Eric Thompson had a pretty crazy idea:
I’ve always had an idea to make a keyboard instrument that could be transposed. There are some harmoniums that do this by moving the action either left or right (one half step flat or sharp). I decided to achieve this by instead making the chromatic sounding parts moveable. Having a moveable/removable chromatic sounding piece has the added benefit of being able to swap in and out different devices to play on the same keyboard. For example, I have a set of saucer bells, a set of glockenspiel bars, a set of chromatic chimes; these could all be made into a plate that can be placed on top of the instrument and played with the same action rather than building a specific instrument for each of them.
Not only did he want to make an instrument that could shift to a different key without changing his hand position (or re-tuning a ton of strings), he also wanted to build this thing from scratch. He rounded up a bunch of parts, like the entire action of a piano, and got to work.
People often forget that the piano is really a percussion instrument. Each key press actuates a hammer that bangs on a key. To top this off, you can often find pianos on craigslist for free! Perfect for the aspiring musical instrument hacker. Eric is utilizing this assembly to bang on a bell tower instead of strings. The results are interesting to say the least.
The videos do a decent job of speaking for themselves, but Thompson has also put together a full album of images with tons of details on what he was thinking at the time, and how he overcame different obstacles.
When he’s not building interesting new instruments, he’s creating all kinds of other stuff (that ring box is awesome!). You should subscribe to his youtube channel to keep up to date on his latest builds.