Adrian Freed

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.

This header file provides extensions to the iostream << operator so you can pretty print C++ containers. It has a few interesting examples of template metaprogramming and uses some of the more modern C++ (2017) features. The repo code is evolving: https://github.com/adrianfreed/containerostream

This is the first of a set of thematic overviews of CNMATs work I am writing that cover the period since our inception to the closing in 2017 of the research sector after David Wessel’s death. The activities themselves are more completely understood with concurrent perspectives of many themes so this serialization is more a reflection of the cursed sequentiality of language than any suggestion that a particular theme might be more important than an other. Future themes may include Spatial Audio, Musical Programming Tools, Musical control Structuring, Instrument Building, etc.

Last week the world of wearables lost the light of one our shining stars, Valérie Lamontagne.

I invite you to celebrate her life by reading, citing and responding in your own way to one of her major life’s works: her 2017 dissertation: “Performative Wearables: Bodies, Fashion, and Technology”.

You can find it here: https://spectrum.library.concordia.ca/982473/

She covers some examples used in her dissertation here: https://vimeo.com/196041125

Valérie’s dissertation contributes to the field of wearables by carefully and clearly looking at our field with a combination of two powerful lenses: performativity and non-human agency. Performativity is a well-established lens articulated by Austin for speech acts, made popular by its use for gender by Judith Butler, for power by Jean-François Lyotard, and Karen Barad for cultural and feminist studies of science. Explorations of non-human agency have taken on a recent urgency from the extinction and climate crises. Both these lenses have a long, interesting, convoluted intellectual history so I especially appreciate Valérie’s approach of using extensive case studies of applications familiar to us as a “soft” way into learning the conceptual underpinnings.

What might you be able to do with the deeper understanding that comes from reading this work? It can give you a grasp on the thorny problem of cultural uptake- which designs will have lasting impact? Why do we see the same designs (tropes) being recycled in the field, e.g., cellphone/music player controlling backpacks? It can deepen understanding and appreciation of recent exploratory work in the field. For example, Hannah Perner-Wilson, has been exploring and celebrating the humble pin. She has moved from from pin as a tool, to pin as a material and in her recent whimsical work to pin as an active agent with its own agendas.

I was using performativity, non-human agency and related lenses in my studies of the history of electronic musical instruments while I was in the same program as Valérie at Concordia (INDI). As I surveyed images of the labs. where these musical instruments were created in the last 100 years, I saw one piece of apparatus “photobombing” every picture: the oscilloscope. I no longer see this as a prop or minor tool of the trade. As a non-neutral visualizer of certain sounds it has huge agency over what these electronic musical instruments did. It delayed the adoption of “noisy” and “chaotic” sounds because they don’t visualize well on the traditional oscilloscope. And so it is with the battery of wearable technology. The battery’s promise to deliver power is underwritten by our promise to recharge them. This agency of entrainment has induced “range anxiety” ever since the wearables of the nineteenth century to modern electric vehicles.

As Melissa Coleman and Troy Nachtigall just pointed out, Valérie Lamontagne, did not have a chance to expand and broadly diffuse the fruits of her Ph. D. labor. Dissertation work can easily get lost in libraries and obscure university web sites because it isn’t indexed as well as conference/journal/book publications. It has only 4 citations in scholar.google.com as I write this.

Even as we struggle with our shock and sorrow, let’s read and share her deep and valuable work.

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.

My best π day was in 1975 when I invented a new way to estimate π using elementary geometry and algebra. This wasn’t a particularly important result for the mathematical world because there were already so many ways to estimate π but it was one of those moments I can see now as watershed that strongly shaped the rest of my life.

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.

There is an older style of PCB layout that is more suitable for low-speed e-textiles that I remember seeing with old transistor radios. The style is almost all copper with just a few lines etched away to separate conductors.

This makes designs more robust with multiple parts soldered on and removed and with multiple sewing points at the edges.

It also makes for less weeding and more surface area that will be fused/glued to the base fabric.

It was also common for many of the traces in these radios to be curved.

For the eTextile Spring Break I guided Martin De Bie through some iterations of his original Textilo design that includes this new thinking on layout and a further insight regarding the 8-pin DIP packages commonly used now by eTextile electronics experiments (with the ATTINY and 555 timer being common choices). This insight is to start the design from the DIP package and imagine the negative space of the smallest amount of conductive fabric that needs to be weeded to separate the 8 pins and combine the constraint of roughly equal area given to the conductors attached to each pin. This results in a motif with 8 radial lines and 8 triangles between them.

Here is the original textilo with its elegant pads to sew to:

Here is the next version with more conductive material to work with alongside the prototype of a radial design. The radial design includes serpentine interdigitation to allow for touch interaction:

Nicole Yi Messier picked up on this radial design pattern for her wearable 555 timer based FM radio transmitter: