ESP32

683 Articles

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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Off To The Races With ESP32 And EInk

September 15, 2025 by 16 Comments

Off to the races? Formula One races, that is. This project by [mazur8888] uses an ESP32 to keep track of the sport, and display a “live” dashboard on a 2.9″ tri-color LCD.

“Live” is in scare quotes because updates are fetched only every 30 minutes; letting the ESP32 sleep the rest of the time gives the tiny desk gadget a smaller energy footprint. Usually that’s to increase battery life, but this version of the project does not appear to be battery-powered. Here the data being fetched is about overall team rankings, upcoming races, and during a race the current occupant of the pole-position.

There’s more than just the eInk display running on the ESP32; as with many projects these days, micro-controller is being pressed into service as a web server to host a full dashboard that gives extra information as well as settings and OTA updates. The screen and dev board sit inside a conventional 3D-printed case.

Normally when talking Formula One, we’re looking into the hacks race teams make. This hack might not do anything revolutionary to track the racers, but it does show a nice use for a small e-ink module that isn’t another weather display. The project is open source under a GPL3.0 license with code and STLs available on GitHub.

Thanks to [mazur8888]. If you’ve got something on the go with an e-ink display (or anything else) send your electrophoretic hacks in to our tips line; we’d love to hear from you.

From Paper To Pixels: A DIY Digital Barograph

September 14, 2025 by 6 Comments

A barograph is a device that graphs a barometer’s readings over time, revealing trends that can predict whether stormy weather is approaching or sunny skies are on the way. This DIY Digital Barograph, created by [mircmk], offers a modern twist on a classic technology.

Dating back to the mid-1700s, barographs have traditionally used an aneroid cell to move a scribe across paper that advances with time, graphing pressure trends. However, this method has its shortcomings: you must replace the paper once it runs through its time range, and mechanical components require regular maintenance.

[mircmk]’s DIY Digital Barograph ditches paper and aneroids for a sleek 128×64 LCD display that shows measurements from a BME280 pressure sensor. Powered by an ESP32 microcontroller — the code for which is available on the project page — the device checks the sensor upon boot and features external buttons to cycle through readings from the current moment, the last hour, or three hours ago. Unlike traditional barographs that only track pressure, the BME280 also measures temperature and humidity, which are displayed on the screen for a more complete environmental snapshot.

Head over to the project’s Hackaday.io page for more details and to start building your own. Thanks to [mircmk] for sharing this project! We’re excited to see what you come up with next. If you’re inspired, check out other weather display projects we’ve featured.

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Build Your Own Pip-Boy Styled Watch

September 2, 2025 by 6 Comments

[Arnov Sharma]’s latest PIP-WATCH version is an homage to Pip-Boys, the multi-function wrist-mounted personal computers of Fallout.

We like the magnetic clasp on the back end.

[Arnov] has created a really clean wearable design with great build instructions, so anyone who wants to make their own should have an easy time. Prefer to put your own spin on it, or feel inspired by the wrist-mounted enclosure? He’s thoughtfully provided the CAD files as well.

Inside the PIP-WATCH is a neat piece of hardware, the Lilygo T-Display-S3 Long. It’s an ESP32-based board with a wide, touch-enabled, color 180 x 640 display attached. That makes it a perfect fit for a project like this, at least in theory. In practice, [Arnov] found the documentation extremely lacking which made the hardware difficult to use, but he provides code and instructions so there’s no need to go through the same hassles he did.

In addition to the Hackaday.io project page, there’s an Instructables walkthrough.

If you put your own spin on a Pip-boy (whether just a project inspired by one, or a no-detail-spared build of dizzying detail) we want to hear about it, so be sure to drop us a tip!

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A Label Printer Gets A New Brain

September 1, 2025 by 9 Comments

The internals of a printer, whatever technology it may use, are invariably proprietary, with an abstracted more standard language being used to communicate with a host computer. Thus it’s surprisingly rare to see hacks on printers as printers, rather than printer hacks using the parts for some other purpose. This makes [Oelison]’s brain-swap of a Casio thermal label printer a welcome surprise, as it puts an ESP32 in the machine instead of whatever Casio gave it.

The value in the hack lies in the insight it gives into how a thermal printer works as much as it does in the ESP32 and the Casio, as it goes into some detail on the various signals involved. The strobe line for instance to enable the heater is a nuance we were unaware of. The resulting printer will lose its keyboard and display, but  make up for it in connectivity.

Despite what we said earlier this isn’t the first label printer hack we’ve seen. A previous one was Linux-based though.

Automated Brewing

August 26, 2025 by 6 Comments

There’s little more to making alcoholic beverages than sugar, water, yeast, and time. Of course those with more refined or less utilitarian tastes may want to invest a bit more care and effort into making their concoctions. For beer making especially this can be a very involved task, but [Fieldman] has come up with a machine that helps automate the process and take away some of the tedium.

[Fieldman] has been making beers in relatively small eight-liter batches for a while now, and although it’s smaller than a lot of home brewers, it lends itself perfectly to automation. Rather than use a gas stove for a larger boil this process is done on a large hot plate, which is much more easily controlled by a microcontroller. The system uses an ESP32 for temperature control, and it also runs a paddle stirrer and controls a screen which lets the brewer know when it’s time to add ingredients or take the next step in the process. Various beers can be programmed in, and the touchscreen makes it easy to know at a glance what’s going on.

For a setup of this size this is a perfect way to take away some of the hassle of beer brewing like making sure the stove didn’t accidentally get too hot or making sure it’s adequately stirred for the large number of hours it might take to brew, but it still leaves the brewer in charge for the important steps.

Beer brewing is a hobby with a lot of rabbit holes to jump down, and it can get as complicated as you like. Just take a look at this larger brewery setup that automates more tasks on a much larger scale.

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