A little over a month ago, we featured a project from [Igor] who built 64 bits of DRAM from scratch using discrete components. Jokes about memory pricing aside, he did have a use case for such a small amount of memory — he is using it in a custom-built drum machine. But featuring the memory build and not the drum machine was perhaps putting the cart before the horse, so in this video, [Igor] shows off the construction of each part of his impressive 16- or 64-step sequence drum machine.

This isn’t Igor’s first drum machine, either, although his previous build was a bit more limited. It had fewer steps in the sequence and didn’t quite have the range of his newer model. The upgraded version can play more steps but also includes force-sensitive drum pads based on piezo sensors and more voices (drums) as well. Each voice is built electronically using various op-amps and passive components, and [Igor] has the schematics for each of them, as well as every other part of the drum machine, for those looking to recreate any part of this on their own. There’s a lot going on in this lengthy video as well, so for the musically inclined, it’s worth taking a look in full.

Now that our horse is in the correct position in front of the cart, it’s worth going back and looking at the memory build if you missed it when it first ran. A small amount of memory makes the machine programmable rather than just playable, and truly expands the capabilities of a machine like this in the recording studio.

Full body tracking in VR applications involves attaching sensors to one’s body, and [Jaki] has a DIY method to do it on the cheap: the Vive Tracker Lite project repurposes Vive controllers as lighthouse-based trackers, no hardware modifications required.

A common method of doing body tracking is to strap on some Vive trackers. Those are extremely hacker-friendly pieces of hardware, but [Jaki] observed that older Vive VR controllers can be had for cheap, and already contain everything a tracker needs. Some new firmware and a custom mount is all it takes to turn them into perfectly usable body trackers.

But what about a wireless receiver? [Jaki] has that covered as well with the $5 Viva Dongle, which uses a Pro Micro NRF52840 to act as a cheap DIY alternative to the official dongle hardware.

We appreciate the effort put into making this project accessible to everyone, even novices. [Jaki]’s put effort into a Python program with a full GUI to make the flashing of firmware as easy as possible for both projects. Experimenting with body tracking in VRChat or games with mods is just some recycled hardware away.

Granted, a Vive controller is not the slimmest piece of hardware, but all it takes is a firmware change and a 3D-printed fixture to make a perfectly serviceable tracker. That being said, we’re sure an enterprising hardware hacker may crack a controller open and embark on a serious rebuild, or even interface to some of the inputs in a clever way. If you’ve done that or know of someone who has, drop us a note on our tips line because we’d love to see it.

[lcamtuf] is not just a calculator superfan, but also a skilled builder. That much is evident in the fabulous  design of Calcumator 2000, an electromechanical calculator that uses voltmeter readouts as digits (plus one at the bottom to represent decimal place). There are plenty of high-quality build images, so give it a look!

Calcumator 2000 is a bit of a love letter to a time when display technology hadn’t quite yet produced anything suitable for calculator use. This resulted in calculator designs that are generally unrecognizable compared to the 7-segment display based devices we see today. The Calcumator 2000, in all its electromechanical glory, would have fit right in that era.

The Calcumator 2000 has all the usual buttons one would expect from a simple calculator and drives a total of seven readouts, one of which acts as the decimal point. The idea of using voltmeters as digit displays came from [lcamtuf]’s voltmeter clock, an earlier work with a similar attention to detail in its design and assembly.

We want to take a moment to admire how clean the blue panel is. [lcamtuf] made it by painting one side of an acrylic panel, cutting the letters and design out on a CNC mill, then filling with white paint. The depth of the cuts gives the white elements a nifty multi-layer effect that really complements the design.

Want to see it work? Oh yes, you do. Check out the video, embedded just below.