Late last week, we saw a rather clever combination lock build that used only a single 74xx logic chip. [J. Peterson] read this post, and in a battle royale of geek one upmanship sent us a write up of the logic chip computer he built nearly 30 years ago at the University of Utah.
Around 1982 or 1983, [J. Peterson] took the Digital Hardware Lab at the University of Utah. The class was split into two semesters; during the fall semester, students would build a four digit, stack-based calculator that could add and subtract. That may sound easy, but everything – including reading the keyboard, multiplexing LEDs, and performing the mathematical operations – was done with gates and latches.
After Christmas break, the poor souls who had just finished their calculator were presented with another challenge due in four short months. The calculator built during the fall would turn into a full-blown computer, functionally similar to a PDP-8.
After months of work, and seeing the 70 people who showed up on the first day of class in September dwindle down to a handful in late April, [J. Peterson]’s computer was complete. The test program ran through a couple iterations, and the computer was immediately disassembled.
An awesome tale of digital design from only a generation ago. And you thought Verilog was hard.
In 1992, [Arpi] didn’t have much time for Ninja Turtles, Nintendos, and other wonderful wastes of time his fellow geeks were raised on. He was busy building a scanner for his Commodore 64. Although this very impressive build could have been lost to the sands of time, he pulled his project out of the attic for a “Try to use it again” party. Although this party is not a formal competition, we’re going to say that [Arpi] walked home that night with the most geek cred.
While there are no build details, there is a bunch of info to be gleaned from the gallery about how this machine was built. We’re pretty sure a good majority of the build was a typewriter at one point, and it looks like there’s a windshield wiper motor in there somewhere. Like this completely unrelated but similar build, [Arpi]’s scanner uses a photoresistor and a few LEDs to transfer image data to the custom software. In case you were wondering, yes, the ancient 5 1/4 floppy disk was still readable – one of the few advantages of the huge sectors on these disks.
Check out the videos of this scanner in action after the break, and if you’ve got a decades-old hack sitting in your attic (remember that acoustic modem you built?), send it in on the tip line.
Continue reading “Getting a home built scanner from ’92 up and running again”
Reader [HotDog-Cart] is an active member of the benheck forums and recently completed this Playstation 3 boomerang controller. The boomerang was originally shown with the Playstation 3 prototype and was severely panned by the press. [Josh] started with a cheap 3rd party controller that was approximately boomerang shaped. He enlarged the controller body ~20% using bondo. The internals were replaced with gear from an official Sony controller. It was finished with a coat of black paint. It’s definitely a nice build and the new internals mean it probably feels as good as any factory controller.