ESP32

688 Articles

Divining Air Quality With A Cheap Computer Vision Device

October 5, 2025 by 10 Comments

There are all kinds of air quality sensors on the market that rely on all kinds of electro-physical effects to detect gases or contaminants and report them back as a value. [lucascreator] has instead been investigating a method of determining air quality that is closer to divination than measurement—using computer vision and a trained AI model.

The system relies on an Unihiker K10—a microcontroller module based around the ESP32-S3 at heart. The chip is running a lightweight convolutional neural network (CNN) trained on 12,000 images of the sky. These images were sourced from a public dataset; they were taken in India and Nepal, and tagged with the relevant Air Quality Index at the time of capture. [lucascreator] used this data to train their model to look at an image taken with a camera attached to the ESP32 and estimate the air quality index based on what it has seen in that existing dataset.

It might sound like a spurious concept, but it does have some value. [lucascreator] cites studies where video data was used for low-cost air quality estimation—not as a replacement for proper measurement, but as an additional data point that could be sourced from existing surveillance infrastructure. Performance of such models has, in some cases, been remarkably accurate.

[lucascreator] is pragmatic about the limitations of their implementation of this concept, noting that their very compact model didn’t always perform the best in terms of determining actual air quality. The concept may have some value, but implementing it on an ESP32 isn’t so easy if you’re looking for supreme accuracy. We’ve featured some other great air quality projects before, though, if you’re looking for other ways to capture this information. Video after the break.

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Building A Desk Display For Time And Weather Data

October 2, 2025 by 19 Comments

Just about every laptop, desktop, and smartphone in your life can tell you the date, time, and current weather predictions. However, sometimes it’s nice to have simple data displayed on a bespoke device. That’s what inspired [Mario] to create ESPTimeCast. 

As you might have guessed by the name, the project is designed around the ESP32 and ESP8266 microcontrollers; either one is up to the task of running the show here. Both come with Wi-Fi connectivity out of the box, which makes it easy for them to hook up to the Internet to query NTP servers for the time and weather data from OpenWeatherMap. The data is then displayed on an LED matrix display, made up of four 8×8 LED modules and driven with the aid of the MAX7219 IC. Configuration is handled over a simple web interface hosted on the device itself. All the parts are wrapped up in a 3D-printed housing that would be very fitting in any home that appreciates the magic of late 60s/early 70s decor.

Hackers love building clocks, weather stations, and other useful information displays. We’ve seen a great many examples over the years. If you’re cooking up your own neat project in this area, don’t hesitate to let us know!

Hard Hat Becomes Bluetooth Direction Finder

September 30, 2025 by 10 Comments

Have you ever wanted to find a Bluetooth device out in the wild while looking like the comic relief character from a science-fiction series? You might like Dendrite, the direction-finding hat from [SolidStat3].

Dendrite is intended for hunting down Bluetooth devices. It’s capable of direction estimation based on signal strength readings from four ESP32 microcontrollers mounted on an off-the-shelf hard hat. Each ESP32 searches for BLE devices in the immediate area and reports the apparent signal strength to a fifth ESP32, which collates readings from all units. It then runs a simple multilateration algorithm to estimate the direction of the device. This information is then displayed via a ring of addressable LEDs around the perimeter of the hat. White LEDs marking the direction of the detected device. The only problem? You can’t see the LEDs while you’re wearing the hat. You might need a friend to help you… or you can simply take it off to see what it’s doing.

Ultimately, this project is a useful direction-finding hard hat that would also make a perfect prop from an episode of Inspector Spacetime. We’ve covered direction finding in other contexts before, too. Meanwhile, if you’re cooking up your own innovative hard hat (or radio) hacks, don’t hesitate to let us know!

Smart Home Gets A Custom Keypad Controller

September 28, 2025 by 3 Comments

Voice assistants and smartphones are often the go-to interfaces for modern smart home systems. However, if you fancy more direct physical controls, you can go that route as well. To that end, [Salim Benbouziyane] whipped up a nifty keypad to work with his Home Assistant setup.

The build is based on an ESP32 microcontroller, which has wireless hardware onboard to communicate with the rest of [Salim’s] Home Assistant setup. Using the ESPHome firmware framework as a base, the microcontroller is connected to a four-by-three button keypad array, built using nice clicky key switches. There’s also an indicator light on top as a system status indicator. A fingerprint scanner provides an easy way for users to authenticate when disarming the alarm.

Security and speed were the push for [Salim] to whip up this system. He found it difficult to disarm his alarm in a hurry when fumbling with his phone, and the direct keypad entry method was far more desirable.

Sometimes, the easiest route to the smart home of your dreams is to just build the exact solutions you need. Video after the break.

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Bringing Bluetooth To The Zune

September 27, 2025 by 10 Comments

The Zune might have joined the portable media player game too late to ever really be competition for the iPod, but that doesn’t mean it didn’t pick up some devoted fans along the way. Some of them are still breathing new life into the device, such as [The Director of Legal Evil Emeritus] at the Louisville Hackerspace, with this project that gives it Bluetooth capability.

As far as media players go, there’s still some solid reasons to rock a Zune. Compared to other devices of the era, it offers a better DAC, an FM tuner, and no iTunes reliance. The goal of this project was to bring a bit of modern functionality without having to do any modification of the Zune itself. As the player supported docks with IR remotes, this build involves using an ESP32 to listen to the Bluetooth signal coming from the speakers, interpret any button presses, and forward them along to the Zune’s dock.

There is a dedicated scene for these old music players, but this build is unique for not needing to crack open the case and splice in a Bluetooth module. Even then, those typically don’t have the ability to interact with things like this speaker with its integrated control buttons.

We don’t often seen Zune hacks come our way — the last time Microsoft’s player graced these pages was in 2010, when the Open Zune Development Kit was released.

Thanks to [JAC_101] for the tip!

Heart Rate Measurement Via WiFi, The DIY Way

September 23, 2025 by 13 Comments

A few weeks back, we reported on a research group that figured out how to measure heartrate using perturbations in WiFi signals. [Nick Bild] was interested in this so-called “Pulse-Fi” technique, but noted the paper explaining it was behind a paywall. Thus, he worked to recreate the technology himself so he could publish the results openly for anyone eager to learn.

[Nick] paid for the research paper, and noted that it was short on a few of the finer details and didn’t come with any code or data from the original research team. He thus was left to figure out the finer details of how to measure heart rate via WiFi in his own way, though he believes his method is quite close to the original work.

The basic concept is simple enough. One ESP32 is set up to transmit a stream of Channel State Information packets to another ESP32, with a person standing in between. As the person’s heart beats, it changes the way the radio waves propagate from the transmitting unit to the receiver. These changes can be read from the packets, and processed to estimate the person’s heart rate. [Nick] explains the various data-massaging steps involved to go from this raw radio data to a usable heart rate readout.

It’s a great effort from [Nick] to recreate this research all on his own in his home lab. Files are on GitHub for the curious. If you’re eager to learn more about these innovative measurement techniques, you might like to read our prior reporting on the tech. Also, it’s worth remembering—don’t use your homebrew prototypes for any serious healthcare purposes. Continue reading “Heart Rate Measurement Via WiFi, The DIY Way” →

For A Robot Claw, The Eyes Have It

September 21, 2025 by 3 Comments

Have you ever wished your hand had an extra feature? Like, maybe, a second thumb? A scope probe pinky maybe? Well, if you are building a robot effector, you get to pick what extra features it has. [Gokux] has the aptly named Cam Claw, which is a 3D printed claw with a built-in camera so you can see exactly what it is doing.

The brains are an ESP32-S3 and the eyes — well, the eye technically — uses an OV3660 camera. There’s even a light in case you are in a dark space. A servo drives it, and the printed gear train is pretty fun to watch, as you can see in the video below.

This project is all about the mechanics. The electronic hardware is trivial. A battery, a power controller, and a servo complement the ESP32 and camera. Six LEDs for light, and the job is done.

Obviously, the gripping power will only be as good as the servo. However, we really liked the idea of putting eyes on a robot hand where they count. Of course, the claw you really want a camera on is in the arcade. We’d like to see cameras on some other robot appendages.

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