ESP32

817 Articles

ESP-SDR Can Now Transmit

October 13, 2026 by 24 Comments

Well, that was fast! Last week, we reported on two apparently simultaneous hacks using the 2.4 GHz radio inside many ESP32 variants that enabled raw access to the radio samples, turning it into a listen-only software defined radio (SDR) platform. Listen only? That’s only half of the SDR story.

Last weekend, [marble] got started fixing that, and released an early early version of ESP32 firmware that can also transmit, and got it working with gqrx. The demo communicates between an S3 and a C6 using a Hellschreiber mode, something that’s certainly out of the WiFi spec. And it didn’t stop there, either. [marble] is working on 802.15.4 modulation at the moment, which means that maybe soon your ESP32 will speak ZigBee.

This is all in the roughly 2.4 GHz band, but [marble] suggests that it might be good down to 1.8 GHz. (Editor’s note: previously, we said 100 MHz, but that was incorrect.) So there is still some uncharted terrain, and it’s clear that the boundaries on the ESP-SDR are just starting to get pushed.

If the early hacks on the RTL-SDR set off a wave of hacker SDR radio experimentation, and we can only hope that this is the beginning of the ESP-SDR era. Thanks then to [marble]– and the original hacks coming from the Espargos team for kicking this all off!

ESP32 As Your Raspberry Pi’s Linux Wireless Co-processor

October 7, 2026 by 12 Comments

A laptop with no wireless connectivity feels like a rarity – but when you shop for powerful Linux single-board computers (SBCs), it is pretty common to see one skimp on WiFi. At the same time, current wireless cards can leave much to be desired. A mess of proprietary firmware, ephemeral or even binary blob drivers, weird glitches never resolved, and sometimes entirely source-less blobs with an expiration date. Maybe the SBC doesn’t have a free USB port for a plug-and-play WiFi chip, or you don’t want to design for an obscure hard-to-source castellated module.

What if I told you there’s a unique solution to the problem, as long as the SBC has an SDIO or SPI to spare? There’s a wireless card we can all try to get behind, and it’s certainly not flawless but gives us way more room to grow – it’s got somewhat open-source firmware, it comes from a respectable company, and it’s nigh-guaranteed to be easy to source. I am, of course, talking about esp-hosted – using ESP32 modules as your WiFi/BT card, over SDIO or SPI.

I’ve recently added an ESP32-C6 into my project, and setting up esp-hosted wasn’t ultra straightforward – so here’s a guide, and a discussion on what makes esp-hosted so cool and so incredibly promising. Spoilers: it works with privacy switches that cut out power, it could be hacked into a coprocessor for mesh protocols, and it could potentially help us build a fully open-source SDIO WiFi card.

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Two Microcontrollers Talking, All It Needs Is An LED

October 5, 2026 by 10 Comments

There are some projects that seem at first sight to be easy, but anyone who tries them finds a whole heap of unexpected problems and turns to the off-the-shelf device. PCB antennas for example, or data links using LEDs, whether IR or visible. The latter doesn’t faze [Luca Soltoggio] though, because he has two ESP32s talking to each other using visible light. Best of all, both use a single LED as both transmitter and receiver.

The software is called SecurePair, and is an Arduino library for exchanging keys and communicating with encryption. The LEDs are the cool hardware hack but it’s designed to work with ESPNow or LoRa too, indeed a typical use case would see light for pairing and wireless for the exchange of encrypted data.. In case you were wondering, it relies on the property of an LED that it’s also a photodiode of sorts. Best of all, while the examples have two ESP32s, it’s not limited to that number and many more can join the conversation if needed.

Check out the video below to see it in action — if you’re curious about LEDs as sensors, we’ve been there too.

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The ESP32, An SDR In Itself

October 3, 2026 by 38 Comments

Perhaps the most famous of all the software-defined radio (SDR) receivers is the RTL-SDR, a digital TV receiver on which an undocumented feature was found. Perhaps other radio-enabled chips also have the same undocumented feature? It seems in the case of some members of the ESP32 family, they do. It’s a discovery made independently in two places, by Espargos, and a Reddit user by the name of h0m3us3r.

What’s happening is that the undocumented mode taps the I/Q stream off before the WiFi modem, and this can be read and processed by SDR software on an external computer. The undocumented mode can be found on ESP32 chips with the earlier Tensilica hardware onwards, so the low power Bluetooth only chips or the non-radio-equipped P4 won’t work. Sadly it’s also only possible with the receive side, with both 2.4 and 5 GHz bands being supported depending on the microcontroller in question.

This isn’t quite the general purpose SDR we got with the RTL-SDR, but there are still plenty of uses to which it can be put. We’re curious as to whether someone can implement the software side of an SDR on the same chip, but we are guessing that might be beyond their capabilities. Either way, we’re looking forward to what the community does with this new-found knowledge.

Elgato Key Lights Get Matter Upgrade

October 1, 2026 by 3 Comments

[Michael H Thiesen] had a couple of Elgato Key Lights in his home streaming setup. The only problem was that they would stop responding regularly, requiring a power cycle to get them going again. He never quite pinned down where the problem lay; instead, he set about replacing the light controllers wholesale to provide more reliable functionality.

In place of the original controllers, a pair of ESP32-C3 boards were substituted in. The original design simply had a Realtek controller chip wired into a PCA9635 LED controller, so the swap was as easy as plucking one out and wiring the new microcontroller in its place. The capable ESP32-C3 offers native Matter support, which enabled the new controllers to join [Michael’s] Apple Home setup natively. Running a firmware coded in Rust, the controllers offer power, brightness, and colour-temperature control right in Apple Home. As a bonus, there was no need to use Homebridge to get the lights hooked up to the smarthome setup anymore, eliminating a dependency and a possible source of occasional failures.

Design files are on Github for the curious. We’ve featured other great Elgato hacks before, too, like this nifty capture card firmware hack. If you’re tinkering with your own smarthome hacks, be sure to let us know on the tipsline.

The Whole Computer Is Vim

October 1, 2026 by 42 Comments

Love it or hate it, Vim, the vi-compatible minimalist editor, is a common denominator between a huge array of operating systems. If you need to edit a file, it’s usually safe to expect it there if your normal editor is absent. Now thanks to [Omwah] it’s moved onto the most meager of platforms, where it becomes the firmware itself rather than a program running on an OS.

ESP-Vim is, as its name suggests, Vim, for some of the ESP32 series of microcontrollers. It boots straight into the familiar editor on an attached screen, and it has filesystem and git access, along with MicroPython. It’s a small computer for working with text files and some basic scripting, and we like the idea.

It needs a board with an ESP32-S3 or P4, with 16 MB of Flash and at least 8 MB of PSRAM. There’s a list of boards that meet this spec, and we can’t help noticing that one of them is the version of the Cheap Yellow Display that comes with an S3. Hook up a Bluetooth keyboard and you’re in.

How easy it will be to use remains to be seen, but bearing in mind that the vi interface followed by Vim was designed for very slow terminals in a much earlier decade, and it could be just right for these platforms. Would you use one?

Vim logo: The Vim project, VIM License.

An IR Blaster Project, In A Nutshell

September 28, 2026 by 33 Comments

The speed that computers have gotten smaller is a bit mind-bending. Most of us now walk around with computers in our pockets that would have rivaled the supercomputers from a few decades ago. And, although it seems like the speed at which things are getting smaller and faster has slowed a bit compared to the rapid pace of the 90s and 00s, some truly minuscule computers are accessible nowadays. So much so that it’s possible to do useful computing inside a walnut shell.

The first step in this build is to crack into a walnut. Most have a natural seam that separates two hemispheres, so splitting it open, enjoying a small snack, and then adding some small neodymium magnets on the inside of that seam to close up the shell is not too difficult. From there, some LEDs were installed at various points in the shell, with an ESP32-C3 installed in the middle to control everything and oriented so that its USB port is still accessible.

Although putting a small microcontroller in a nutshell might seem like a novelty, [JSK-koubou] is actually using the LEDs to perform a useful task. The walnut sits in his living room and connects to a home automation system through the ESP32, and when it receives a command it uses the LEDs to send infrared signals to non-connected devices. Hiding projects in unexpected places is a fun pastime, like this Meshtastic node hidden in a landscape light.

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