ESP32

698 Articles

A circuit sculpture designed to help you sleep.

Sweet Sound Sculpture Helps You Sleep Soundly

November 21, 2025 by 9 Comments

Have trouble sleeping, or getting to sleep in the first place? You’ve no doubt heard of white noise machines, but know it would be much cooler to make your own. Enter Noise Maker, a DIY sound sculpture by [optimus103733], who wanted to learn something in the process of creating.

The best thing about this sound sculpture aside from the looks is that you can not only play five different sounds (e.g. birds, traffic, water, frog, white noise), you can mix them together into a rich but relaxing cacophony.

As you can probably see from the picture, Noise Maker is based on the ESP32 and uses an SD card module, an amplifier, and five six pots. Be sure to check out the pictures, because there are three layers of copper connections and a lot of careful bending to make it all come together. In the video after the break, you can hear it in action.

It seems [optimus103733] isn’t completely satisfied and wants to make a few improvements in the future, such as a voltage regulator, a power switch, and a timer to automatically stop playback once (we assume) sleep has come. Evidently the ESP32 struggles a little with mixing six audio sources, but hey, lesson learned.

Wait, why do we sleep in the first place?

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Building A Smart Speaker Outside The Corporate Cloud

November 17, 2025 by 15 Comments

If you’re not worried about corporate surveillance bots scraping your shopping list and manipulating you through marketing, you can buy any number of off-the-shelf smart speakers for your home. Alternatively, you can roll your own like [arpy8] did, and keep your life a little more private.

The build is based around an ESP32 microcontroller. It connects to the ‘net via its inbuilt Wi-Fi connection, and listens out for your voice with an INMP441 omnidirectional microphone module. The audio data is trucked off to a backend server running a Whisper speech-to-text model. The text is then passed to Google’s Gemini 2.5 Flash large language model. The response generated is passed to the Piper Neural Voice text-to-speech engine, sent back to the ESP32, and spat out via the device’s DAC output and a speaker attached to an LM386 amplifier. Basically, anything you could ask Gemini, you can do with this device.

By virtue of using a commercial large language model, it’s not perfectly private by any means. Still, it’s at least a little farther removed than using a smart speaker that’s directly logged in to your Amazon/Google/Hulu/Beanstikk account. Files are on Github for those eager to dive into the code. We’ve seen some other fun builds along these lines before, too. Video after the break.

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Cheap Multimeter Gets Webified

November 12, 2025 by 14 Comments

[Mellow Labs] wanted to grab a multimeter that could do Bluetooth. Those are cheap and plentiful, but the Bluetooth software was, unsurprisingly, somewhat lacking. A teardown shows a stock Bluetooth module. A quick search found a GitHub with software. But then he had a fiendish idea: could you replace the Bluetooth module with an ESP32 and use WiFi instead of Bluetooth?

This was as good an excuse as any to buy a cheap logic analyzer. Armed with some logic captures, it was easy to figure out how to fake the meter into thinking a Bluetooth client was connected.

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An Audio Brick For Your Smart Home

November 1, 2025 by 38 Comments

If you’ve ever wanted to pump sound to all the rooms of your house, you might use any one of a number of commercial solutions. Or, you could go the more DIY route and whip up something like the Esparagus Audio Brick built by [Andriy]. 

The concept is simple—it’s a small unit, roughly the size of a brick, which streams high-quality audio. It’s based around an ESP32, which pulls in digital audio over Wi-Fi or Ethernet. The microcontroller is hooked up to a TAS5825M DAC, which comes with a built-in amplifier for convenience. The Esparagus is designed for integration with Home Assistant, allowing for easy control as part of a smart home setup. It’s also compatible with Spotify Connect, AirPlay, and Snapcast—the latter of which provides excellent sync when using multiple units across several rooms.

Design files are available on Github for the curious. We’ve seen other neat projects in this space, before, too—like the charmingly-named OtterCast. Video after the break.

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Volumetric Display Takes A Straight Forward (and Backward) Approach

November 1, 2025 by 11 Comments

There’s something delightfully sci-fi about any kind of volumetric display. Sure, you know it’s not really a hologram, and Princess Leia isn’t about to pop out and tell you you’re her only hope, but nothing says “this is the future” like an image floating before you in 3D. [Matthew Lim] has put together an interesting one, using persistence-of-vision and linear motion.

The basic concept is so simple we’re kind of surprised we don’t see it more often. Usually, POV displays use rotary motion: on a fan, a globe, a disk, or even a drone, we’ve seen all sorts of spinning LEDs tricking the brain into thinking there’s an image to be seen. [Matthew’s] is apparently the kind of guy who sticks to the straight-and-narrow, on the other hand, because his POV display uses linear motion.

An ESP32-equipped LED matrix module is bounced up by an ordinary N20 motor that’s equipped with an encoder and driven by a DRV8388. Using an encoder and the motor driver makes sure that the pixels on the LED matrix are synced perfectly to the up-and-down motion, allowing for volumetric effects. This seems like a great technique, since it eliminates the need for slip rings you might have with rotary POV displays. It does of course introduce its own challenges, given that inertia is a thing, but I think we can agree the result speaks for itself.

One interesting design choice is that the display is moved by a simple rack-and-pinion, requiring the motor to reverse 16 times per second. We wonder if a crank wouldn’t be easier on the hardware. Software too, since [matthew] has to calibrate for backlash in the gear train. In any case, the stroke length of 20 mm creates a cubical display since the matrix is itself 20 mm x 20 mm. (That’s just over 3/4″, or about twice the with of a french fry.) In that 20 mm, he can fit eight layers, so not a great resolution on the Z-axis but enough for us to call it “volumetric” for sure. A faster stroke is possible, but it both reduces the height of the display and increases wear on the components, which are mostly 3D printed, after all.

It’s certainly an interesting technique, and the speechless (all subtitles) video is worth watching– at least the first 10 seconds so you can see this thing in action.

Thanks to [carl] for the tip. If a cool project persists in your vision, do please let us know. Continue reading “Volumetric Display Takes A Straight Forward (and Backward) Approach” →

Building A Clamshell Writer Deck

October 31, 2025 by 10 Comments

Most of us do our writing on computers these days, but the modern computing environment does present a lot of distractions. That’s let to the concept of the writer deck, a simplified device intended more specifically for word processing tasks. [Ashtf] has built a great example of the form with a modified version of the PocketMage device.

The PocketMage is a clamshell PDA device that [Ashtf] has been working on for some time. It’s powered by an ESP32, hooked up to a nice e-ink display. In its basic form, it’s not the ideal device for doing serious writing work, mostly because of its tiny keyboard. However, [Ashtf] has since added external keyboard support, which completely changes the game. With the use of a small USB C to USB A adapter, you can hook up any conventional USB keyboard that you like to best attain your maximum typing speed.

The result is a compact, simple device that lets you type away without distractions. If your latest fanfic isn’t coming along quickly enough because you keep losing focus to social media, perhaps this is a route you might like to go. [Ashtf] also included Markdown support so you can create richer documents on the device while operating in what is still fundamentally a text-only environment.

It’s neat to build custom devices that suit your own personal productivity needs. If you dig the PocketMage, you might like to check out the design files on Github. We’ve featured some other fun writer decks before, too. Video after the break.

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HRV Gets Home Automation Upgrades

October 26, 2025 by 5 Comments

In our modern semi-dystopia, it seems like most companies add automation features to their products to lock them down and get consumers to buy even more proprietary, locked-down components. The few things that are still user-upgradable are getting fewer and farther between, but there are still a few things that can be modified and improved to our own liking like this control panel for a heat recovery ventilator (HRV).

HRVs are systems that exchange fresh, outside air with stale, inside air while passing them both through a heat exchanger to keep from wasting energy. Many systems run continuously but they aren’t always needed, so some automation is beneficial. This upgrade from [vincentmakes] improves the default display for a Zehnder Comfoair Q350 HRV with a color display as well as adding it in to a home automation system, letting a user control fan speeds remotely as well as alerting the user when it’s time for filter replacements and providing up-to-date information from all the sensors in the HRV.

The project builds on a previous project which adapted an ESP32 to interact with the CAN bus used on these devices. With these upgrades the user can forgo the $300 proprietary upgrade that would be needed to get the same functionality otherwise. It’s also fully open-source so all that’s needed is to flash the firmware, replace the display, and enjoy the fresh air. There’s other modern HVAC equipment that can benefit from new controllers and a bit of automation as well.

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