Glen's Stuff

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CONTENTS (Browser "back" button returns to this menu) :

Retro 8-bit computing
Pong central arcade
Test and measurement projects
Misc. projects
Analog computing experiments and projects
Boat anchor repair and restoration zone (a serviceman's log)
Design resources

Retro 8-bit computing

Tandy / RadioShack TRS-80 Model 1 clone

A fully-functional clone and improved ground-up hardware redesign of Tandy Corporation's famous home computer from 1977.
Realised entirely in current-production CMOS logic and using the Z80 microprocessor in its current guise - the Z84C.

Commodore PET-2001 clone

A fully-functional clone and improved ground-up hardware redesign of Commodore's first true personal/home computer.
Realised almost entirely in CMOS logic and using current-production versions of the 65xx-series CPU, PIA and VIA.

Pong central arcade

Oscilloscope Pong for one or two players

A paddle-and-ball game that renders simple vector graphics on an oscilloscope screen, but with a twist - the circuitry is implemented entirely in discrete components, all soldered together “dead bug” style over a sheet of bare copper laminate.

Over 300 individual semiconductor devices!

Video Pong for one or two players

A little bit of craziness – a video display version of Pong implemented entirely in discrete component circuitry, soldered together “dead bug” style over a rather large sheet of lacquered copper laminate.

Some features:

  • P.A.L. composite colour video signal generation
  • One (practice) and two player modes
  • 1.5 digit on-screen digital score counters (first player to 19 wins)
  • Realistic synthesised percussive ball-thwacking sounds
  • Simulated stereo sound with auto-panning that tracks the ball
  • 431 bipolar transistors, 6 junction field-effect transistors & 826 silicon diodes

Test and measurement projects

An ultra low noise measurement amplifier

A fixed gain, JFET-input amplifier for laboratory noise measurements.

Basic specifications:

  • An input-referred voltage noise of less than 300pV square-root-Hz
  • 60dB (x1000) gain
  • <0.1 Hz to > 1MHz bandwidth

A NAND gate-only frequency counter

A six-digit frequency counter with leading-zero suppression implemented entirely in NAND gate logic.

Complete I.C. complement:

  • 249 * 74HC00 quad NAND gate
  • 1 * 74HC132 quad NAND gate with schmitt-trigger inputs
  • 1 * 4011B quad NAND gate (used in analogue mode as the signal-input pre-amplifier)

A simple audio oscilloscope

An audio-bandwidth solid-state oscilloscope with a fully synchronised linear-sweep time base implemented with only six bipolar transistors and two silicon diodes!

Misc. projects

A prototype 2-inch C.R.T. composite video monitor

A prototype 2” C.R.T. composite video display monitor knocked up one rainy weekend.

Analog computing experiments and projects

GK-1 analog-hybrid computer system

A Fourier synthesis character generator

An alphanumeric display unit in which Fourier synthesis is used to construct the individual characters.

A three-dimensional projective unit

An analogue computing aid which maps objects defined in three dimensional Cartesian coordinates (x, y & z) to a two dimensional X-Y oscilloscope screen. The projection of the object is fully rotatable through 0-360 degrees on both the x and y axes of the object.

A magnetic deflection display unit

A Rössler attractor circuit

An electrical analogue of the famous Rössler attractor.

A hyperchaotic Rössler attractor circuit

An electrical analogue of the four-dimensional hyperchaotic Rössler attractor.

A Lorenz attractor circuit

An electrical analogue of the famous Lorenz attractor.

Sprott Systems Circuits

Electrical circuit analogues and oscilloscope display photos for chaotic Sprott Systems B through S.

A self-programming analog computer for chaotic Sprott systems

An analog computer designed and built to experimentally simulate chaotic Sprott Systems A through S.

Telefunken's bouncing ball in a box: an analog simulation

My implementation of Telefunken’s once famous analog computing demonstration problem.

Boat anchor repair and restoration zone (a serviceman's log)

Philips GM5650 oscilloscope repair

Design resources

My analog computing bookshelf

Books on this arcane art that I’ve collected, sourced mostly from on-line books sellers via Abebooks. If you have a passing interest in analog computing, here are some suggested titles to look for.

Coefficient tables for active filter design. High-pass, low-pass, 2-pole through 10-pole