Watercolor and analog electronic study of a Lesser Angle-winged Katydid, 2018. I plugged in a couple of crickets to give this fellow some natural context. To read more about how I made this, visit my project “Hacking Nature’s Musicians” : https://hackaday.io/project/161443-hacking-natures-musicians
electricity
Follow me on Hackaday /
I have started a project to describe and share my analog electronic circuits designs so that people can better understand my electronic practice. My project, located on Hackaday.io, is called “Hacking Nature’s Musicians.” You can find it here: https://hackaday.io/project/161443-hacking-natures-musicians
In a recent project log, I describe how I create chirping crickets using discrete transistors. Check it out: https://hackaday.io/project/161443-hacking-natures-musicians/log/153312-crickets-natures-favorite-astable-multivibrator
Owl surgery /
Paper owl looking onto its electronic eye circuit, 2018
Transitions. Sometimes it feels like the holes that we have are equally -if not more- beautiful than what promises to fill them. Here, a paper owl contemplates the circuit that I designed to fit into its eyes. The addition of electronics to a static object adds more than functionality and aesthetics - it changes the identity of the object. Non-electronic things live in a physical world with thousands of years of creative history, while electronic things are very new. What was once an owl then become a robot - perhaps more robot than owl in our estimation. Does the owl stand to lose more than it gains?
Machine-centric intelligence /
We struggle to relate to machines on their own terms, despite the fact that we created them. I suppose there are people with fluency in some machines, but the body of knowledge in computer science alone vastly exceeds anyone's capacity to understand. Moreover, there are subtle and often surprising effects that arise from even basic electronic components - instruments for manipulating electricity in ways that have yet to be discovered.
However, if you add human features like the eyes in this video, suddenly we connect. But with what do we relate, really, besides our own reflection? We must push ourselves beyond human-centricity to see things for what they really are.
Shift registers /
I am in the process of building a control system for the insects in my latest Electrolier. As a starting point, I will use shift registers with (or possibly without) linear feedback. Adding linear feedback involves "tapping" two or more of the logical outputs, evaluating their state with boolean logic (usually an XOR gate), and feeding the result back into the start of the shifting sequence. In my video, you can see two 8-bit shift registers in the center (TI part number CD54/74AC164E). I put LEDs on the logic outputs Q0-Q7 to visualize what is happening. As you can see, the LEDs of the two shift registers are not synchronized, a property of an undefined starting state that I will exploit to get randomness for "free" -- at least that's what I'm thinking.
More about my breadboard: on the right is a 555 timer in astable mode which provides a clock pulse of about 1x per second. On the left is a 5 volt regulator - this part is irrelevant if you have the correct DC supply voltage, but mine is 12 VDC.
Good general overview to answer the question “what is a linear feedback shift register” (LFSR):
https://zipcpu.com/dsp/2017/11/11/lfsr-example.html
On choosing taps for a linear feedback shift register:
https://cs.stackexchange.com/questions/1121/choosing-taps-for-linear-feedback-shift-register
Mini project on how to implement a LFSR: https://www.slideshare.net/KishoreChandrahasVanam/lfsr
Another helpful paper on using an 8-bit LFSR (i.e. Texas Instruments chip CD54/74AC164):
https://pdfs.semanticscholar.org/320a/8b2e781ac6165b400eca96047489685fd1f7.pdf
One final note: because shift registers are comprised of flip flops, an option to add true randomness to this otherwise pseudorandom bit generator is to exploit the metastability characteristics of a flip-flop as described here by @crj11: https://electronics.stackexchange.com/questions/394557/old-school-pseudorandom-pulse-generator-requesting-assistance-with-hardware-des?noredirect=1#comment965703_394557
August insects /
Landscape painting and analog electronic soundscape (detail of work in-progress). August 2018
I create the sound of a buzzy August insect using a 555 timer to drive a transistor astable multivibrator (to give timbre). Another slow astable multivibrator provides pulse input to a 555 timer in monostable configuration, that gives a pulse out to the base resistor of an astable multivibrator that sets the tempo. That's why the insect rattles for awhile and then stops (monostable 555 goes high - the rattle tempo is active low).
Prototyping Night Insects /
Here I am at my bench prototyping various analog electronic insects for my latest "electrolier" sculpture. The sounds are made using a combination of astable multivibrators (oscillators), some of which create the audio timber and others establish a chirp-like tempo. The speakers are custom piezo electric devices that I have physically modified to achieve different sound qualities, such as brighter versus muffled and close versus distant. Individuality is achieved by subtle variations in the electrical signal and the output device.
Piezo speaker housing /
Here's a prototype of a housing for a piezo speaker that I will actuate with analog electronic insect sounds. The shape of the housing and mechanical pressure on the piezo element will change the pitch as well as the volume. I made this housing by first laser cutting 1/4" acrylic and gluing the stacked rings to make a pyramidal-shaped buck — see images below. Note that there's a central hole all the way through the buck to aid the vacuum forming process. I’ve vacuum-formed .080” and .090" acrylic sheet over the buck (both work fine) and used a laser to cut the shapes out. My registration needs improvement, but you get the idea. The piezo element is mounted inside of the housing by a short length of plastic tube that I glued in place.
Below I show my process to cast the acrylic buck in plaster (using an alginate mold). I will use plaster, wood, or metal bucks in the future because acrylic deforms in the vacuum forming process. In either case, it is critical to use mold release.
Why am I doing this? Because when RadioShack went out of business, I could no longer buy the piezo speakers that I used for my insect sounds. I was forced to reverse engineer the part --which turned out to be a blessing because the sound of insects is heavily dependent upon the mechanics of speaker design (not just the electronics which drive the speaker). For a previous blog entry on this issue, link here or read about my project “Hacking Nature’s Musicians” on Hackaday.io