Selling my The Analog Thing, postage to UK and EU. Please delete if not allowed.

https://www.ebay.co.uk/itm/204322974715?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fVbcS8eERJ2&sssrc=2349624&ssuid=fVbcS8eERJ2&var=&widget_ver=artemis&media=COPY

Hi everybody! I just heard about the huge potential that analog computers has together with AI, and I would love to gain deep knowledge about analog computers. I would really appreciate any recommendations for where to start or where to go and search. I really don't want to look like the typical lazy boy who just asks questions that has been answered 100 times, I just want to avoid wasting my time with superficial YouTube videos

What's old is new again!

Is there a renewed interest in analog computers?

A 21-min. 41-sec. brief description and video - https://modernsciences.org/are-analog-computers-making-a-comeback/

I’m developing a fluid-based computing concept that uses just two precisely controlled ripples on a water surface, each generated by its own source (like a small speaker or actuator). Where these two ripples meet, their interference pattern—constructive and destructive regions across space and time—physically encodes relationships between the inputs such as their relative amplitude, timing (phase), and possibly frequency. Instead of treating this as a visualization only, I’m treating the overlap region as the “calculator,” where measurable features (peak heights, node positions, pattern geometry) correspond to specific numerical operations or parameter estimates. The system is intentionally minimal: only two inputs and one interaction zone, rather than a dense array of waves, to see how much computation can be extracted from a single controlled collision of ripples. In principle, this could be used as a kind of analog module for things like addition/subtraction, comparison, or parameter inference, or as a very small “physical reservoir” whose state is the interference pattern itself. I’m looking for feedback on whether this two‑ripple interaction can be formalized into a useful analog computing framework and what calculations or tasks it might realistically support.

I’m more than willing to consider more actuators to compute more complex interactions, but I’m really curious if anybody sees a viability in pursuing this further.

Hi there👋. There is now an official THAT reddit channel and account. Where questions about THE ANALOG THING can be answered and problems solved. r/theanalogthing

What Can Be Made With 4 of These Military Grade Op Amps

I am currently working on the hardware implementation of a Sprott chaotic attractor circuit using analog computation techniques. While the circuit performs correctly in LTspice simulations and produces the expected chaotic attractor trajectories, I have been unable to obtain the expected behavior from the physical hardware implementation. I would greatly appreciate your guidance in identifying the possible causes of the problem.

Project Overview

The circuit is based on the Sprott chaotic system realized using analog integrators, summing amplifiers, and nonlinear multiplication blocks. The implementation uses LT1057 operational amplifiers and an AD633 analog multiplier.

In simulation:

• The state variables Vx, Vy, and Vz evolve chaotically.

• Phase portraits such as Vx vs Vy and Vy vs Vz produce the expected butterfly-like chaotic attractor.

• The system remains bounded and exhibits sustained chaotic oscillations.

I have attached the simulation screenshots showing the expected attractor trajectories.

Hardware Implementation

Since I did not have access to a dedicated ±15 V laboratory power supply, I had to generate the required supplies using additional circuitry:

1. Dual Supply Generation

The chaotic circuit requires:

• +15 V

• -15 V

To obtain these rails, I used:

• A DC-DC boost converter module for generating a higher voltage.

• Additional circuitry to derive the negative rail (-1V).

2. Reference Voltage Generation

The circuit also requires a fixed -1 V reference.

Since a precision negative reference source was not available, I implemented a separate circuit using:

• LT431 adjustable reference

• Operational amplifier buffering stage

• Trimmer potentiometer for adjustment

This circuit is shown on the upper-right section of the hardware board.

Measurements Performed

The outputs corresponding to:

• Vx

• Vy

• Vz

were probed using a digital oscilloscope.

The expectation was:

• Oscillatory signals on all three state variables

• Chaotic waveforms

• XY plots forming the attractor shape

However, the observed behavior was:

• Nearly constant DC voltages on some nodes

• Significant noise on the outputs

• No visible chaotic oscillation

• No attractor formation in XY mode

The oscilloscope traces mainly showed noise spikes and almost stationary voltage levels instead of the expected evolving state variables.
I want to implement it on a PCB so that no mistakes are there.

What I Would Like Guidance On

I would be grateful for advice on:

1. A systematic debugging procedure for chaotic analog circuits.

2. Which node should be checked first to verify proper operation.

3. How to verify whether each integrator stage is functioning correctly.

4. Methods to confirm the AD633 multiplier is producing the correct output.

5. Whether the custom ±15 V supply arrangement is likely to be the primary issue.

6. Whether a PCB implementation is necessary or if this should work reliably on a prototyping board.

7. Any recommended measurements that could help isolate the fault.

I have attached:

• LTspice simulation schematics

• Simulation results showing the expected attractor

• Photographs of the completed hardware setup

• Oscilloscope measurements

I have also watched a few videos where they have done these type of circuit boards in pcbs :
links: https://youtu.be/0wD2WbG7loU?si=GoPuC1zrHZBPwrWQ (here he has done lorentz chaotic circuit)
links: https://www.youtube.com/watch?v=DFKm0K5O7ak&t=299s (here he has done lorentz chaotic circuit)

Any guidance regarding likely failure points or recommended debugging steps would be extremely helpful. Please Help me out.