In 2017 I participated in the e-Textile Summer Camp at the Paillard Centre d’Art Contemporain & Résidence d’Artistes in Poncé sur le Loir, a small village 214 km from Paris. Rachel Freire insisted that I joined this panel discussion chaired by Dr. Becky Stewart:
"The History of Computing and Weaving, the Consumer Society and Data Democratisation"
with Becky Stewart, Audrey Briot, Rachel Freire and Adrian Freed
July 22 17:00- 18:00

I have researched the history of electronics, computing and e-textiles, but I thought I was likely going to be a "hair in the soup"–as the French say–as I don't have a portfolio of e-textile works that comes anywhere near the quality of that of my co-panelists. I reflexively took the role of respondent and prompted my copanelists into elaborating on their work and curiosities. I first noted that their work shows how we can rescue the worn out adjective "digital" by celebrating a continuity between the "digital" and "numerical" aspects of quipu (and it's ancient analogs) and contemporary e-textile projects - which very often involve interactions with our digits in gloves or interacting textile surfaces.

My second response was an improvisation on some philosophical work I had been doing on entrainment and entanglement. I am grateful to Hannah Perner Wilson, a key instigator in the Summer camps, for encouraging me write these ideas down. This note is a kind of writing where I am often told to "unpack" the ideas or integrate a line of argument. Thankfully Hannah found value in this writing without me addressing those concerns. She saw potential in it as part of a "zine" for woolpunkers, a pataphysical take on e-textiles inventors.

So, instead of unpacking the text, I illustrate it below in the style of a gloss.

Organized Entanglement

I propose the term "Organized Entanglement" to encompass fiber and textile art, design, engineering and science.

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.

Intro

I am studying how IC routing is done in large chips. I am following advice I often give people that it is helpful to learn how to do something by hand before using an automation tool. I was skeptical about this for chip routing because the scale of the problem these routers solve (trillions of gates) is outside what can be done by hand. As it turns out a few of the things I know about routing PCBs helped prepare me for learning some of the conceptual and strategic aspects of what these tools do.

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

Position is sensed by measuring the resistance of each ring of 16 conductive plastic strips around the bowl. The resistance is lowered as the draped conductive fabric shorts out more of a section of the strip. Pressure is sensed using the piezoresistive fabric strips around the annulus surrounding the bowl. Each piezoresistive strip sits on a segment of conductive fabric taped to the acrylic base. The resistance between this conductor and the ground potential is established by the conductive draped fabric in contact with the conductive gold tape at the top of the bowl.

The tablo senses position of the draped conductive fabric using the ring of conductive plastic strips on the bowl. Pressure is sensed using the piezoresistive fabric strips around the annulus surrounding the bowl.

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:

The fast touch algorithm reimplemented in the library available here was developed for my FingerPhone Instrument. The fast touch library senses touch on any digital I/O pin on many embedded controllers with the Arduino IDE. This includes Atmega 8-bit, SAMD21, and Teensy. This includes most pins on most micro-controllers. A few micro controllers have analog input pins that can't also do digital I/O . The library relies on the ability to enable a built-in pull-up resistor on the pin being sensed. Here is the algorithm:

set the pin to output a LOW value for 1uS or so.

set the pin to output a high via a built-in pullup resistor.

Read the pin regularly and evenly while it reads a low value.

The sensed value is reported as a function of the time it takes for the pull-up to bring the pin to a high value. This depends on whether the pin is touched.

The example code provided with the library uses the Arduino Tone library to sound pitches according to which pins are touched.

Notice that each call to the fast touch library implements a cycle of a relaxation oscillator.

I am indebted to Alice Giordani for exemplifying use of the library so well in this dreamcatcher:

When I saw Martin De Bie's Textilo e-textile 555 oscillator I wondered if it could be extended to allow for body interactions with the pads using CMOS 555 timers in the spirit of the CrackleBox.

I tested this CMOS 555 breadboard version.

This informed suggested improvements to Textilo to Martin who came up with a textile layout which we used to teach during the audio workshop of e-textile Spring Break: http://youtube.com/HdMsk6c3WGw

Alex blogged a great student perspective of this workshop.

I also brought along some PCB's which can be sewed to or pressed on Lego baseboards.

To address the need for more interaction room for the fingers I suggested to Martin to look at a radiating octagonal design. He prototyped this at the camp in copper:

Nicole Messier also picked up on this design pattern and made a 555 oscillator based FM Radio transmitter:

A walk through the schematic may be helpful.

We install a capacitor to ground (470pF) from pin 2.

Pin 6 is connected to Pin 2.

A 1Mohm pullup resistor is used on pin 4 (reset).

There is a decoupling capacitor for the speaker output (pin 3)

The diode (from battery to pin 8) is to help you not destroy the 555 timer if you install the battery backwards.

Now what makes things productively confusing is the absence of resistors in the story. These are provided by your fingers or additional LDRs or piezoresistive fabrics. The layout is designed to give you room to put fingers in the useful places for the two popular ways of making the 555 timer oscillator. One way creates square waves. The other makes controllable pulse waves. I capture these possibilities on the following schematic which has a special notation for where you add variable resistance: