Touch Piano Hits All the Right Notes

We love a good musical build, and this one is no exception. For their ECE4760 final project, [Wendian Jiang], [Hanchen Jin], and [Lin Wang] of Cornell built the nicest-looking touch piano we’ve seen in a while. It has five 4051 multiplexers that take input from 37 capacitive touch keys fashioned from aluminium foil and copper tape. Thanks to good debounce code, the sounds are clean even though the keyboard is capable of four-note polyphony.

A PIC32 and a Charge Time Measurement Unit (CTMU) module generate a small, steady current that charges up the keys. The PIC scans the pins continuously waiting for touch input. When human capacitance is detected, the value is compared with the base capacitance using the ADC and the sound is generated with the Karplus-Strong algorithm.

The group’s original plans for the project included a TFT screen to show the notes on a staff as they are played. While that would have been awesome, there was just too much going on already to be able to accurately capture the notes as well as their duration. Check it out after the break.

18 thoughts on “Touch Piano Hits All the Right Notes

      1. Is that really necessary? Does it bother the Internet so badly? Why would you rather him misspell a word for the sake of proper pronounciation? Fur, Fur, Fur, Fur.

        Go Furk yourself.

        1. It’s not misspelling. German umlauts are ligatures of “a”/”o”/”u” and “e”. Just look at German handwriting from 80 years ago and you’ll realize how the “e” became two short strokes that eventually became two dots. In crossword puzzles you have to write all umlauts as two vocals.

    1. Not trying to bust your bubble but A) roll out keys have been around since 1986 and B) three guys got an EE credit in a 4000 level class for building what sixth graders do on the weekends at these hackerspaces. Perhaps go with the capsense banana keys next time?
      Wire out all 61 keys and hang them dead bug style with a pointed finger as the striker and you have a fun windchime with aftertouch no less lol or a “augmented reality mediadrome” as it would be on Kickstarter.

      Too much going on to display music notes? wtf?

      1. The point of a project like the one in the article is not to produce a new or groundbreaking device, but rather to demonstrate that the engineering student has mastered the theory to the point that he can apply it to a real-world project.

  1. For anyone commenting on the feel of the keyboard, while it wouldn’t have the same sort of feel as a traditional piano keyboard, and I wouldn’t use it for piano-style playing, these sorts of touch keyboards have their place. They often lend themselves quite well to synth playing; The light “action” makes them good for quick synth leads. However, this particular keyboard doesen’t have anything much in the way of expressiveness, which is one of the major advantages to a lot of touch keyboards; If he can, it’d be good to see him get poly aftertouch on this. Finger position sensing would be a nice next step beyond that, but it would require a major re-design of the system.

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