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 [2]
Alex blogged a great student perspective of this workshop [3].
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.
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 [4]. 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:
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 [6]
Some more:
http://www.nutsvolts.com/magazine/article/using-the-555-timer-ic-in-spec... [8]
https://hackaday.com/2011/02/25/hear-that-its-a-555-timer-am-radio/ [9]
AM transmitter
http://www.circuitsgallery.com/2013/08/555-AM-transmitter-circuit.html [10]
FM
http://streampowers.blogspot.com/2013/07/using-555-as-fm-transmitter-cir... [11]
High Performance VCO : http://www.electro-music.com/forum/topic-54623.html [12] DRAWDIO
https://www.adafruit.com/product/124 [13]
ATARI PUNK CONSOLE http://www.synthrotek.com/products/lo-fi-synthesizer-circuits/atari-punk... [14]
Here is the largest variant I know of: https://shop.evilmadscientist.com/productsmenu/tinykitlist/652-555kit [16]
and the smallest (a 1mm x 1mm) package:
http://www.ti.com/product/LMC555/samplebuy [17] https://www.mouser.com/Semiconductors/Integrated-Circuits-ICs/Clock-Time... [18]
Links:
[1] http://www.martindebie.com/research_project/textilo/
[2] http://youtube.com/HdMsk6c3WGw
[3] https://blog.hackster.io/sound-synthesis-with-arduino-etextile-spring-break-45d4cc87e31e
[4] http://www.555-timer-circuits.com/operating-modes.html
[5] http://semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Index.htm
[6] http://www.designinganalogchips.com/_count/designinganalogchips.pdf
[7] http://www.555-timer-circuits.com
[8] http://www.nutsvolts.com/magazine/article/using-the-555-timer-ic-in-special-or-unusual-circuits
[9] https://hackaday.com/2011/02/25/hear-that-its-a-555-timer-am-radio/
[10] http://www.circuitsgallery.com/2013/08/555-AM-transmitter-circuit.html
[11] http://streampowers.blogspot.com/2013/07/using-555-as-fm-transmitter-circuit.html
[12] http://www.electro-music.com/forum/topic-54623.html
[13] https://www.adafruit.com/product/124
[14] http://www.synthrotek.com/products/lo-fi-synthesizer-circuits/atari-punk-console/
[15] https://www.jameco.com/z/CSS555-ID-Custom-Silicon-Solutions-CSS555-Micropower-Timer-DIP-8_2146433.html
[16] https://shop.evilmadscientist.com/productsmenu/tinykitlist/652-555kit
[17] http://www.ti.com/product/LMC555/samplebuy
[18] https://www.mouser.com/Semiconductors/Integrated-Circuits-ICs/Clock-Timer-ICs/Timers-Support-Products/_/N-6j749?P=1z0yr2i