History

There are few inaccurate histories of the 555 timer invention on the web so a good source is from the designer himself, e.g., http://semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzi...

He also wrote several interesting books. The history and detailed design considerations are covered in a book he kindly made available as a PDF file before his death in 2012: http://www.designinganalogchips.com/_count/designinganalogchips.pdf

Circuits

This is a reasonable compendium of interesting circuits using the IC: http://www.555-timer-circuits.com

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.

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.

I learned about this work as a teenager and managed to trace my fuzzy recollection while researching connections between textiles and electronics. It was published in Cybernetica Volume 2.

"I have recently completed building an electronic model of the 'growth net' principle and will now give a brief outline of its method of operation."

"What I described earlier as a common boundary now takes of the form of a moist fibre of cotton yarn connecting each input to the control grid of a pentode"

Here is a non-electronic relaxation oscillator:

Here follows my workflow to produce the publication list and bibliography on adrianfreed.com.

On Top of Musical Greeting Card (for better sound projection)

Description:

Rectangular grids are dominant forms in electronics and textiles. Triaxial grids have not been explored in e-textile work so this breadboard is offered to begin these explorations. Triaxial grids sample the plane with higher density and the availability of whug connections as well as warp and woof simplifies circuits by providing a natural power/ground/signal triple.

I like to build intrinsic sensors with fabric because they are more flexible and survive washing and environmental stresses better than extrinsic modules such as those in the Lilypad ecosystem.