I know, I am way late to the game on this one. But WTF. I made a Scanning Tunneling Microscope, in 2001, spent an entire year doing it. Coolest F-ing thing I ever did. No money. No reason other than my curiosity. I learned Sooooooooooo much doing it. I used to have a github on it but no one looked at it but, it was one of those things. It taught me something about patience, and a ton about so many things, controllers, ADC, DAC, DSP. It. was a fun lark. I have a PHD in EE from the 90's but I felt like I learned more from that project than anything else I have ever done. I know this is a post to the wind at this point. I don't care.