was powered directly from the minimal juice that went to the remote "close" button.
It has a dip-switch settable timer, for 10, 20, 40, 80 minutes.
About ten years ago, I was experimenting with wi-fi, and seriously considered putting in a 3-mile direct link.
But, then I realized it was kinda pointless with all the other solutions available in suburbia (land line, cell phone, internet, fax, bicycle, carrier pigeon, etc), and moved on to satellite.
However, with a valid need, it'd sure be fun -
We need to set up some sort of extended WiFi network to connect my cabin and his to my satellite internet up here on the top of the bluff.