From the perspective of a later decade it’s sometimes quaint and amusing to look back at the technological objects of desire from times past. In the 1980s for example a handheld television was the pinnacle of achievement, in a decade during which the Walkman had edged out the transistor radio as the pocket gadget of choice it seemed that visual entertainment would surely follow. Multiple manufacturers joined the range of pocket TVs on offer, and Sony’s take on the format used a flattened CRT with an angled phosphor screen viewed from behind through its glass envelope. [Niklas Fauth] took one of these Sony Watchman devices and replaced its TV circuit board with one that turned it into a vector display. The Sony Scopeman was born!
The schematic is deceptively simple, with an ESP32 receiving audio via Bluetooth and driving the deflection coils through a pair of op-amps and a set of driver transistors. These circuits are tricky to get right though, and in this he acknowledged his inspiration. Meanwhile the software has two selectable functions: a fairly traditional X-Y vector ‘scope display and a Lorenz attractor algorithm. And of course, it can also display a vector version of our Wrencher logo.
We like the Scopeman, in fact we like it a lot. There may be some discomfort for the retro tech purist in that it relies on butchering a vintage Watchman for its operation, but we’d temper that with the observation that the demise of analogue broadcast TV has rendered a Watchman useless, and also with the prospect that a dead one could be used for a conversion project.
[Niklas] has had more than one project appear on these pages, a memorable example being his PCB Tesla coil.
In the time before smartphones for on-the-go visual entertainment, there were portable TVs. You might think of a portable TV as a luggable device, but the really cool ones were pocket-sized. Perhaps if you are familiar with pocket TVs you’ll be thinking of a Citizen or a Casio with a matchbox-sized LCD, but before those devices reached the market there was an earlier generation that featured tiny CRTs. These were simply the coolest electronics that an ’80s kid could lust after, and [Nick Reynolds] is lucky enough to have one. It’s a Sony Watchman from some time in the first half of that decade, and because it’s useless in the age of digital broadcasts he’s upgraded it by installing a Raspberry Pi in its case.
The unlikely inspiration for the project came from the 1970s British sci-fi TV series Space 1999, in which portable CRT-based communicators were a prop. They were typical of the sci-fi vision of the future in shows of the period, one that got so much right but didn’t quite see the smartphone coming.
The Watchman features Sony’s angled CRT, and fitting a Pi Zero W into the limited space behind it called for some careful insulation of its parts with Kapton tape. He’s even included a Pi camera module with a contorted run of flexible cable, placing it beneath the screen where a tuning indicator once sat. He has no sound as yet, but is able to demonstrate a working videophone using Ekiga as a client. He has a few more Watchmen, and has plans for a suite of retro videophones, and a Pi 3 based model.
Surprisingly this isn’t the only Sony Watchman that’s had this kind of treatment, previously we’ve brought you one that hosted a Pong game.
As an adventure in computer history, [Len] built up a clock. The Z80 Micro TV Clock brings together a homebrew computer and three Micro TVs into a rather large timepiece.
The computer powering the clock runs the CP/M operating system. This OS was eventually released as open source software, and a variety of homebrew computer projects have implemented it. This clock is based on an existing breadboard CP/M machine, which includes schematics and software.
With an OS running, [Len] got a text editor and C compiler working. Now custom software could be written for the device. Software was written to interact with a Maxim DS12885 Real Time Clock, which keeps the time, and to output the time to the display controllers.
The Micro TVs in this build are Sony Watchman displays featuring a 2″ CRT. The devices had no video input port, so [Len] ripped them open and started poking around. The NTSC signal was found by probing the board and looking for the right waveform.
To drive the TVs from CP/M, a custom video driver was built. This uses three relatively modern ATmega328P microcontrollers and the arduino-tvout library. All of these components are brought together on a stand made from wood and copper tubing, making it a functional as a desk top clock