Microcontrollers

2407 Articles

ToothPaste Goes Where Your Password Manager Doesn’t

November 3, 2026 by 20 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 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 55 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 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.

ESP32 Rotary Display Makes Ideal Timer

October 27, 2026 by 16 Comments

We’re big fans of pushing hardware into situations it wasn’t designed for here at Hackaday, but sometimes you’ve got to appreciate a nicely designed gadget doing more or less exactly what it was intended for — especially when it’s courtesy of code that’s freely available for you to run and hack on however you like.

That’s precisely what [mircemk] has done with their “Universal Timer” project. The 2.1 inch CrowPanel “Rotary Display” at the heart of the build combines an ESP32-S3 with a 480×480 round touch screen display and a rotary encoder.

The all-in-one device — clearly meant to be reminiscent of the Nest thermostat and similar commercial offerings — is technically all you need, but in this case it’s been joined by a PCF8574 I2C I/O expander which in turn is used to drive a buzzer that provides a bit of audio feedback at the end of the countdown.

With the code [mircemk] has provided flashed onto the board, the rotary encoder ring built into the housing makes for an exceptionally intuitive input for setting the desired time. It’s a bit like a high-tech version of the classic kitchen timer, as shown in the video below, you simply twist the ring and the graphics on the display rotate accordingly. Unlike grandma’s clockwork timer of old however, this one can change color as it nears zero, which makes it easier to estimate how much time remains from across the room.

As the popularity of smartwatches has brought the cost of these circular displays down, we’ve started to see some very slick projects utilizing them. The various efforts to turn them into desktop “radar” displays for nearby flights are a particular favorite.

Continue reading “ESP32 Rotary Display Makes Ideal Timer” →

Braino! Takes The Cheap Yellow Display To School

October 16, 2026 by 23 Comments

These days, it’s common to give even very young children a mobile device loaded up with educational software that aims to improve everything from basic motor skills to reading and arithmetic. But even the cheapest phone or tablet isn’t the kind of thing most parents would like to see get destroyed, and there’s always a concern about giving children a device that’s capable of connecting to the Internet.

Which is where Braino! from [Ankush Pandit] comes in. This suite of applications can be easily flashed to a common Cheap Yellow Display to turn it into a legitimate educational tool. Combined with a 3D printed case, the total cost of the build is low enough that you don’t have to feel bad about handing it off to even the roughest of youngsters.

[Ankush] makes it clear that this project isn’t trying to sell you anything. You’re responsible for picking up a compatible CYD and installing Braino via the web flashing application. The software is released under the GPLv3 license, and it contains no ads, user accounts, or cloud connectivity. We know not everyone is thrilled with how much time young kids spend staring at screens these days, but opinions on modern parenting aside, it’s hard to find fault with the way things have been implemented here.

When the parent sets up Braino they can pick which of the 40 games can be accessed, allowing the experience to be tailored to the individual child’s age and ability. Should you decide to enable Bluetooth, some of the games even support wireless multiplayer between devices.

The commonality of the Cheap Yellow Display is one of its best features, and Braino does an excellent job of showing why that’s so important. Trying to develop a project like this without a standardized platform of some type would be a non-starter, but when anyone can get a CYD sent to their house from Amazon and flash it right from the browser, it’s makes the whole thing far more accessible.

Continue reading “Braino! Takes The Cheap Yellow Display To School” →

Using An ESP32-C3’s RF Hardware For DVB-S2 Video Transmission

October 14, 2026 by 12 Comments

Generally the DVB-S and -S2 standards require a satellite somewhere in Earth orbit to provide a signal to receive, but you can also transmit your own DVB-S2 stream with any RF transmitter if you’re so inclined. Courtesy of recent breakthroughs in using the RF hardware of the ESP32 on a raw level, [SP8ESA] has created the ESP32-DATV project using which you can broadcast a DVB-S2 signal using an ESP32-C3.

While a host PC side application handles the heavy lifting of turning the input video signal into a DVB-S(2) compliant signal, it is the ESP32-C3 that prepares the samples for transmission before sending them off to its RF block, with no external hardware needed.

If this brings to mind the idea of using an off-the-shelf DVB-S2 receiver to play back the signal, the frequency range for DVB-S2 is 10.7 – 12.7 GHz, while the ESP32-C3 is limited to roughly 2.4 GHz courtesy of it targeting only 2.4 GHz Wi-Fi and Bluetooth signals.

Using the ESP32 to transmit is already heating up.

Thanks to [ftg] for the tip.