A Tiny OS For A Tiny Board

November 5, 2026 by Jenny List 14 Comments

As microntrollers have become ever more powerful, we have started to see an increasing number of operating systems written to take advantage of this extra power. Usually they’re aimed at handheld or other similar devices with support for screens and input devices, but just what can be done if a developer eschews those niceties? KoaOS is a small OS for the ESP32-S3 on the Heltec WiFi LoRa 32 V4, and it’s headless. You can only talk to it via a serial terminal on its USB port.

What it provides is a UNIX-like shell, with editor, GPS, weather and APRS apps ready to run. It’s not just limited to those, there’s an SDK of sorts to create new apps and compile them from C. These .esp files can be installed and uninstalled at will over the network.

There are a few limitations, for example it’s only for the Heltec V4 due to a large requirement for PSRAM. We are guessing that another similar spec board could probably be made to perform, however it’s clear that hasn’t yet been done. Despite that we think this OS is interesting for concentrating on the OS rather than the interface, and we hope to see it develop further.

Several takes on an ESP32 OS have appeared in recent times, including this JavaScript one.

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.

A Game Engine For Microcontrollers

November 1, 2026 by Zoe Skyforest 22 Comments

If you wanted to make a game that ran on a commodity microcontroller, you could be forgiven for not knowing where to start. Never fear, for [Fedyfausto] has just the setup to help you in your quest.

It’s called Jet Studio, and it’s an open-source game editor that looks and works like Godot. In reality, it’s a Godot app with a C++ GDExtension, and it’s for making games that run on an Arduino Nano ESP32 or an STM32F746. Specifically, it’s intended for use with the commonly-available ILI9341 SPI LCD display.

The engine can be used for both 2D and 3D games with a handy level of performance. [Fedyfausto] notes that a 2D shooter runs at 62 FPS on the Nano ESP32 and 83 FPS on the STM32. Other fun demos include a partially-3D Outrun-style game, and a 3D physics simulation. They show just what the engine can do, and from there, it’s really up to your creativity for what you choose to make with it.

We see all kinds of games ported to the microcontroller world these days; you can even run Metal Gear Solid on an ESP32 if you really feel like it. What a world we live in. Video after the break.

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Building A Simple Internet Radio

October 21, 2026 by Zoe Skyforest 35 Comments

Broadcast radio isn’t as popular as it once was, its popularity suffering in turn due to technologies like MP3 players and music streaming services. If you don’t fancy either of those, you might like to listen to some internet radio stations, using a rig like the one [CodersCafeTech] built.

It’s a simple desktop radio set, but instead of tuning in to AM or FM broadcast bands, it has an antenna for 2.4 GHz instead. That’s because inside this radio is an ESP32-S3 development board, which is equipped with onboard WiFi hardware that lets it connect to the internet. It’s hooked up to a 1.3-inch OLED display over I2C, which acts as a user interface in concert with a rotary encoder. Sound is handled with a MAX98357 I2S audio amplifier, hooked up to a small 3 W speaker. Once programmed appropriately, all the unit needs is a WiFi SSID and password, and the URL for the internet radio station you’d like to listen to.

We’ve featured a few internet radio builds over the years, as well as a rather fun build that saw a Macintosh SE/30 hooked up to Spotify. If you’re tinkering with something along those lines, don’t hesitate to let us know on the tipsline!

5 GHz Drone Video, With An ESP32

October 20, 2026 by Jenny List 39 Comments

With the ESP32 series of microcontrollers having had hidden software-defined radio (SDR) facility revealed, we’re now moving on from the announcement into projects making use of the finding. [Twotoz] has one using an ESP32-C5, to receive and demodulate analog FM video.

You might think that video is something which has largely gone away in 2026, with TV transmissions having made the switch more than a decade ago, and home entertainment appliances having used HDMI for longer. But it’s still very popular in the world of drones however, where it exists as 5 GHz FM transmission. There’s no digital cliff-edge to lose your picture if you fly into somewhere with bad propagation of radio waves, and perhaps more importantly, it has an extremely low latency. This receiver uses a Seeed Studio Xiao ESP32-C5 board with a simple resistor-ladder DAC to produce the video. It has a simple button channel interface, and a serial link for more in-depth options.

It’s good to see these projects appear, especially as this one’s 5 GHz and shows those chips work too with the hack. We’d be interested to know whether the latency of the SDR affects its usability though. You may be interested to know this isn’t the first time we’ve seen an SDR do video.

Thanks [Ink] for the tip!

2026 Retrocomputing Challenge: Dollhouse Arcade Cabinet Runs Remote DOS Games

October 17, 2026 by Donald Papp 5 Comments

Classic DOS games never ran from within stand-up arcade cabinets in dollhouses, but [Juha Lilja] imagines a world in which they did. His Micro DOS arcade cabinet is described as a device that “runs nothing” because the tiny unit is actually streaming the games over Wi-Fi from a nearby PC. That doesn’t mean it’s just a glorified movie player, though — the cabinet is playable, if a bit awkward to do so.

An economical development board and a 3D-printed enclosure is all it takes to put classic DOS games into dollhouse-sized arcade cabinet.

The core of the micro arcade cabinet is a M5Stack AtomS3R running as an embedded remote terminal. One tilts the whole cabinet as if it were a virtual joystick to send up, down, left, and right. Button presses are done by pushing on the physical screen; it supports single, double, and long-clicks. While in theory one could install a micro joystick and buttons instead, [Juha] aimed to keep everything self-contained and use only what was already built into the AtomS3R. In this case, that’s a motion sensor and the single button which is activated by pressing the screen.

The games themselves run on a PC, with screen contents being streamed wirelessly to the little display and inputs being sent back. The firmware on the AtomS3R doesn’t know or care what game is being played; all it does is display what it’s told, and send back input events. The back end does the rest. This makes it pretty flexible, and a tiny arcade cabinet is a handy way to demonstrate the whole system. It’s a pretty slick addition to his daughter’s dollhouse, too.

If streaming DOS games (or whatever else) to economical endpoints is giving you some ideas, the GitHub repository holds code and a fuller explanation of how it works. There’s a deeper discussion on some of the finer technical points, as well. Watch it in action in the video embedded just below the page break.

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So You Want To Make Your SDR Work On Other Frequencies

October 15, 2026 by Jenny List 25 Comments

Perhaps the most exciting news of the past few weeks in the world of hardware hacking has been the unlocking of hidden SDR functionality in the Wi-Fi radios found on Espressif ESP32 microcontrollers. They can be used as both transmit and receive SDRs, and given that it’s early days for this hack we expect that great things are yet to come.

There’s one snag though, despite speculation that they might be dragged down to much lower frequencies, as far as we know they’re only proven to work around the Wi-Fi frequencies. Though the reality may be wider we’ll take that for a 2.4 GHz part as a 100 MHz slice from 2.4 GHz to 2.5 GHz. Plenty of possibilities there, and they might even work down to 1.8 GHz, but there would be so much more to do if it could work elsewhere in the spectrum. So it’s time to look at the converter, a tried and tested old way to make a radio work on a different frequency.

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