Homebrew Computer From The Ground Up

Building a retro computer of some sort is a rite of passage for many of us, with some building replicas or restorations of old Commodores, Ataris, and other machines from decades past. Others go even further back, to the time of the Intel 8008 or earlier, and a dedicated few will build something completely novel. This project from [3DSage] falls squarely in the latter category, with his completely DIY computer built component by component from scratch, including the machine code needed to run it.

[3DSage] starts with the backbone of every computer: the clock. He first demonstrates how a pair of NOT gates with a set of capacitors can be used as a rudimentary clock pulse, then builds a more refined version with a 555 timer and potentiometer for adjustable rates. Then, it’s on to creating a binary counter, which is a fundamental part of the memory system for this small computer, and finally, allows this circuitry to behave like a normal computer. Using a set of switches to store values in memory and stepping through them with the clock, the computer can be programmed to do plenty of tasks just like a modern microcontroller.

[3DSage] built this project a few years ago and has used it for real-world applications such as controlling servos, LED arrays, playing music, and other tasks. Although he has to program it using his own machine code by hand, it’s a usable computer in many ways. If you want to eschew modernity and build a retro computer in the style of the 1960s, though, this piece goes through what it would have been like to build a similar system in the era when these computers were more common. If you have a switch fetish, you might like to see how real computers worked back then, too.

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Test Your Capacity For Circuit Sculpture With Flashing Lights

Have you tried your hand at circuit sculpture yet? Well, if you were waiting for the ideal first project with a great build video to go along with it, keep reading. [4dcircuitry]’s 555-based flashing circuit sculpture ticks all the go-for-it boxen for us — the component list is short, the final circuit looks cool, and well, there are blinkenlights.

Of course, it’s not quite a zero-entry project. Although [4dcircuitry] makes it look oh-so easy build it in the video below, they are using 1206 components and an SOIC-packaged 555 timer here. On the other hand, they start by smartly laying everything out on double-stick tape before applying flux and soldering. Then when it’s time to run the wires that no one wants to see, [4dcircuitry] carefully tweezers it from the tape and flips it over, re-using the tape do solder up the back side.

Don’t have the patience to solder 1206? All component sizes are beautiful, as evidenced by this amazing circuit sculpture clock.

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photograph of custom PCB assembly of NE555-based electronic dice

NE555-Based Electronic Dice

It has become a bit of a running joke in the Hackaday community to suggest that a project could or should have been done with a 555 timer. [Tim] has rather taken this to heart with his latest Electronic Dice project, which uses three of the venerable devices.

If three seems like a lot of 555s to make an electronic die, then it may be worth considering that the last time we shared his project he was using 22 of them! Since then, [Tim] has been busy optimising his design, whilst keeping within the constraints of an old-school through-hole soldering kit.

Maybe the most surprising thing about this project is the purpose to which the NE555 devices are pressed. Rather than using them for their famous oscillation properties, they are in actual fact just being used as Schmitt Triggers to clean up the three-phase ring oscillator that is constructed from discrete transistors and passives.

scope trace of the electronic dice ring oscillator
Simulation trace of the three-phase ring oscillator before Scmitt Trigger stages

The ring oscillator cleverly produces three phase-shifted square waves such that a binary combination of the three phases offers six unique states. Six being the perfect number for a dice throw, all that then remains is to figure out which LEDs need to be switched on in which state and wire them up accordingly.

To “roll” the dice, a push-button powers up the oscillator, and stops it again when it is released, displaying the random end-state on the LEDs.

It can be fun to see what can be done using old technology, and educational to try to optimise a design down to the fewest parts possible.

[Tim]’s earlier project is here if you want to see how the design has evolved. The documentation on both of these iterations is excellent and well worth a read.

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Front of PCB for "SMT Garden" with glowing LEDs

Surface Mount Soldering Practice For Budding Electrical Engineers

Electronics components are steadily moving away from through hole parts to using surface mount technology (SMT) exclusively. While the small size of the SMT components can be intimidating, with a little practice, soldering can come pretty naturally. To help folks get over their fear of soldering small parts, [Alpenglow Industries] have created a charming board to practice SMT soldering skills on.

Back of "SMT Garden" PCB with only the 555 timer chips and inverter chip populated

[Alpenglow Industries] board, called the “SMT Garden”, combines a variety of SMT sizes ranging from 0402 to 1206 with beautiful PCB artwork to highlight the variety of LEDs on board. [Alpenglow Industries] provides detailed instructions on the various aspects of SMT soldering including what the terminology is and providing various techniques to help in soldering. The boards have practice “stalks” of surface mount component pads, so that folks can practice on columns of similarly sized SMT components to perfect their technique. The training stalks themselves aren’t functional but are there to provide practice for when folks feel comfortable soldering the LEDs, 555 timer and inverter chips to make the board functional.

[Alpenglow Industries] have provided all the KiCAD project files, gerbers and schematics available online. SMT soldering is more accessible than ever and when you can even use your phone as a microscope, it’s a good excuse to try it out, if you haven’t already.

Big Noise From A 555 And A Little Embroidery

[Sam Topley] specializes in making textile based, electronic instruments and sculptures using embroidery, and this little hoop packs some serious sound (Nitter).

The circuit is a riff on a classic 555 timer circuit, which produces a signal that is modulated by applying pressure conductive textile in different ways. The signal is then piped through a system built in a visual coding interface called MaxMSP, which allows [Sam] to get specific on how to control it. The program shifts the pitch and applies filtering, producing a dynamic dial-up tone-like sound as the user interacts.

To top it off, [Sam] uses vintage resistors  and tropical fish capacitors from the 60s that compliment the visual design and match the embroidery floss, they’re both beautiful and functional! This isn’t the only circuit of this kind [Sam] has made, she also produces tons of e-textile radios using similar techniques. We love how this project spans a ton of areas, analog circuitry, vintage tech, and soft circuits!

While we don’t see too many projects involving them come our way, e-textiles are certainly a fascinating topic. Our coverage of 2018’s “eTextile Spring Break” in New York is a must-read if you’re interested in exploring this technology, and the relatively recent news that MIT has developed a washable LED fabric has us hoping we’ll see more projects like this in the near future.

Modules described in the article (two copies of the challenge shown, so, two lines of modules)

Spaceship Repair CTF Covers Hardware Hacker Essentials

At even vaguely infosec-related conferences, CTFs are a staple. For KernelCon 2021, [Tyler Rosonke] resolved to create a challenge breaking the traditions, entertaining and teaching people in a different way, while satisfying the constraints of that year’s remote participation plans. His imagination went wild in all the right places, and a beautifully executed multi-step hardware challenge was built – only in two copies!

Story behind the challenge? Your broken spaceship has to be repaired so that you can escape the planet you’re stuck on. The idea was to get a skilled, seasoned hacker solving challenges for our learning and amusement – and that turned out to be none other than [Joe “Kingpin” Grand]!

The modules themselves are what caught our attention. Designed to cover a wide array of hardware hacker skills, they cover soldering, signal sniffing, logic gates, EEPROM dumping and more – and you have to apply all of these successfully for liftoff. If you thought “there’s gotta be a 555 involved”, you weren’t wrong, either, there’s a module where you have to reconfigure a circuit with one!

KernelCon is a volunteer-driven infosec conference in Omaha, and its 2022 installment starts in a month – we can’t wait to see what it brings! Anyone doing hardware CTFs will have something to learn from their stories, it seems. The hacking session, from start to finish, was recorded for our viewing pleasure; linked below as an hour and a half video, it should be a great background for your own evening of reverse-engineering for leisure!

This isn’t the first time we’ve covered [Tyler]’s handiwork, either. In 2020, he programmed a batch of KernelCon badges while employing clothespins as ISP clips. Security conferences have most certainly learned just how much fun you can have with hardware, and if you ever need a case study for that, our review of 2019 CypherCon won’t leave you hanging.

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

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.

A Microscopic View Of the 555 Die

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.