The CST grant I received last year was used for three things: Iterating the Genera Brain project with a new circuitboard revision (rev3), working on the 2nd revision prototype of the Electrobass instrument, and working on the 2nd revision of the Vocodec vocal processor.
The Genera Brain project is an ARM-based microcontroller platform for embedded audio design. I started the project in 2017 to create a compact dedicated circuitboard that would allow the instrument created in my lab to produce their own synthesis, rather than using an external computer. This past year, I collaborated with Tom Erbe (of UC-San Deigo) to further develop the Genera Brain and the LEAF audio library, with the intention of bringing the platform to a wider audience as a research and teaching tool. Our plan is to improve the hardware and the audio library together, aiming to design audio firmware programming classes around the platform that we would teach in parallel at our own institutions, and ideally get the platform into the hands of other educators as an affordable, powerful, and relatively streamlined way to teach lower level firmware development for audio DSP. Last year, a grant from CST supported the development of this project, and Tom and I designed a 3rd revision of the Genera Brain circuitboard together, which now includes SDRAM external memory, a microSD card slot for removable storage, and a higher quality audio codec for a lower noise floor. We rewrote the LEAF library to account for issues that Tom had with the existing library, such as the lack of flexible memory management. Now the library has the ability to implement and support multiple memory pools, which allows for placement of code and variables more explicitly into optimized memory regions of embedded microcontrollers. Tom used the LEAF library and the Genera platform in his embedded audio course at UCSD in the Spring of 2020.
I also worked on revising my design of the Electrobass, an electronic instrument inspired by the bass guitar performance interface. The new prototype includes a new circuitboard designed to fit neatly inside the envelope of the instrument, with shielded circuit traces replacing ribbon cables for audio paths to reduce noise. I also created a new circuitboard for the fingerboard of the instrument, using a printed resistive carbon material to measure string contact position. The second revision is now in playable condition, but still has a lot of work to get it to respond reliably.
The Vocodec voice processor also got a revision update, although I had completed the circuit fabrication the previous year, I had yet to develop the firmware for it. Several students worked with me on the development of that code over the summer, and I was able to send prototypes to 9 musicians to test the instrument out. We intended to debut the new Vocodec in the PLOrk concert in April, but COVID-19 caused us to change our concert plans and that piece has been tabled for a future concert.
CST funding covered the expense of the prototype fabrication and assembly of all of those projects, which made these developments possible.
