The Clavichord needs no introduction to fans of Early Music, and a lengthy one to literally everyone else. Even classical music buffs who have heard of Bach’s works for the “Well-Tempered Clavier” — another word for clavichord — will mostly have heard them performed on Piano. That is perhaps fitting, as the clavichord is a distant ancestor of the modern piano. It has keys — though fewer of them than a piano — whose action strikes strings — though much, much fewer of those than a piano, as each string is required to generate multiple notes. [Ian Summers] has an excellent guide on how he built his, though be warned that that link goes to a PDF and the SSL certificate was having problems as of this writing. If you aren’t comfortable grabbing a PDF over old-style HTTP, we’ve embedded the demo/build video below so you can give a listen to what this pre-piano instrument sounds like.

[Ian]’s Clavichord isn’t a pure reproduction of a historical example, which makes it unusual in the world of Early Music where most obsess over authenticity. That means [Ian] was able to document his design decisions and why he built the instrument the way he did. There are two octaves and ten strings, which means each string is expresses two or three notes since this instrument is fully chromatic– that means there are ‘dark’ keys for the sharps/flats. Like a piano, the keys whack the strings to make sound, but unlike a piano, they do so directly: no mechanism and no hammers, which makes for some interesting differences in the sound. You can add vibrato, for instance.

[Ian] accomplished this build entirely with traditional woodworking, unlike the 3D printed piano mechanism we saw recently. There’s enough meat in the guide, and the instrument is simple enough that we suspect it would be easy enough to adapt the design to make it with extruded plastic or laser-cut parts, like this Zither.

A piano’s internal mechanism for translating a key press into sound is surprisingly complicated. It has to do a lot of things simultaneously and quickly: provide precise control over velocity, ensure the hammer doesn’t press itself against the strings,  ensure the hammer rebounds without accidentally hitting the strings, allow for quick, continued strikes of the strings, and dampen the string after the key is released. Not only is that a mouthful to say, it’s a tall order for a mechanical device and took (arguably) around 150 years for the idea to be refined into what most of us would recognize as a piano. But could [dovetail] do it with a 3D printer in a few weeks?

[dovetail]’s design relies on compliant mechanisms, which are solid parts that flex in specific and controlled ways to provide movement. The action took many iterations to make sure that all of the feelings of all the parts of a real piano action were accounted for in this model. Pianos have more than one key, though, so [dovetail] also had to design a modular system to piece all the keys together. The modularity extends to the piano’s electronics as well, with a set of PCBs daisy-chained together, each of which supports a set of keys. This is a hybrid piano, a style with a real action but digital sound production. Using infrared sensors allows the instrument to behave as a MIDI keyboard, but one with the goal of feeling somewhere between a digital piano and a fully analog one.

The piano was first demonstrated at Open Sauce, where a number of musicians were able to try it out. As a prototype device it still has a few rough edges that [dovetail] plans to improve upon, like changing the sensors from IR to hall effect, improving the action and using a different filament. There are some other things he has planned as well which we look forward to seeing in future videos. And, although a completely different instrument, it has a number of similarities to this action built to strike a bass drum instead.

Thanks to [Keith] for the tip!

Most instruments, with maybe the exception of pianos, have consumable parts. Guitars need string changes, bows need rosin, saxophones need reeds. [Co:Creation Lab]’s balloon banjo requires both fishing line and a party balloon, lest it be semi-silent.

If you want to change the resonance, just increase or decrease the amount of air inside the balloon. Neither the balloon nor the strings need tools to adjust, but we might argue that tuning pegs are tools.

The balloon banjo was the result of a design constraint: a parent should be able to build it with their child. To that end, there are no metal screws, no recurring snap-fits in the assembly, and a single, internal, one-time-use snap fit for the adult’s tactile satisfaction. Instead, the balloon banjo uses 3D-printed screws. A six-year-old can turn them with their fingers, and it’s difficult to over-tighten them and strip the plastic threads.

Be sure to check it out in action after the break. If you would rather use extant plastic to make music, the Bottlephone 2.0 is calling.