Piano Doorbell Adds Music To Your Home

June 8, 2025 by Lewin Day 16 Comments

Regular ding-dong doorbells are fun and all, but it can be nice to put something a little more special by your front door. To that end, [Arpan Mondal] built this neat little piano doorbell to make visiting his home just a touch more fun.

The heart of the build is an ESP32 microcontroller. It’s responsible for reading the state of five 3D printed piano keys: three white, two black. It’s nowhere near a full octave, but for a doorbell, it’s enough. When a key is pressed, the ESP32 plays a short audio sample embedded within the program code itself. This is done with the help of a PAM8403 audio amplifier module, which jacks up the output to drive the doorbell speaker loud enough to be heard throughout the home. It’s not exactly studio quality audio, but for a doorbell, it sounds pretty solid.

If you’re looking for a fun and easy build to make your home just a little bit more whimsical, it’s hard to beat something like this. Your musical friends will love it—they might even develop an intro riff of their very own. We’ve featured some other fun doorbell builds before, too—the best of which are the Halloween projects.
Continue reading “Piano Doorbell Adds Music To Your Home” →

When Wireless MIDI Has Latency, A Hardwired Solution Saves The Day

June 7, 2025 by Lewin Day 14 Comments

[Moby Pixel] wanted to build a fun MIDI controller. In the end, he didn’t build it just once, but twice—with the aim of finding out which microcontroller was most fit for this musical purpose. Pitted against each other? The ESP32 and Raspberry Pi Pico.

The MIDI controller itself is quite fetching. It’s built with a 4 x 4 array of arcade buttons to act as triggers for MIDI notes or events. They’re assembled in a nice wooden case with a lovely graphic wrap on it. The buttons themselves are wired to a microcontroller, which is then responsible for sending MIDI data to other devices.

At this point, the project diverges. Originally, [Moby Pixel] set the device up to work with an ESP32 using wireless MIDI over Bluetooth. However, he soon found a problem. Musical performance is all about timing, and the ESP32 setup was struggling with intermittent latency spikes that would ruin the performance. Enter the Raspberry Pi Pico using MIDI over USB. The hardwired solution eliminated the latency problems and made the controller far more satisfying to use.

There may be solutions to the latency issue with the wireless ESP32 setup, be they in code, hardware configuration, or otherwise. But if you want to play with the most accuracy and the minimum fuss, you’ll probably prefer the hardwired setup.

Latency is a vibe killer in music as we’ve explored previously.

Continue reading “When Wireless MIDI Has Latency, A Hardwired Solution Saves The Day” →

Building An Analog Echo Plate

June 5, 2025 by Lewin Day 7 Comments

These days, when you think reverb, you probably think about a guitar pedal or a plugin in your audio software. But you can also create reverb with a big metal plate and the right supporting electronics. [Tully] from [The Tul Studio] shows us how.

Basically, if you’ve ever smacked a big sheet of metal and heard the thunderous, rippling sound it makes, you already understand the concept here. To turn it into a studio effect, you use transducers to deliver the sound into the plate of metal, and then microphones to pick it back up again at some other point on the plate. Since the sound takes time to travel through the plate, you get a reverb effect.

[The Tul Studio] used a huge cold-rolled steel plate, standing one meter wide and two meters tall. The plate itself is hung from picture chain, which is strong enough to carry its weight. Old car tweeters are repurposed to act as pickups, while a larger speaker is used to drive sound into the plate. “The key to making it sound not like a tin can is the actual EQ and the electronics,” [Tully] explains, providing resources for this purposes.

We love lots of lovely reverbing things around these parts; oddball delays, too! Video after the break.

Continue reading “Building An Analog Echo Plate” →

Passive Saturation Box Is A Cheap Way To Distort Your Sound

June 4, 2025 by Lewin Day 10 Comments

Distortion pedals and overdrive effects usually have a bunch of lovely transistors or op-amps inside and lots of knobs and dials to tweak the sound to your personal taste. However, it’s possible to get some crunchiness in your audio signal without all that fuss, as [Simon Hutchinson] demonstrates with his $2 “analog saturation box”.

The effect is achieved quite simply by installing a pair of diodes in opposite orientations, connected from the signal path to ground. This configuration is also known as wiring diodes in “anti-parallel.” When the signal increases in amplitude beyond the diode’s forward voltage, the diode conducts and the signal’s peak is clipped off, which creates a distorted tone. Since there are two diodes, one in each orientation, both the tops and bottoms of the AC audio signal are clipped in this manner.

The amount of clipping is highly dependent on the diodes chosen and the strength of the signal you’re working with. Silicon diodes clip around 0.7 V, while germanium diodes clip at about 0.3 V, but that doesn’t give you much flexibility. You can work with this to some degree, though. You can up the minimum clipping level by stacking more diodes in series in each direction, or you can put in a potentiometer to vary your signal’s level before it hits the diodes. Really, though, this hard voltage limit is why more commonly, we use active distortion or overdrive effects that have more options for gain and level and such.

[Simon Hutchinson] does an able job of explaining the effect and demonstrates its use with some simple beats. As a passive device, it’s pretty one note—there’s no EQs to mess with the frequency response, and no ability to change anything else about the sound, either. Still, it’s interesting to hear the effect it does have on a signal, and you might just find this is all the distortion you need. If you’d rather go into full-fat distortion though, we’ve covered that too.

Continue reading “Passive Saturation Box Is A Cheap Way To Distort Your Sound” →

3D Printing A Modular Guitar Means It Can Look Like Whatever You Want

June 4, 2025 by Lewin Day 24 Comments

Got some spare filament and looking to build a guitar you can truly call your own? [The 3D Print Zone] has created a modular 3D printable guitar system that lets you easily mix and match different components for the ultimate in customization.

The build is based around a central core, which combines the pickups, bridge, and neck into one solid unit. This is really the heart of the guitar, containing all the pieces that need to be in precise alignment to get those strings vibrating precisely in tune. The core then mounts to a printed outer body via mating slots and rails, which in the main demo is made to look like a Les Paul-style design. This outer body also hosts the volume, tone, and pickup controls. Output from the pickups travels to the controls in the outer body via a set of metallic contacts.

What’s cool about this build is that the sky really is the limit for your creativity. As the video below demonstrates, the main build looks like a Les Paul. But, armed with the right CAD software, you can really make a guitar that looks like whatever you want, while the 3D printer does all the hard work of making it a reality. The files to print the guitar, along with the pickups and other components, are available as kits—but there’s also nothing stopping you from working up your own printed guitar design from scratch, either.

We’ve seen some other great 3D printed guitars before, too.

Continue reading “3D Printing A Modular Guitar Means It Can Look Like Whatever You Want” →

Building An Eight Channel Active Mixer

June 3, 2025 by Lewin Day 29 Comments

There are plenty of audio mixers on the market, and the vast majority all look the same. If you wanted something different, or just a nice learning experience, you could craft your own instead. That’s precisely what [Something Physical] did.

The build was inspired by an earlier 3-channel mixer designed by [Moritz Klein]. This project stretches to eight channels, which is nice, because somehow it feels right that a mixer’s total channels always land on a multiple of four. As you might expect, the internals are fairly straightforward—it’s just about lacing together all the separate op-amp gain stages, pots, and jacks, as well as a power LED so you can tell when it’s switched on. It’s all wrapped up in a slant-faced wooden box with an aluminum face plate and Dymo labels. Old-school, functional, and fit for purpose.

It’s a simple build, but a satisfying one; there’s something beautiful about recording on audio gear you’ve hewn yourself. Once you’ve built your mixer, you might like to experiment in the weird world of no-input mixing. Video after the break.

Continue reading “Building An Eight Channel Active Mixer” →

ESPer-CDP Plays CDs And Streams In Style

May 31, 2025 by Tyler August 12 Comments

What do you get when you combine an ESP32, a 16-bit DAC, an antique VFD, and an IDE CD-ROM drive? Not much, unless you put in the work, which [Akasaka Ryuunosuke] did to create ESPer-CDP, a modern addition for your hi-fi rack.

It plays CDs (of course), but also can also scrobb the disks to Last.fm, automatically fetch track names and lyrics for CDs, and of course stream internet radio. It even acts as a Bluetooth speaker, because when you have an ESP32 and a DAC, why not? Of course we cannot help but award extra style points for the use of a VFD, a salvaged Futaba GP1232A02. There’s just something about VFDs and stereo equipment that makes them go together like milk and cookies.

close up of front of machine showing VFD. — Between the panel and the VFD, this could almost pass as vintage Sony.

In terms of CD access, it looks like the IDE interface is being used to issue ATAPI commands to the CD-ROM drive to get audio out via S/PDIF. (Do you remember when you had to hook your CD drive to your sound card to play music CDs?) This goes through a now-discontinued WM8805 receiver — a sign this project has been in the works for a while — that translates S/PDIF into an I2S stream the ESP32 can easily work with.

Work with it it does, with the aforementioned scrobbing, along with track ID and time-sinked lyrics via CDDB or MusicBrainz. The ESP32 should have the computing power to pull data through the IDE bus and decode it, but we have to admit that this hack gets the job done — albeit at the expense of losing the ability to read data CDs, like MP3 or MIDI. [Akasaka Ryuunosuk] has plans to include such functionality into v2, along with the ability to use a more modern SATA CD-ROM drive. We look forward to seeing it, especially if it keeps the VFD and classic styling. It just needs to be paired with a classic amplifier, and maybe a DIY turntable to top off the stack.

Thanks to [Akasaka Ryuunosuke] for the tip. If you also crave our eternal gratitude (which is worth its weight in gold, don’t forget), drop us a tip of your own. We’d love to hear from you.