Back in 1966, a suitable toy for a geeky kid was a radio kit. You could find simple crystal radio sets or some more advanced ones. But some lucky kids got the Philips Electronic Engineer EE8 Kit ...
Making a servo tester using an Attiny85 micro chip, Attiny45 also works for this project. This diy servo tester is as good as any other servo tester, the difference is that it can be programmed to do ...