Upgrading A Soviet Calculator With A Modern CPU

January 27, 2022 by Robin Kearey 17 Comments

Today’s supply chain issues can make it hard to buy microcontrollers, or really any kind of semiconductor. But for those keeping retrocomputers alive, this problem has always existed: ancient components might have been out of production for decades, with a dwindling supply of second-hand parts or “new old stock” as the only option. If a rare CPU breaks, you might have no option but to replace the entire computer.

[Piotr Patek] ran into this issue when he obtained an Elektronika MK-85 programmable calculator with a broken CPU. Unable to find a replacement, he decided instead to build a pin-compatible CPU unit based on an STM32 microcontroller. Of course no modern CPU is pin-compatible with a Soviet design from the 1980s, so [Piotr] had to design a small interposer PCB to match the original pinout. This also gave him enough space to add an efficient DC/DC converter chip that generates the 2.5 V supply for the STM32.

As for the software, [Piotr] managed to port the original BASIC interpreter, which was written in PDP-11 assembly, to a modern equivalent written in C. While he was at it, he fixed a few bugs that had been sitting there for about 35 years. The updated CPU also allows the MK-85 to run circles around its contemporary siblings: [Piotr] timed it to be about thirty times faster than the original chip, while using a comparable amount of power.

If you also happen to have an MK-85 with a dodgy CPU, you’ll be pleased to find that the schematics and source code to [Piotr]’s modification are all available on his blog. This is probably the first calculator CPU update we’ve seen, although we’ve featured other ancient calculators updated with new firmware, and some completely new calculator designs based on classic hardware.

Thanks for the tip, [cmholm]!

Young Maker Mixes Traditional Japanese Construction With Modern Art

January 25, 2022 by Ryan Flowers 4 Comments

We’re Makers. By definition, we make things. Some of us prefer to build from scraps, while others like to make their own IC’s in their garage. [Make With Miles] on the other hand prefers one of the oldest types of making around: woodworking. And in this build, he goes a step further by using a very old Japanese method of woodworking called Kumiko to build a Stratocaster style electric guitar. The results are absolutely stunning as you can see in the video below.

Inspired by a challenge put forth by [The Modern Maker Podcast] to build a woodworking project that ties into another hobby that isn’t related to woodworking, [Miles] knocked it out of the park by including several art forms in this one-off Strat.

The centerpiece of this guitar build is the Kumiko style of construction used within the body. Kumiko is a Japanese method of assembling wood without the use of fasteners. Developed around 600-700AD, Kumiko is as much a construction method as an art form. [Miles] went further by filling the Kumiko framework with blackened epoxy resin which was then sanded and polished. Decals bring the headstock into the motif, but the attention to details goes much, much further. Be sure to watch the video so you can get an appreciation for the high level of workmanship that this young man displays.

That’s right- [Miles] isn’t a maker with decades of experience. In fact in 2017, one of his YouTube videos was “12 yr Old Builds a Row Boat!!!” [Miles], our hats are off to you and we look forward to seeing your art progress, for you truly have commanded the attention of the maker community that you are so rightfully part of.

Just as [Miles]’ guitar hides some great hacks, so does this guitar with Hot Swappable pickups. Thanks to [Keith] for sending this on to the Tip Line!

Continue reading “Young Maker Mixes Traditional Japanese Construction With Modern Art” →

555 Teardown Isn’t Just A Good Time, It’s To Die For

January 25, 2022 by Ryan Flowers 10 Comments

It seems only appropriate that hot on the heels of the conclusion of Hackaday’s 555 Timer Contest that [Ken Shirriff] posts a silicon die teardown of an early version of a hacker’s favorite chip, the 555.

Starting with a mystery chip from January 1973, [Eric Schlaepfer] painstakingly sanded down the package to reveal the die, which he deemed to be a 555 timer. Why didn’t they know it was a 555 timer to start? Because the package was not marked with “555” but rather some other marks that you can see in the blog post.

In addition to a great explanation of how the 555 works in general, [Ken] has taken a microscopic look at the 555 die itself. The schematic of a 555 is easily available, and [Ken] identifies not just sections of the die but individual components. He goes further yet by explaining how the PNP and NPN resistors are constructed in silicon. There’s also a nice and juicy bit of insight into the resistors in the IC, but we won’t spoil it here.

Be sure to show your love for the winners of the 555 contest, or at the very least check out the project that took the stop spot: a giant sized 555 that you don’t need a microscope to see inside of.

DIY “Solid State Drive” Puts Four Bytes In Your Pocket

January 23, 2022 by Tom Nardi 71 Comments

In a relatively short amount of time, the average capacity of USB flash drives has skyrocketed. It wasn’t so long ago that two and four gigabyte drives were considered to be on the high end, but today you can grab a 512 GB drive for less than $50 USD. In fact they’ve gotten so large that it can feel wasteful using them for some tasks, and we occasionally find ourselves wishing we could find some modern USB drives that didn’t rival the storage capacity of our whole computer.

That said, this USB-C tetrabyte drive created by [Glen Akins] might be slightly too small for our tastes. No, that’s not a typo. As in the Greek tetra, this drive can hold a massive four bytes at a time. Even better, you don’t need a computer to write to it: the 32 DIP switches let you key in the content on the fly, bit-by-bit.

Reading out the first byte from the DIP switches.

As explained in a Twitter thread, [Glen] was inspired to create this gadget after another user posted a picture of a 32 position DIP switch with a caption that said it was a “One Tetrabyte SSD” back in December. He apparently couldn’t track down the same switch, but the four red Grayhill 76 Series switches arguably make it a bit clearer when entering in your bytes.

Each of the individual DIP switches are connected to one of the GPIO pins of the 8-bit EFM8UB2 microcontroller, and the code simply reads the state of each pin in order and saves the binary results in a variable to put together the “file” it presents to the OS when plugged in.

We’ve seen our fair share of unusual USB flash drives in the past, but this one is truly in a league of its own. Can’t say we can think of any four bytes of data important enough to hold on a dedicated piece of hardware, but we certainly appreciate the effort to store it in the most robust way possible.

Thanks to [J. Peterson] for the tip.

Congratulations Winners Of The 555 Timer Contest!

January 20, 2022 by Elliot Williams 25 Comments

Sometimes the best inspiration is limitation. The 555 timer does “one thing” — compares a voltage to a couple thresholds and outputs a signal accordingly. It’s two comparators, a voltage ladder, and a flip-flop. And yet, it’s the most sold single chip of all time, celebrating its 50th birthday this year! So when Hackaday runs a 555 Timer Contest, hackers of all stripes come out with their best work to show their love for the Little DIP That Could.

The Winners

Far and away the favorite entry was the Giant 555 Timer by [Rudraksha Vegad]. Every one of our judges rated it in the top five, and it took top honors twice. On its face, this is a simple “giant 555 in a box” build, but have a look under the hood. Each sub-module that makes up the 555 — comparators, flip-flop, and amplifier — are made from salvaged discrete parts in actual breadboard fashion, soldered to brass nails hammered into wood. As an end product, it’s a nice piece of woodworking, but as a process of creation, it’s a masterwork in understanding the 555 at its deepest level. We should all make one!

The Menorah555 is a simple design with some very nice tricks up its sleeve. Perhaps the cutest of which is pulling the central candle out and lighting the others with it — a trick that involves a supercapacitor and reed switches. Each of the candle lighting circuits, however, use a 555 timer both for its intended purpose of providing a timed power-on reset pulse, and another 555 is used as a simple flip-flop. It’s a slick design, and a great user interaction.

The Cyclotone Mechanical Punk Console Sequencer is a rotating tower of circuit sculpture and noisemakers. This one looks great, is amazingly well documented in the video series, and uses a billion clever little tricks along the way. The 555’s role? Each of the four levels is the classic Atari Punk Console circuit.

All three of these projects win a $150 shopping spree at Digi-Key. That’s a lot of timers!

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Drill Does Well In Double Duty As Well Drilling Drill

January 19, 2022 by Ryan Flowers 18 Comments

There are a large number of methods commercially used to bore a hole into the ground for the sake of extracting drinking water, and the all require big loud equipment. But what if you just want a small well? Do you really have to call in the big guns? [The Working Group on Development Techniques] is a student association at the University of Twente in the Netherlands who shows in the video below the break that some simple homemade fixtures and a powerful hand drill are quite enough to do the job!

There's more to drilling a drill than drilling with a drill — There’s more to drilling a well than just drilling well

Chief among these fixtures is a swiveling mechanism that serves to hold the drill and its weight, give control over the drill, and inject water into the pipe that the drill bit is attached to. Plans for the swivel are made available on [WOT]’s website. What looks to be a DIY drill bit uses commercially available diamond tips for hardness.

What makes the video remarkable is that it discusses every stage of drilling the bore hole, lining it with casing, and then making it suitable for pumping water from. The video also discusses the chemicals and methods involved in successfully drilling the hole, and gives an overview of the process that also applies to commercially drilled wells.

Naturally you’ll want to make sure your drill is corded so that you can drill for long periods, but also so that it doesn’t grow wings and fly away!

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A Dodgy Dial Gets A Teardown And Some Oil

January 16, 2022 by Jenny List 8 Comments

The pulse-dial telephone and its associated mechanical exchange represents the pinnacle of late-19th and early-20th century electromechanical technology, but its vestiges have disappeared from view with astonishing rapidity. [Matthew Harrold] is a telecoms enthusiast who’s been kind enough to share with us the teardown and refurbishment of that most signature of pulse-dial components, a telephone dial. In this case it’s on a rather unusual instrument, a British GPO outdoor phone that would have been seen in all kinds of industrial and safety installations back in the day and can probably still be found in the wild today if you know where to look.

The teardown soon identifies a dial that runs very slowly and is sorely in need of a clean. There follows a detailed part-by-part dismantling of the dial mechanism, followed by a careful clean, polish, and reassembly. He notes that a previous owner had used grease to lubricate it, probably the reason for its slow operation.

The result is a smoothly running dial and a refurbished phone that would probably last another half-century or more before needing more maintenance. It’s enough to make others who’ve experimented with pulse dial phones very envious.