Early computer kits aimed at learning took all sorts of forms, from full-fledged computer kits like the Altair 8800 to the ready-made MicroBee Computer-In-A-Book. For those just wanting to dip their toes in the computing world, many low-cost computer “trainers” were released, and Japan had some awesome ones. [Jason Jacques] shows off his Gakken Micro-Computer FX-System (or is it the FX-Computer? Or maybe the FX-Micom? It seems like they couldn’t make up their minds). In any event, it was a combination microcomputer and I/O building blocks system running a custom version of the Texas Instrument TMS1100 microprocessor. Specifically designed to introduce users to the world of computing, the included guide is very detailed and includes 100 example programs and lots of information on how all the opcodes work.
This 4-bit system is similar to the Kenbak computer, with a very simple instruction set and limited address space. However, adding electronic components in plastic blocks brings this machine to a new level of interactivity. Connections can be made to and from the microcomputer block, as well as to the on-board speaker and simple input/output pins. The example circuit displayed on the front cover of the box enables the microcontroller to connect to the speaker and allows a switch to light up a small incandescent bulb. We can imagine many users wiring up all sorts of extra components to their FX-Computers, and with the advent of 3D printing, it wouldn’t be difficult to create new blocks to insert into the grid.
This exact model was eventually released in the US in a modified (and possibly slightly less cool-looking) version available through Radio Shack called the Science Fair Microcomputer Trainer. It’s reminiscent of the ubiquitous 100-in-1 circuit kits but with the same microcomputer block added in. Both are very difficult to find, and the fact that [Jason] has both in near-immaculate condition is simply amazing! He writes some self-modifying code, taking advantage of the fact that the “variable” storage and registers are really just RAM locations. Be sure to watch the full video to see the wonderfully preserved original machine running some hand-assembled 4-bit programs! We’ve also seen people supercharge the Radio Shack version with a new CPU.
Back in the ’80-ies I found the Microprofessor ( https://en.wikipedia.org/wiki/Micro-Professor_MPF-I ) a very intriguing piece of kit. It had all sorts of extension modules, and it was also easy to make your own. But I was too young to be able to afford to buy it. And data entry would have been quite a nuisance too. It was also the same era as the start of the home computer with the MSX and commodore 64 which had much better data entry methods (keyboard and monitor or TV).
Things like writing out assembly and entering opcodes (as shown @21:47) gets boring really quickly.
In the end, I just was a bit too young for it all. My first PC was a 80386SX, and I did not start with microcontrollers until they became really cheap (Short dabble with 16F84, but I hated it’s instuction set, and then the AT90s2313, which had GCC and that was truly amazing). Before that, you had to buy uC’s in ceramic pagackes and a glass screen to erase them with UV light. Those chips were quite expensive.
There also were single-board computers (once aka EMUFs in my country) with a serial terminal and EPROM storage.
The 8052AH-BASIC chips were popular, for example.
The basic interpreter is now made Freeware and improved and can be used with 8052 compatibles.
The AH BASIC can store files on EPROM, have interrupts and other cool features.
Another microcontroller was the PICAXE chip, a basic stamp. Was popular about 20 years ago or so.
Here in Germany, the C-Control units by Conrad Electronic were semi popular, too.
I actually still have an MPF, in mint condition. Nowadays I take it out of storage as few times as possible. :-) Data entry is not as bad as it seems, because there’s only 256 bytes of RAM available (although it is expandable). So you’re not entering modern amounts of data. And even back then you could hook it up to a cassette recorder to save/load programs and data.
Thanks for this great writeup and for highlighting my video. Happy to answer any questions!
Silly question, but do you mind grabbing measurements?
The form factor is neat, and would be a great way to teach my nieces and nephews some electronics/computer science stuff in a retro way. 80s form-factor/aesthetic is currently holding their attention something fierce. But I don’t want to use an original vintage one for them, as kids are gonna be kids and potentially cause spills/damage, and these things are rare.
I want to 3d print and build out a couple of replicas for them. Length, width, height, and measurements of blocks so I could make new ones to fit the grids are all I really need. I could figure out the rest, I think.
If not, no worries! Just a shot in the dark.
The pegboard is 14.1mm between pegs. Each peg is 3.8mm in diameter and 8.6mm high. The pegboard of the FX series is 11×6, the EX series is 8×6, the mini is 5×5.
Each block is 17.5mm square, 18mm high to the shoulder, 23mm including the pip. The pip is 12.8mm diameter. Each edge of the block has a centred recess 0.35mm deep, and 3.1mm wide in which an (optional) metal contact is placed. Minimum block thickness (i.e. recess to internal wall) is 1mm. The contacts are 2.9mm wide and are vertically convex away from the block, with a maximum protrusion of 0.75mm. Each corner of the block has a full-height quarter circular intrusion to fit the pegboard.
There is this existing model on Thingiverse, which is a reasonable approximation, but the corners are not properly hollowed to allow use with an actual unit.
https://www.thingiverse.com/thing:5711055
Hope that helps
I had the Radio Shack version as a kid and really enjoyed it. For a challenge (and a competition), a couple of years ago I made a simulator in Scratch (!): https://www.instructables.com/Radio-Shack-Microcomputer-Trainer-Emulator-in-Scra/
Awesome work on the Scratch emulator. I do give it a little shout-out at the end of the video. I’ve also linked to it in the video description, along with providing copy-n-pastable versions of the programs I demonstrated. They work great!
Here’s a demo of interfacing the Radio Shack version to allow for easier programming. https://youtu.be/JyvF2UcCMc4?si=KUD7c1L_gh1pZdMq
I invented a modern version of this, called the Gridboard. I sell them at grid-board.com .
A similar “electronics Lego block” idea was realized as early as 1965 by Georg Greger – the Lectron System still has many folllowers to this day.
https://en.wikipedia.org/wiki/Raytheon_Lectron