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.

Humans of all ages like music, but you can’t exactly pass a toddler the aux cable. That’s not to say the younger set don’t have their own particular tastes– they absolutely do, and they absolutely love to take control and inflict them on the rest of us. [nbr23] has a toddler who loves both music and tactile controls, and decided to combine the two for them with a project he calls Radio-Gaga, which is a gutted Panasonic radio that calls up tunes via Home Assistant.

Interestingly enough the radio is now just a remote control– the speaker has been removed along with the rest of the radio hardware. The buttons and dials are still there, though, letting the toddler control what tunes are on offer and at what volume via couple of potentiometers hooked to an ESP32. The sound itself is being served up from the homelab to a USB speaker. There’s one notable flaw with this architecture: if the batteries die on the remote, “Let it Go” does not until an adult intervenes manually or recharges the remote.

One interesting lesson [nbr23] wanted to share was that he was able to improve an unsatisfactorily slow startup time by assigning the device a static IP on his network– apparently the single longest step in getting the tunes going was negotiating a DHCP lease. Skipping that gets the tunes playing in under a second, which is fast enough even for the most impatient of tiny humans.

If you prefer a more self-contained device, we’ve seen toddler jukeboxes that keep storage and speaker built-in, many with NFC control. 

We cover so many projects here at Hackaday that lead the author down a rabbit hole of technological investigation that distracts us from the task of bringing them to you. Such a project is polyUAnalog, a very modern take on an analogue synthesizer. If you are imagining a synth of old with modules and patch cables, think again. The modern way to do this is it seems to use an individual synthesizer chip for each voice, resulting in a very versatile instrument indeed.

The integrated circuit in question is the AS3397, which when coupled on a PCB with a Raspberry Pi Pico makes for a self-contained single-voice analog synth. It’s controlled via I2C from a conductor board for which frustratingly the README doesn’t give a processor, but we think may be powered by another Pi Pico. This board does the job of taking MIDI and other controls, and farming them out tot he individual voices. The prototype has ten, but it can support many more.

It’s the work of a pair of researchers from the University of Angers in France, and we’re told it’s a side project from their work in the field of spectroscopy. There’s a video about it which we’ve placed below the break, and they’ve also written a paper about it.

In theory, MIDI is an electrical and protocol standard that allows any such equipped instrument or computer to talk to any other. But as the wonderfully named [Knob Monster] will tell you, when the computer is new, and the instrument is old, it ain’t that simple.

They specialise in using the Web MIDI interface to allow browser control of an instrument. This might typically be done with a USB to MIDI interface, but in this lies a problem. The 8-bit microprocessor on a 1983 synth has problems keeping up with the rapid-fire data that spews relentlessly from the supercomputer-grade machine controlling it, and bad things happen as a result.

Expensive MIDI interfaces have a buffer built in, but a better solution lies in the Web MIDI code itself. They detail how to use the Web MIDI API’s built-in packet scheduler to slow things down a little and let your Yamaha DX7 chill a bit.

Meanwhile, if you need a USB to MIDI interface, we’ve covered one in the past.

When we think of 1960s synthesizers it’s usual to imagine instruments with vast arrays of controls and patch cables for configuring their many filters, oscillators, and other parameters. They created the templates for much of what we know today as electronic music.

In all the rush to look at full-blown synths though, it’s easy to forget their more mundane cousin, the electric organ. These instruments graced many a ’60s suburban home or church hall, and [Emma Repairs] has an interesting one. It’s a Philips Philicordia, and it’s sent us here at Hackaday down one of those rabbit holes when we should really be writing.

The instrument is a relatively straightforward single voice electric organ on the outside, but under the hood it’s a different matter. In an age when the transistor was revolutionizing electronic music, the folks in Eindhoven designed this one using tubes. There are a set of conventional enough tubes performing the role of amplifiers and oscillators, but the real party piece of this unit is the array of neon tube dividers. A neon bulb can be used as a switching element, and in those days when affordable digital logic chips were several years away, it made sense to use them in digital circuits.

The inside of the Philicordia is a feast of vintage Philips parts that will be instantly familiar to anyone who’s worked on Western European electronics of this era. The exterior design of the instrument screams understated early-1960s cool, and after she’s introduced it you can hear her playing it in the video below. Further down that rabbit hole we found that one of these instruments provided the distinctive organ sound on Chris Montez’s 1962 hit Let’s Dance, so they weren’t all uncool.