Few weeks ago we spotted on Hackaday the post about Open Theremin, on first look nothing challenging, just classic two HF oscillators with mixer which detects your body/hands proximity to the antennas and change the frequency.
Connected to Arduino and generating variable pitch and frequency tones.
The real gem was in one of the comments. The video how this guy is manufacturing the kits with do it yourself pick and place machine which he built from $50 ink jet printer mechanics.
Knowing how demanding to operate are the real professionl pick and place machines I know what amount of work is to build such thing from nothing, to program and debug it and to actually make it work something useful. This is months of efforts! The DIY P&P which actually works deserves our admirations!