A Smart Alarm Clock That Doesn’t Sell Your Soul

November 8, 2026 by Tom Nardi 17 Comments

Devices from the likes of Google and Amazon can be used as high-tech alarm clocks that can show the weather and family photos in addition to telling you what time it is. But they’re also used to push ads out and potentially do other shady things that you’d probably just as soon not have in your bedroom.

If you like the features offered by devices like these but not the hidden costs that come with them, take a look at Rouse. This firmware, which can be installed on common ESP32 development boards such as the Waveshare ESP32-S3-Touch and the ubiquitous Cheap Yellow Display, provides some of those same features in a DIY package.

There’s no user account, no subscription, and no app for your phone that will inevitably stop working some day. The firmware offers up a web interface for configuration that can be accessed by anything with a web browser, and while it can perform firmware updates over the network, it only does so with your approval. It might seem odd that we have to double check to make sure our alarm clocks aren’t leaking any of our information onto the Internet, but that’s the world we live in apparently.

In addition to the basic ESP32 board, you’ll probably want to add some buttons and a speaker, all of which is documented in a fantastic build guide. There’s even files for you to 3D print your own enclosure for the finished clock, though you could certainly put it in an enclosure of your own choosing should you want to customize the build further.

Hackers and makers love clock projects, and at this point we’ve covered more than we can even keep track of. As part of that we’ve seen a number of alarm clocks builds, but as is so often the case around these parts, they tend to be one-off builds. The fact that Rouse has been built with community in mind really makes it stand out, and we’d love to hear in the comments if any of you already have one of these ticking away on your nightstand.

Proper Linux, On An ESP32

November 7, 2026 by Jenny List 37 Comments

The ESP32 series of microcontrollers feature a lot on these pages, offering as they do a significantly powerful processor and in most cases, wireless connectivity. One recent member of the bewilderingly large family is the ESP32-S31, It’s a dual-core RISC-V unit with WiFi 6, and if that’s not interesting enough there’s the news that it runs Linux. Not -nommu Linux, but the full-fat version, as it has a memory management unit.

Before you imagine a superlative experience, it’s worth the reminder that the available resources will not give it much when it comes to computing power. But there’s an Espressif GitHub repository, and work on a port of a 6.x kernel, so you should be able to do something with it. A quick look on AliExpress finds dev boards at a range of prices, so the cost of experimenting shouldn’t be too high.

This moment at which the paths of microcontroller and full-fat SoC start to cross has been on the horizon for quite a while, and it’s exciting to see it finally arrive. Expect more similar chips in competition with this one, and more power too. Meanwhile see our noting the launch of the S31.

The Hidden Microcontroller Inside A LoRa Chip

November 7, 2026 by Jenny List 15 Comments

If you’ve ever done anything with LoRa, the chances are you’ve used a LoRa chip or module as a peripheral for a microcontroller, and left it at that. But that’s not always the case. Rather than being a pre-programmed ASIC under the hood, the Semtech LR2021 has its own on-board microcontroller whose firmware can be updated. [Alex Beale] has managed to unlock its secrets.

The use of LLMs can elicit strong opinions at times, but in this case we agree with him that the task of reverse engineering this hidden microcontoller would have been a near-impossible task without their help. Having done so though,he can write custom firmwares, which he’s able to demonstrate. Running the required FFTs for a waterfall display on-chip for example is now possible, as is running your mesh network node on the chip itself.

This work continues a streak of recent discoveries unlocking software-defined radio functionality inside dedicated radio chips, with both WiFi and LoRa chips falling prey to reverse engineering. It’s an interesting time, if SDR is your thing.

Thanks [Notbasa] for the tip.

ToothPaste Goes Where Your Password Manager Doesn’t

November 3, 2026 by Bryan Cockfield 21 Comments

One of the easiest ways of improving security and privacy when using the Internet, and computers in general, is to use strong passwords unique to each site or service. A password manager makes this easy on your phone or computer, but what if you’re in a situation where you can’t install any software on the device you’re logging into? In that case, maybe it’s time to get out the Toothpaste.

The way this creation from [brisk4t] works is that an ESP32-S3 is programmed to act as a keyboard and mouse for any computer it’s plugged into. From there, it connects over an encrypted WEB-BLE connection to another device like a laptop or smartphone. This second device can send text to the ESP32 acting using an extension for Chromium-based browsers, and the ESP32 sends it over the USB connection as if it were nothing more than a standard keyboard. This is all done without having to install any apps or drivers on the target machine, since any machine in the last two or three decades can recognize a USB keyboard and mouse with no problem.

Not only does this allow for easy password input for awkward situations, this can also be used for BIOS where an app couldn’t be installed anyway, for air-gapped systems with no networking, or insecure systems the user doesn’t trust. If you don’t need quite as many bells and whistles, we’ve seen a similar technique pulled off with an ATtiny85.

Building An ADS-B Receiver For Less Than You Think

November 1, 2026 by Zoe Skyforest 5 Comments

If you’ve ever wondered about the planes flying above your head, you could always listen in to ADS-B transmissions to learn more about them. [thefatmoop] has built a rig to do just that, and it comes in under $50 in parts.

The build is based around the Meshnology W12 board, which combines an ESP32-S3 microcontroller with an LR2021 LoRa Radio. The latter is able to be tuned into transmissions in the realm of 1090 MHz and it can capture ADS-B traffic that uses OOK and Manchester encoding. The data is passed to the ESP32-S3 which validates the CRCs of the captured data and serves up the aircraft tracks on a simple web interface. A GNSS receiver can also be added in so the board knows its own location as well as the location of the planes that it’s tuning in.

[thefatmoop] reports decent performance with the rig, pulling in aircraft tracks from up to 150 nautical miles away using a 915 MHz antenna. There are some mods required to achieve this performance, though—namely, you’ll want to modify the filter configuration on the board to avoid it attenuating the 1090 MHz signals of interest.

There are lots of other ways to listen to ADS-B signals, too—you can always grab yourself an SDR and get going. If you’re cooking up your own cheap radio hacks, don’t hesitate to let us know on the tipsline!

Thanks to [Moser] for the tip!

An Attempt At A Useful Desktop OS For Microcontrollers

October 29, 2026 by Jenny List 56 Comments

We’re living at an interesting time here in 2026, when microcontrollers are becoming powerful enough to surpass the capabilities of “real” computers from a time when those real computers were starting to become useful. We’ve seen plenty of microcontrollers emulating machines from the 1990s, but what if instead they were giving all their power to the OS? It’s a question [Thomas] is trying to answer with SylphideOS, a general purpose GUI operating system aimed at multiple microcontroller platforms.

On the surface it has a GUI that appears to owe a lot to the early Macintosh machines, but underneath it has the FreeRTOS kernel, something that has been around for quite a while. You can argue among yourselves as to whether this make it an OS in its own right or a FreeRTOS distro. Aside from driving a screen through a framebuffer it also has the hardware interfaces you’d expect, for keyboard and storage. There’s support for RP2350 and selected ESP32 platforms so far, as well as an emulator.

We have already seen a few operating systems for microcontrollers that provide a user interface for a binary bootloader rather than persisting under whatever programs are running, so this marks an interesting departure. Only time will tell if it becomes a success, but perhaps it’s one to watch.

SIMD-accelerated Machine Vision On An ESP32-S3

October 27, 2026 by Maya Posch 8 Comments

Recently [shraiwi] decided to have a bit of good nerdy fun and implement the FAST machine vision algorithm on an ESP32-S3 using its SIMD ISA. This involves using the assembly instructions for the ISA, making for an exciting opportunity to become familiar with this part of this Xtensa Lx7-based twin-core MCU.

The Features from Accelerated Segment Test (FAST) algorithm is a corner detection method that can determine with reasonable accuracy and in real-time whether a given input frame contains said corners which thus may correspond to objects and other characteristics worthy of note. This is essential for machine vision, with machine learning able to bump up its recognition accuracy even more.

Implementing this algorithm on the ESP32-S3 proved to be a bit of a challenge due to somewhat limited SIMD ISA. Missing instructions included things like comparisons between unsigned byte values, and there is no support for direct misaligned reads.

All of these required some creative coding to work around, but in the end the ESP32-S3 running at 240 MHz was able to process a VGA stream in real-time at 30 FPS. This means about a 2x speed-up over a naive implementation using only non-SIMD instructions.

If you want to play along at home, the Platform IO project is made available on GitHub.