It’s technically true that any piece of software can be reproduced in hardware, although modern software’s size and complexity generally makes this a non-starter. But if we go far enough back in time, older software becomes easier and easier to implement in hardware. The original DOOM from 1993 might one day be recreated in full this way, but that day is not today. Instead, [Nick] has recreated the original music from that game, playing the opening track in nothing but 555 timers.

The circuit starts with a 555 timer that acts as a system clock with a rate of just over 7 Hz. These pulses feed a binary counter which in turn feeds a decoder, giving the circuit 15 positions. Each output of the decoder feeds to a diode matrix which stores information about what pitch the circuit should play. The circuit only needs to play six pitches so the diodes effectively connect each moment in time to one of these six notes. From there the circuit feeds into a set of switches which select different resistor networks of another 555 which is actually responsible for producing sound. The resistor networks have different values to adjust the timing of the 555 to produce different pitches.

Of course this entire exercise is largely academic as almost any microcontroller would be able to be programmed to play this chiptune quite easily, but it’s not a bad idea to get down into the weeds of digital logic from time to time in order to refine one’s skills and knowledge about what’s really going on in the inner workings of circuits. Or, go even deeper than that and build the logic gates themselves from first principles.

Your desk or bench is a work area, so why not make it look the part? That’s the idea behind the miniature blinking traffic barrels that [Glen Akins] recently put together. Of course, just a single blinking light doesn’t really sell the idea of a busy construction zone, so he spent a somewhat surprising amount of time and effort optimizing the design for small-scale production.

The end result is a fascinating write-up that dives into the design decisions [Glen] made. Every aspect of this project, from the overhang of the “handle” on the 3D printed barrel to the number of passive components on the PCB was carefully considered. Critics may say [Glen] put too much thought into something that didn’t need to be so complex, but projects like these are an excellent way to keep your skills sharp — there’s no such thing as practicing too much.

Starting with the design of the barrel itself, we appreciate that [Glen] kept the capabilities of his desktop 3D printer in mind. By breaking the design up into multiple pieces and avoiding overly steep angles, he produced a design that prints cleanly without the need for support material. His step-by-step documentation and screenshots also serve as a great introduction to designing parts in Fusion if that’s something you’re interested in.

From there, things switch over to the electronics. Some in the audience will bemoan that he’s using a PIC12F1612 microcontroller to blink a single LED instead of a 555, but [Glen] brought the receipts on this one. Not only does the PIC offer more flexibility in terms of getting the blinking to look the way he wants, but it requires fewer passive components on the board and is considerably more energy efficient than the iconic timer IC. Even if you ignore all the other advantages, he calculates that going with a 555 would have cut the battery life of the finished product by approximately 15%.

This is one of those projects that’s difficult to summarize in such a terse format, as every time you think the write-up must be about over it takes a new turn on you. We were mildly bemused when the second iteration of the PCB popped up, but by the time he introduced the custom programming adapter board, we knew [Glen] wasn’t messing around.

Unsurprisingly, this isn’t the first time we’ve seen [Glen]’s handiwork. You may recall seeing his RP2040-powered sound board earlier this year, but his name has been popping up on these pages for more than a decade now.