For the homework 2 of PCOM, I designed a glove, or rings, to simulate like a piano, just like the belows:

In the very beginning, I designed all the staffs with multiple elements, like 555-chips, LCR circuits, buttons with force and so on. 

When I designed all the staffs and decided to make the prototype, I estimated the price of that prototype, find it almostly like 100 dollars in total….

I’m not so rich, so I just went to the supermarket, buy a brass-paper, and do all staffs with scissor, Arduino and lead. The circuit map is just as below shows.

Since the finges can be binary, instead of making sound by one finger, we can make multi-fingers as input source, which make it possible to generate 2^4 – 1= 15 kind of tones with four fingers. Just as the melody below: