This is a placeholder post for the Joytone 2.0, I'm working on a full writeup, but wanted to get some pictures up for now.
The short version of the story is that around November of last year I was contacted by the Toronto International Film Festival. They have an annual exhibit called the DigiPlaySpace, which is an interactive technology exhibit for kids. The curator for this year's show had stumbled upon my website and asked if the Joytone could be shipped up to Toronto to be on display in this year's show.
The Joytone 1.0 was built for my senior design project at the University of Pennsylvania. It was my first real electronics project, and there were a number of time and cost constraints that led to a lot of quick and dirty design decisions. I told the curator that the Joytone 1.0 would break, but that I could build another one, even bigger and badder.
So I signed up for a membership at the Techshop in San Francisco and got to work. I taught myself how to layout PCBs, got custom circuit boards printed, bought a whole lot of LEDs, and took some woodworking classes. With the time and resources I always wanted to put into the Joytone, I was able to build a much more fully realized version of it. There's a lot of detail I plan to go into, but for now, here are some pics.
If you're a newcomer to the blog, a couple posts back there's a big ol' writeup on the thoughts and design goals behind the first Joytone, but I'll summarize them briefly here. I wanted to build a new electronic musical instrument, and I had two design goals. The first was to improve on the physical interface of musical instruments. Many acoustic musical instruments are designed around the physical phenomena that produce sound - a cello is larger than a violin because longer strings make lower notes, not because the larger form factor is advantageous for the player. The constraints of physics and a great deal of history have developed the physical interfaces we're familiar with today, and most electronic instruments seek to emulate their acoustic counterparts. Since electronic instruments aren't constrained by the mechanism of sound production, there's a really awesome opportunity to improve on the user experience of playing an instrument. The second design challenge I tackled was the expressiveness of electronic musical instruments. Many electronic instruments lack the same expressive depth as the acoustic instruments they're designed after, so I wanted to build an interface that would allow really rich, flexible control over the sound.
The Joytone's interface consists of a hexagonal layout of 72 joysticks, just like the ones you'd find on an Xbox 360 controller. The hexagonal arrangement of identical sensors creates an "isomorphic" layout. This has a distinct advantage over the non-isomorphic layouts of many musical instruments. As an example, a piano has white keys and black keys, which are different sizes and shapes. To play a C Major scale is very easy - simply play all the white keys in order from left to right. To play a C# Major scale requires using three of the black keys. Even though they're both Major scales (the same pattern of musical intervals), they're played in different ways. There are 12 Major scales, and each one requires memorizing a specific pattern of white and black keys - and that's not counting the various other flavors of musical scales. An isomorphic layout like the one on the Joytone removes all that bias. Once you know the pattern of jumps around the hexagonal grid required to play a major scale, that pattern is consistent no matter where you start from. The pattern for playing a C Major scale is the same as the pattern for a C# Major scale, they just start on different notes. Similarly, all major chords have the same shape, as do all minor chords.
The joysticks give the instrument huge expressive capability. I chose joysticks because they offer two dimensions of analog controls in a familiar and inviting physical interface. Each joystick controls one note. The vertical axis mixes between two different waveforms - a warm soft triangle wave, and a bright reverse sawtooth wave. The horizontal axis varies the tuning between a pair of oscillators - at one extreme they're exactly in tune, providing a narrow, flat sound, and at the other extreme the oscillators are out of sync by a couple hertz, producing a fat, wide sound. The distance the joystick has been moved from its resting position determines the volume of the note. With a really simple interaction, the player can control three distinct parameters. The Joytone can play six notes at once, and can control each of the three parameters separately for each note, allowing the player to emphasize specific notes in a chord, or use a rich palette of sounds all at once.
I'll post more details soon about the actual build process along with pictures of the whole journey!