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TSU Meeting MONDAY — October 6, 2025

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David, Adam, Alger Salt, Carl Miles, Rick Roland, Mike, Mark, Keith, Brian, Chris, Ryan

At Adam's suggestion, the October 6 meeting was themed around robotics on Timex/Sinclair hardware. David walked through a draft blog post pulling together period sources: Bruce Taylor's ZX81-based "Henry" robot (built around a 16K RAM pack plus a Byte-Back 16K, with the Computer Continuum RX81 interface board), the Hobby Robot "Rabbit" and "Oscar" (both, as it turned out, built largely from Home Depot flower pots), the CATS newsletter science-fair writeups on a robotic arm and an I/O interface, the Mattel Big Trak, and the obnoxiously expensive Lennox "complete robot teaching system." The group also covered the RB5X, Topo, Heathkit Hero, Androbot, and Armatron, with Keith demoing his Armatron and Mike pulling out the relay board from his own Henry-style robot.

Two guests anchored the conversation. Alger Salt, joining for the first time, described the VOTEM — an analog interface he and a coworker built and sold for the ZX81 in the early 1980s, based on an Analog Devices AD531 voltage-to-frequency converter feeding the cassette input, with a Schmitt-trigger cleanup stage and a transistor-junction temperature probe (linear 0–100 °C). Several hundred were sold; one went up on the Columbia shuttle as part of a UCLA/Stanford hollow-ball-bearing experiment and ended up logging cargo-bay temperature. Rick Roland (smallrobot.com / norlandrobotics.com), who has been collecting robots since the 1980s, talked through the Topo lineage, the RB5X aftermarket (he has a semi-trailer of RB5X shells and supplies parts), the educational "Sam" robot he built for TI calculators for ~20 years, and his ongoing effort to preserve documentation as older collectors pass on. Rick wants to build a Henry but has never been able to find an RX81 interface — David pointed him at Tim's reverse-engineered RX81 PCB (orderable from JLCPCB), which the group agreed Tim should publish on GitHub.

Carl Miles gave a hardware update on the enhanced TS1000 ("1068") board he is building in collaboration with Ingo (who is doing a full-size keyboard case). The new revision is a full motherboard replacement rather than an expansion: it integrates a programmable joystick port, an AY sound chip (the "Zon-X"-style add-on), 512 KB of RAM, and the ZX-Wespi ESP32-based VGA/Wi-Fi video sniffer. He has also finished the design for a companion expansion board that brings most of those same features (minus Wespi, since the 1000 expansion bus carries no video) to an unmodified TS1000. Carl has just finished populating the built version shown on camera — desoldering parts from the show prototype with a heat plate onto the new black PCB — and expects to power it up and report results at the next meeting.

The meeting wrapped with a wide-ranging tangent through computing history: Sinclair's trick of using half-bad RAM chips in the 16K Spectrum (the same trick the TRS-80 Color Computer used), the Jupiter Ace (Mark held up two), Husband Forth being based on Tree Systems' Plura Forth, the Ada language, and Excalibur's "Savvy" (an Albuquerque AI-ish language demoed at the same 1984 Albuquerque robot expo where Henry won an award). The next meeting is Sunday October 19; planned topics are more robot show-and-tell, the ZX Spectrum Next (including a member's interest in building a TS2068 core for it), and a follow-up from Carl on whether the new board boots.

Highlights

  • Alger Salt joined for the first time and described the VOTEM analog interface (AD531 V-to-F into the ZX81 cassette port); one shipped on the Columbia shuttle logging cargo-bay temperature.
  • Rick Roland (smallrobot.com) joined — robot collector with a trailer of RB5X shells; wants to build Bruce Taylor's Henry but has never found an RX81 interface board.
  • Tim (NZ) has reverse-engineered the Computer Continuum RX81 robot interface and has a PCB orderable from JLCPCB; group agreed it should go up on his GitHub.
  • Carl demoed the freshly populated build of his enhanced TS1000 ("1068") motherboard — joystick port, AY sound, 512 KB RAM, ZX-Wespi VGA — with a companion expansion board now designed for unmodified TS1000s.
  • Next meeting Sunday Oct 19: more robot show-and-tell, ZX Spectrum Next discussion (incl. a member's idea of a TS2068 core for it), and first power-on results for Carl's new board.

Projects discussed: "1068" — Enhanced TS1000 · ZX-Wespi / Wespi-Nano · TS1510 Cartridge Interface Clone · TS-Pico Topics: Hardware projects & new boards · TS1000 / ZX81 / TS1500 · Video upgrades (composite, RGB, HDMI) · Pico / modern interfaces (UnoDos, etc.) · ZX Spectrum · User group meetings & events

Summary generated from the meeting recording; the full transcript is kept in the group's private archive.