Modern Tech Meets Retro 7-Segment

June 23, 2025 by Matt Varian 7 Comments

At one point in time mechanical seven segment displays were ubiquitous, over time many places have replaced them with other types of displays. [Sebastian] has a soft spot for these old mechanically actuated displays and has built an open-source 7-segment display with some very nice features.

We’ve seen a good number of DIY 7-segment displays on this site before, the way [Sebastian] went about it resulted in a beautiful well thought out result. The case is 3D printed, and although there are two colors used it doesn’t require a multicolor 3d printer to make your own. The real magic in this build revolves around the custom PCB he designed. Instead of using a separate electromagnets to move each flap, the PCB has coil traces used to toggle the flaps. The smart placement of a few small screws allows the small magnets in each flap to hold the flap in that position even when the coils are off, greatly cutting down the power needed for this display. He also used a modular design where one block has the ESP32 and RTC, but for the additional blocks those components can remain unpopulated.

The work he put into this project didn’t stop at the hardware, the software also has a great number of thoughtful features. The ESP32 running the display hosts a website which allows you to configure some of the many features: the real-time clock, MQTT support, timer, custom API functions, firmware updates. The end result is a highly customizable, display that sounds awesome every time it updates. Be sure to check out the video below as well as his site to see this awesome display in action. Also check out some of the other 7-segment displays we’ve featured before.

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A green box with the answer to if a nuke has gone off with red neon lights

Has A Nuke Gone Off? Indicator

June 22, 2025 by Ian Bos 23 Comments

Look out of a window, ask yourself the question, “Has a nuke gone off?”. Maybe, maybe not, and all of us here at Hackaday need to know the answer to these important questions! Introducing the hasanukegoneoff.com Indicator from [bigcrimping] to answer our cries.

An ESP32 running a MicroPython script handles the critical checks from hasanukegoneoff.com for any notification of nuclear mayhem. This will either power the INS-1 neon bulb, indicating “no” or “yes” in the unfortunate case of a blast. Of course, there is also the button required for testing the notification lights; no chance of failure can be left. All of this is fitted onto a custom dual-sided PCB and placed inside a custom 3D-printed enclosure.

Hasanukegoneoff.com’s detection system, covered before here, relies on an HSN-1000L Nuclear Event Detector to check for neutrons coming from the blast zone. [bigcrimping] also provides the project plans for your own blast detector to answer the critical question of “has a nuke gone off” from anywhere other than the website’s Chippenham, England location.

This entire project is open sourced, so keep sure to check out [bigcrimping]’s GitHub for both portions of this project on the detector and receiver. While this project provides some needed dark humor, nukes are still scary and especially so when disarming them with nothing but a hacksaw and testing equipment.

Thanks to [Daniel Gooch] for the tip.

ESP32 Dashboard Is A Great Way To Stay Informed

June 18, 2025 by Jenny List 3 Comments

The original ESP32 may be a little long in the tooth by now, but it remains a potent tool for connected devices. We were drawn to [Max Pflaum]’s ESP32 Dashboard as a great example, it’s an ESP32 hooked up to an e-paper display. The hardware is simple enough, but the software is what makes it interesting.

This is deigned as a configurable notification tool, so to make it bend to the user’s will a series of widgets can be loaded onto it. The device runs MicroPython, making it easy enough to write more than the ones already on place. The screen is divided into four zones, allowing for a range of widgets to be used at once. All the details can be found in a GitHub repository.

We like it for its configurability and ease of programming, and because it delivers well on the promise of a useful device. An ESP32 and e-ink combination with MicroPython apps is something we’ve seen before in the world of badges.

Supercon 2024: Repurposing ESP32 Based Commercial Products

June 10, 2025 by Lewin Day 4 Comments

It’s easy to think of commercial products as black boxes, built with proprietary hardware that’s locked down from the factory. However, that’s not always the case. A great many companies are now turning out commercial products that rely on the very same microcontrollers that hackers and makers use on the regular, making them far more accessible for the end user to peek inside and poke around a bit.

Jim Scarletta has been doing just that with a wide variety of off-the-shelf gear. He came down to the 2024 Hackaday Superconference to tell us all about how you can repurpose ESP32-based commercial products.

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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.
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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.

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The bill of materials and the assembled smartwatch.

Piko, Your ESP32 Powered Fitness Buddy

June 5, 2025 by John Elliot V 3 Comments

Over on Hackaday.io there’s a fun and playful write-up for a fun and playful project — the Piko, an ESP32 powered smartwatch.

Our hackers [Iloke Alusala], [Lulama Lingela], and [Rafael Cardoso] teamed up to design and manufacture this wrist-worn fitness wearable. Made from an ESP32 Beetle C6 and using an attached accelerometer with simple thresholds the Piko can detect if you’re idle, walking, jogging, or sprinting; and at the same time count your steps.

The team 3D printed the requisite parts in PLA using the printer in their university makerspace. In addition to the ESP32 and printed parts, the bill of materials includes a 240×240 IPS TFT LCD display, a LIS331HH triple-axis accelerometer, a 200 mAh battery, and of course, a watch strap.

Demonstrating splendid attention to detail, and inspired by the aesthetic of the Tamagotchi and pixel art, the Piko mimics your current activity with a delightful array of hand-drawn animations on its display. Should you want to bring a similar charm to your own projects, all the source is available under the MIT license.

If you’re interested in smartwatch technology be sure to check out our recent articles: Smartwatches Could Flatten The Curve Of The Next Pandemic and Custom Smartwatch Makes Diabetes Monitoring Easier For Kids.

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