A "Letters to Cleo" gem on YouTube. @kayhanley.bsky.social youtu.be/maSDo-ABgLI?...

Modular means I can add a breadboard to "Anna" if need be… This harmonograph program has not 2, but 4 pendulums! (2 pendulums for the X axis and 2 pendulums for the Y.) That's over 52 wires of code! (The longest program I have, um, written yet.) #analogcomputing #electronics

Happy Mother's Day, mom. Wish you were still here. 🥹

"Programmed" a simple harmonograph on the analog computer. One pendulum (displays red), a 2nd (yellow) and both mixed (green)—sometimes adding, sometimes subtracting. Switch to XY-oscilloscope mode for the Lissajous curve. (Next: double the program to 4 pendulums.) #analog_computer #electronics

(Little blurry…) "Anna" programmed for Lotka-Volterra (prey/predator) equation. 1st display mode: a strip chart with prey population red, predator orange. (Predator's population lags prey's.) 2nd display mode a kind of XY oscilloscope plotting pop. in "phase space". #analogcomputer #electronics

"Spring+Mass" is, I have heard, the "Hello World" of analog computing. "Anna's" pair of integrators connected in a circular arrangement give rise to oscillation. Pots control spring constant, dampening, mass… (ADCs & an ESP32 on "MAIN" give a visual representation.) #analogcomputing #electronics

I "programmed" (patched) Lunar Lander. A special "metering mode" on "Anna" reads analog voltages representing gravity, thrust, velocity, position—displays a small lunar module descending. (Breadboard is not for prototyping—it's how you program/wire-up the modules!) #analogcomputing #electronics

The final (1.0) boards/PCBs for my hobbyist analog computer (Anna) are finally rolling in from Asia. As I complete the manual, I'm playing with "programs" on it. I switch to "scope mode" and reset the integrators to display a "harmonigraph" simulation I wired up. #analogcomputing #electronics

Last for today: a scan of an ImageWriter printout of a screenshot of Glider 1.0.

Final "boss" in Glider: the cat that tried to obstruct your glider from escaping the house. An early sketch—the paw a separate bitmap could animate (the swat!). The cat "trick" was: move into pawRect & retreat quickly (swat misses). Then dive back in. (The cat waited a second or so between swats.)

Here's another early Glider sketch showing tables and candlesticks. For the tables, the bases were bitmaps, but the vertical support and table-top were rendered (allowing arbitrary heights/widths). The candle was a bitmap with a flickering bitmap flame. Just getting started here…

Very early Glider… Before I knew how to display an arbitrary PICT (picture, created with MacPaint, for example), I rendered icons instead (32 pixels by 32 pixels). Sketched on graph paper first… A very different glider on the left. The one on the right would win out (when I grew beyond 32 pixels).

Surprised I came across some sketches I did not know I had scanned/archived. This is an early Glider sketch when the paper airplane was the more common kind. It looks like electrical outlets might have given you "shots", not destroyed you. Ceiling ducts were bad too. I have a few more I can post.

I know, the timing is weird. Victor Franco ported my published sources for Glider 4.0 to the modern MacOS and, yes, we have another Glider game for the Mac. It's faithful to the original Glider 4.0 that came out in 1990. (And it's free.) apps.apple.com/us/app/glide...

Came across a book of nomograms & spent an hour recreating one (exported as SVG). Here it is. With just a ruler you can find the equivalent resistance for 2 resistors in parallel (see red dashed line as an example). Link (print it, try it): drive.google.com/file/d/1BeZ_... #electronics #nomogram

I re-made Glider some years back for MacOS/iOS. It broke at some point (perhaps an Apple change for Retina displays?) so I pulled it from the App Store. (Claude looked at the code—found some minor coordinate issues. Thanks!) Glider Classic for MacOS is back on. apps.apple.com/us/app/glide...

A friend who has been hand-making traditional medieval leather footwear for decades now wrote a book where he puts down his knowledge (for those wanting to learn): #sca #leatherworking #diy www.amazon.com/Process-Grid...

I wrote a free, browser-based Moon simulator game. You're welcome to play. (I don't recommend trying it on mobile.) mooncraft2000.com (More info on developing it: engineersneedart.com/mooncraft200...)

So happy to find that ‪Perry Bible Fellowship‬ is on bsky.

My hobbyist analog computer project coming along… The "strip chart" displays two voltages from the computer: an implementation of the Lotka–Volterra equation depicting prey population (red) & predator population (orange). (Red LED indicates overload.) #analogcomputing #analogcomputers #electronics

Any fans of John Foxx? Ultravox!?

hormuz.pythonic.ninja "I did that!" —Anon

Ron McAdams & I chatted about my Mac game Pararena—published by Casady & Greene around 1992 (youtu.be/QpK6fYYr-6o). Was reminded that Michael (Greene) was not pleased with my proposed splash screen. (I had to move the figure down.) (He would have really disliked what AI did to it.) #MARCHintosh

This analog computer project is perhaps my longest ongoing electronic's project. From perfboard prototype to PCB, the Adder module is iterated upon… #electronics #analogcomputing #diy

Laying out a PCB is something I really hate—hurts my head. I wrestle with trying to keep it "elegant". I was explaining to my wife that every time I add a via, an angel in heaven cries. #electronics #pcb #kicad #angelscrytooeasily

(Publicly) claiming my @mobygames.com profile: www.mobygames.com/person/39762... (They need me to do this to approve, feel free to ignore.)

When I began playing around with what would be the game, Pararena, I wrote a simple app to render a parabolic playfield. If a thing can be rendered with math, then math can also be used to simulate the physics of that surface (render players, a ball on it…) Screenshot I took (and later "painted").

A sketch I put together in 1992. Back then I would have drawn it as line-art first and scanned it. Once digital color was added in Studio-8 or an early Photoshop. (Too risqué for Casady & Greene to put on the box for Pararena, so they hired someone to come up with truly atrocious box art.)

I've been diving deep into analog computing—working on pieces of a kind of hobbyist-grade analog computer. (The way I like to learn a thing is to build a thing.) (If anyone is interested, I've begun documenting in this Google Group: groups.google.com/g/analog-com...) #analogcomputers #electronics

Someone created a site including many of the games submitted to Hacker News (aka HN, news.ycombinator.com/active). (Look for my Mooncraft2000 among the games.) hnarcade.com/games/catego...

I started an analog computer "google group" because the only other one I am aware of is on Facebook. Yeah, no shit. groups.google.com/g/analog-com... #analog #analogcomputers #analogcomputing

I look back at the 3D-printing that I did in 2025, what I learned: engineersneedart.com/blog/3dprint...

In 2025 I finally got serious about creating a scale model of an experimental NASA lifting body—from balsa. So I got close to finishing it on this iteration… #nasa #balsa #modelaircraft #liftingbody #alwaysbeiterating engineersneedart.com/blog/m2f3202...

Thinking about the year that is ending… I put together a small post about the balsa “2001: A Space Odyssey” model that I built in early 2025. I will probably try to do some write-ups of a few of the other projects I completed. engineersneedart.com/blog/orion20... #balsa

A power module for a breadboard analog computer. On left: prototype board, on right: 1st iteration from JLCPCB.

Analog computer project in progress. Breadboard first. Circuits that are okay move to prototype boards… Parts get harvested along the way. IC's are easy because they are socketed. (I can't be bothered to harvest sockets). Switches, large caps… (I have a bunch of crap resistors I'm happy to lose.)

Still prototyping analog computing modules. Moving stuff from breadboard to prototyping boards ("ElectroCookies"). (Red & blue "cookie" seen here.) An article from a 1970's hobbyist electronics magazine inspired the project. I've gone past that circuit now though. (Unsure where I'll land…)

Playing with analog computing (but digital metering, so sue me). Last night (after several hours of hair pulling) I learned that a 1% 10 kΩ resistor color bands is indistinguishable from a 1% 120Ω resistor—that is flipped around. Breadboarding is messy. Will make up a PCB for part of it soon.

I put together an electronics kit + book intended as a gentle introduction to transistors and early computer logic gates (resistor-transistor logic or RTL). I set up a Tindie store page for the little over a dozen I have readied. (I'll create a web site soon.) www.tindie.com/products/jca...

A second analog (integrator) channel breadboarded (top). Both channels are tapped and displayed on the ESP32 "software meter" in the center (showing two needles at once). The new channel uses dual op-amps instead of singles. I may make another analog channel and have a go with a quad op-amp.

From breadboard (left—wires can be bumped loose) to protoboard (right—wires soldered). One channel of an analog/digital hybrid computer experiment. An op-amp acts as an analog-computer integrator, 3 more op-amps scale, offset & invert the voltage so it is within 0.0-3.3V range for the ESP32 ADCs.

Each year the wife hand-carves a multi-color X-mas card. A destructive process: inking/printing a color before carving for the next color. This year I suggested she make just one print at each stage (in black ink) for me to scan digitally—print on the Risograph. Seems to be going well.

Dialing back to the 1990's and the first commercial Glider (4.0) game… Ward Hartenstein blew my mind when I downloaded his "Hands-Off House" from AOL. You don't touch the controls to play—the house itself takes care of moving the glider along. B&W version playthrough: youtu.be/nIzy_Fmjexs

Just having some fun at Pioneer's expense, I guess. #SpacetoberChallenge #sciart #spaceart #illustration

Sweep meter is better. (Here it is responding to potentiometer acting as a voltage divider.)

Working on an "analog" voltage meter for a project. (This slide-rule version will not make the cut.)

After all this iteration, I placed an order for (I hope) the final board. Finishing up the instruction manual as well. I should have the boards for sale on Tindie in November. They're a kind of "breadboard helper" for playing with (learning about) transistor logic circuits.

youtu.be/vyeeQAcho00 Looks like Gruez (sp?) has posted a nice Glider history.

Prototyping my first learning-electronics project kit is winding down (I am finishing up the manual as well). Top is through-hole, bottom my first go at surface-mount (I learned a few things and have changed it some). (Hard to find a domain name these days. Went with CircuitPixies.)

Another Riso experiment with Crimson, Sky Blue and Black inks. #riso #risograph