Electronics Projects Index

After transitioning to WordPress, I started writing up my newer projects as ‘blog posts’ rather than ‘pages’. Please find below a list of links to every electronics project related blog post:

• HDMI on the TRS-80 Color Computer 2

Coco-HDMI is an HDMI interposer for the TRS-80 Color Computer 2. It outputs a native HDMI stream from the Coco, without any analog video in the pipeline.



• Online RC2014 Emulator!

Online RC2014 emulator runs RomWBW, Small Computer Monitor, BASIC, or NostOS right from your web browser on emulated Z80 hardware.



• Teleram 4000 / T-4000 Vintage Computer with Magnetic Bubble Memory

The Teleram 4000 or t-4000 is a vintage computer that is portable and uses magnetic bubble memory. It runs the CP/M operating system.



• Speech Plus Prose 2000 Speech Synthesizer — original model used by Stephen Hawking?

The Speech Plus Prose 2000 is a speech synthesizer from 1982 based on the same algorithm as the DECtalk. This is the same brand/model of speech synthesizer originally used by the physicist Stephan Hawking. The Prose 2000 is a multibus card, but can be operated as a standalone speech synthesizer as well.



• Restoring a GRiD Compass and Building the World’s First GPIB Speech Synthesizer

I restored a GRiD Compass computer and created a GPIB-based speech synthesizer for it. The GRiD is unique due to its use of Magnetic Bubble Memory, and the Speech Synthesizer uses the vintage SP0256A-AL2, Votrax SC-01A, and SSI-263 ICs.



• NostOS: The Nostalgia Operating System, for RC2014

NostOS, the Nostalgia Operating System, is a new operating system for Z80/8080 computers such as the RC2014. It features a plethora of devices, run-time loadable extensions, and is designed to be inherently rommable.



• Sharp PC-5000, Vintage Laptop with Bubble Memory Cartridge System

Restoring a Sharp PC-5000, a unique vintage comptuer laptop with built in bubble memory cartridge drive. I talk about repairing the power supply, the keyboard, and the LCD screen.



• Monitor Cataract Repair on my Burroughs B21 Vintage Computer CRT

Repairing cataracts on the CRT tube of a vintage computer monitor.



• Burroughs B21 / Convergent AWS Vintage Computer Restoration

The Burroughs B21 Vintage Computer is a rebranded version of the Convergent Technologies AWS. In this post I obtained a B21 from eBay and work through the various steps needed to restore it and get it to work again.



• Scott’s 4-bit single board computer using the Intel 4004 or Intel 4040

Scott build a 4-bit single board computer using the Intel 4004 or Intel 4040 microprocessor. It features an 8-bit RC2014 bus, a multimodule socket, up to 8 RAM chips, onboard DC-DC converter, and either bit-bang serial or a UART.



• Magnetic Bubble Memory Mega-Post

Collection of magnetic bubble memory products and projects, featuring the 7110 magnetic bubble memory and it's supporting chipsets. Projects for multibus, HP 9000, RC2014, and others.



• Restoring a vintage Intel Prompt 80 8080 microcomputer trainer / development system

Vintage 8080 Prompt 80 Trainer has a multibus 80/10 board inside. I fixed the power supply, added the Forth programming language, and added a speech synthesis multimodule.



• Setting up an iRMX86 operating system on a multibus 86/30 vintage computer

I modify a System 310 microcomputer and install the iRMX-86 operating system on it. This is a multibus computer with an SBC 86/30 CPU board and a SBC-215 winchester controller and an SBX-218 floppy controller.



• Restoring a Teleram Portabubble/81 vintage bubble memory computer

The Teleram Portabubble is a vintage computer that includes magnetic bubble memory. It was designed as a wordprocessor for reporters and authors to use on the road and includes an acoustical modem.



• Vintage Industrial Multibus Computer Becomes a Nixie Tube Clock

Turn a vintage multibus computer into a Nixie Tube clock. Runs ISIS-II operating system. Has GPS and RTC timekeeping as well as speech synthsizers to speak the time.



• Designing a TMS5220 Speech Synthesizer Multimodule

Scott designs a TMS5220 speech synthesizer for his multibus computer. Lots of background on interfacing and programming the TMS5220 and the TMS65100 speech ROM.



• Multibus and the MDS-80 Series II with Homebuilt IO Controller using Raspberry Pi.

ISIS-II on a multibus SBC-80/24A vintage single board computer, with a raspberry pi secondary CPU to provide a disk interface.



• Ciro Mazzoni Baby Loop Ham Radio Antenna, an in-depth review

The Ciro Mazzoni Baby Loop is a Magnetic Loop Antenna that I use with my ham radio on 10 meter through 40 meter. In this post I do an in-depth review and analysis of the antenna.



• Can an AI program your Vintage Computer for you?

I used the Claude-3.5-Sonnet AI to write a program to play the song "Mary Had a Little Lamb" in fig-forth on a TM990 vintage computer together with an AY-3-8910 programmable sound generator.



• Adding bubble memory to an iPDS-100 Personal Development System / Cloning the iPDS-120 Multimodule Adapter

I build a clone of the iPDS-120 multimodule adapter so that I could add an iSBX-251 bubble memory board to my iPDS-100.



• Master Blaster: An 8008 Supercomputer.

I built an eight CPU 8008 computer that I called my "8008 Supercomputer". These 8 8008 microprocessors implement Conway's Game of Life, using a simple shared memory approach.



• Building a DIY Jupiter Ace Computer and Expansion Modules for it

I built a DIY Jupiter Ace FORTH Computer and designed modules for it that include a Speech Synthesizer, Raspberry Pi Supervisor, and a RAM expansion.



• Vintage Speech Synthesizers

A catalog of all my vintage speech synthesizer projects, reviews, and other resources. Lots of stuff on the Votrax SC-01 and the GI SP0256A-AL2.



• 80186 16-bit CPU runs MS-DOS on the Heathkit H8 Computer

An 80186 CPU board that turns a Heathkit H8 Vintage Computer into a powerful machine that can run some MS-DOS applications.



• Olivetti M20 Upgrades, Tips, Tricks, and New Boards

The Olivetti M20 is a vintage computer based on the Z8000 Z-8000 CPU. I show how to upgrade the memory, add a compactflash adapter, add a USB adapter, use the 8086 APB, program in forth, design a speech systhesizer, and play some zork.



• The Mini-08 8008 Single Board Computer

The mini-08 is a single board computer based on the Intel 8008 CPU, and 8-bit CPU from the early 1970s that launched the commercial 8-bit computer revolution.



• 8008 CPU Board for the Heathkit H8 Computer.

8008 CPU Board for the Heathkit H8 Computer. The H8 typically comes with an 8080 CPU board. I decided to go a few years earlier and build an 8008 CPU Board.



• FANUC PPR (Portable Punch Reader): Paper Tape on RC2014 and Heathkit H8

FANUC PPR Paper Tape Punch and Reader, repaired and modified to use with RC2014 and Heathkit H8 vintage comptuers.



• Single Board Bubble Basic Computer, and an RC2014 Bubble Board

Designing a single board computer that supports Bubble Memory, as well as an RC2014 Bubble Memory board.



• Controlling an AKI Teletypesetter Keyboard with a Raspberry Pi

Controlling an AKI Teletypesetter Paper Tape Punch from a Raspberry Pi microcontroller. Vintage punched paper tape project.



• Heathkit H8 Bubble Memory Board

Bubble Memory using the 7110AZ one megabit bubble memory device for the Heathkit H8 Computer, including the ability to read and write bubble memory as disks, and boot from bubble memory devices.



• 16 Megabytes of RAM in a Heathkit H8 Vintage Computer

Designing an 8 megabyte RAM board for the Heathkit H8 Vintage Computer, using memory paging to map the 8MB memory space into 64KB of CPU address space. Uses AS6C4008 RAM chips or 39SF040 flash chips. Includes Ramdisk driver for Heathkit HDOS.



• Designing a DRAM board for the Heathkit H8 Computer using the Intel D8203 DRAM controller

I develop my first DRAM project, a DRAM memory board for the Heathkit H8 computer, using the Intel D8203 DRAM controller IC.



• Blinkenlights for the Heathkit H8 Computer

Blinkenlights board for the Heathkit H8 computer, also a convenient place to connect logic analyzer probes to the H8.



• An 8085 CPU Board for the Heathkit H8 Computer

An 8085 CPU Board for the Heathkit H8 Computer, with Schematics, Gerbers, and Design information.



• No Vinculum? No problem a pi-based Vinculum emulator for my Heathkit H8 computer

Emulating a Vinculum VDIP1 IC using a raspberry pi, to communicate with a Heathkit H8 Computer.



• Speech Synthesizer for the Heathkit H8 Computer


• The Trump Card: Zilog Z8000 Coprocessor card for the IBM PC

The Trump Card is a Zilog Z8000 coprocessor/accelerator card for the IBM PC 5150 and clones, detailed by a Steve Ciarcia article in 1984



• Scott’s Zilog Z8000 CP/M-8000 Clover Computer

DIY Zilog Z8000 computer that runs CP/M-8000 with 1MB flash, 1MB RAM, and a couple serial ports.



• A new calibrator and a new amplifier for an old Drake

Drake R-4C crystal calibrator, sherwood-style amplifier, and other modifications



• Raspberry Pi Based DDS-VFO For Drake 4-Line Twins

A DDS-VFO digital synthesizer for Drake 4-Line Twins (T-4XC, R-4B, R-4C, etc). Powered by a raspberry pi. Uses alphanumeric display and rotary encoder.



• Adding a panadapter to a Drake R-4B Ham Radio Receiver


• Heathkit GC-1000 Most Accurate Enigma

Restoring, repairing, and improving the performance of a Heathkit GC-1000 Most Accurate Clock. This clock uses the WWV broadcast signal to automatically set the time.



• Tandy Color Computer Resources


• Sound and Speech boards for the Epson QX-10 CP/M Computer

Speech and Sound add-on cards for the Epson QX-10 CP/M Computer.



• An IDE Adapter for the Epson QX-10 CP/M Computer

A compactflash/ide adapter for the Epson QX-10 CP/M Computer system, uses a slightly patched version of the BIOS drivers for the Comrex Comfiler hard drive.



• Battery operated ESP8266 Wifi Button to trigger my sprinkler system

Use a battery-operated ESP8266 ESP-01 module as a wifi trigger for home automation.



• A basic and RAM board for HP-9000 series computers


• Assembling a thin client to serve as an HPDrive


• Raspberry Pi Floppy Controller Board

This floppy controller hat for the raspberry pi allows you to connect vintage floppy drives (360K, 720K, 1.2MB, 1.44MB, etc) to your raspberry pi model 4B.



• HP 27201A Speech Output Module, first speech synthesizer designed by a major computer manufacturer!

Teardown and reverse engineering of the HP 27201A speech output module, which uses the TMS5220 speech processor IC and was designed to be used with the HP 1000 and HP 3000 series minicomputers.



• The VTEK Small Talk Plus Epson HX-20, World First Laptop — Talking!


• This is Digitalker! … and Jameco JE520 too. Vintage Speech Synthesis.


• Cloning the ET-3404 6809 adapter for the Heathkit ET-3400


• Designing a Memory/IO (ETA-3400) addon for the ET-3400 Trainer


• Overclocking the pi4 with the Blink Blink ICE Tower CPU Cooling Fan


• Supercapacitor Uninterruptable Power Supply (UPS) for Raspberry Pi


• The Hayes Chronograph, a Remake for 2020


• Tandy 1000 Upgrades / PS2-Tandy Keyboard Adapter


• Restoring a Convergent Technologies NGEN PC/Workstation (Burroughs B25 / Unisys)


• Raspberry Pi Controlled DC Load


• Hot Shoe to 1/4-20 Quick Release Magnetic Mount for LumeCube


• Building a Power-over-Ethernet (PoE) Power supply using a DPS5005 module


• Scott’s FrankenNUC: 10Gbe Fiber Network on a 5th Generation Intel NUC 5i7RYH


• RAIN: Redundant Arrays of (In)expensive NUCs


• DIY Wireless Temp/Humid/Pressure sensors with Raspberry Pi Receiver, for monitoring stored 3D printer Filament


• Raspberry Pi 4: Do you need a fan? What’s the best fan for a raspberry pi 4?


• Vacuum Fluorescent Display (VFD) on a Prusa I3 Mk3 Printer


• The Nixie Tube Filadometer – A Nixie Tube Filament Meter for your 3D Printer


• COB LED Panels: 10 watt, 70 watt, and 200 watt.


• Resistive Load, Constant-Current Power Supplies, and a 3D Printed Desk Lamp


• 3D Printer OctoPrint Monitoring with Prometheus and Grafana


• Raspberry pi based indoor air quality monitor


• Building the ultimate USB power distribution system


• Making the e-paper equivalent of an Etch-a-Sketch


• Yet Another Masterplay Clone


• Atari 5200 Playstation 2 Dual-shock controller adapter


• Homemade Atari 5200 Analog Controller


• Scott’s Z80SBC: Z80 Single Board Computer


• Pi-Powered Atari 5200 Multi-ROM Cartridge (MultiCart)


• Raspberry Pi Virtual Floppy for ISA (PC XT/AT) Computers


• Converting a Seeburg 3WA Wallbox into a Remote for a Modern Music Player


• 8-bit ISA DiskOnChip / RTC board


• Measuring USB Power Cable Voltage Drop with my DC Load


• Leia’s LED Clock


• Building a Micro 8088 Single Board Computer


• 8-Bit ISA EMS Board / Flash Disk Board


• PS2-TTLSerial Adapter for RC2014 and MIDI


• Raspberry Pi Midi Hat / Building a Raspberry Pi Midi Jukebox


• Vintage MIDI: Roland MT-32, Roland SC-55, HardMPU, and an Xi 8088


• CTS256A-AL2 Text-To-Speech Board


• ISA Speech Synthesizer board using SP0256A-AL2


• Z80 Retrocomputing 18 – Z180 CPU Board for RC2014


• Z80 Retrocomputing 17: Enhanced Z80 CPU Board for RC2014


• Building an Xi 8088 PC


• Z80 Retrocomputing 16 – Unix on RC2014


• Z80 Retrocomputing 15 – CP/M on RC2014 Revisted, Using RomWBW


• Qume 842 8″ floppy drive with a RC2014 Z80 retrocomputer


• Building a Zeta V2 Single Board Computer


• Z80 Retrocomputing Part 14 – RC2014 Floppy Controller Boards