Summary

Demonstrating an unusual application of a CMOS NOR gate to implement a CMOS varactor controlled VCO, I explore the idea of circuit schematics as a music notation and how scholars and practitioners might create and analyze notations as part of the rich web of interactions that constitute current music practice.

Summary

I introduce a new synthesizable VCO using (n+1) mux2i cells from the SkyWater130 PDK to form a (2n+1) hybrid ring oscillator.

The FingerPhone in it's commercial manufacturable form

Door Bleeper, Freed, Adrian , Everyday Electronics, 10/1975, (1975)

This alternative to the 555 timer for making audio oscillators is built from simpler building blocks (inverters) and has more versatility. You can find the schematics that correspond to the build video here: https://www.youtube.com/watch?v=CzO_ZKMSnAU

In a recent workshop on e-textile sound for the 2018 e-Textile Spring Camp, I provided a unifying framework for analog and digital sound synthesis and capacitive sensing techniques under the rubric of relaxation oscillators.

The following pages provide context for the workshop and include links to contributions from my co-teacher, Martin De Bie. This includes pointers to various iterations of his 555 timer-based Textilo project.

This project will be expanded ongoingly with further relaxation oscillator schemes.

In the usual approach to PCB layout traces are laid out to connect signals and power to the pads of packaged parts and I/O connectors. This is a style that evolved for very high speed digital circuits. One usually also employs ground and/or power planes or a ground flood.

This style is not convenient for eTextile Appliqués which are most commonly single-sided and are based on cut traces rather than etched boards.

The entries in this table with an * were briefly reviewed in the 3 hour workshop the 2018 eTextile Spring camp. As the table shows, these are in the middle of the affordability/complexity/size axis and were selected for their potential in e-textile and wearable contexts. We had the good fortune to have Bela well represented in another workshop at the camp. Bela is transitioning to a new compact form factor which will make it easier to use with e-textiles.

Here is a non-electronic relaxation oscillator:

Not my first publication, but my first one with some challenging engineering. I did this in my late teens and it was published in a hobby electronics magazine, "Electronics Australia". https://adrianfreed.com/content/audio-oscillator-using-digital-ics

I discovered by accident that some folk from Greece published the same ideas in a professional technical journal in 1989 (attached). If you are a scholar of such things it is interesting to compare and contrast the modes of articulation in my vernacular engineering approach with those of the academic paper.