Hacking A Video Walkie Talkie’s TXW818 MCU And Running DOOM

May 24, 2026 by Maya Posch 10 Comments

Recently cheapo video walkie-talkies popped up on everyone’s favorite online retailers, which naturally lured in the usual gaggle of reverse-engineering enthusiasts of cheap tat to see what’s inside these devices, as well as what more they can be made to do. Cue [Aaron Christophel] doing just that, with the typical DOOM demo as proof of concept.

Inside these cheerful little devices is a TXW818 MCU, made by TaiXin Semiconductor. It provides its own CK803 CPU core at 240 MHz with 272 kB of SRAM, as well as BLE and 2.4 GHz Wi-Fi support. For these walkie-talkies an additional 4 MB of PSRAM is provided as well as 2-4 MB of SPI Flash.

The display is a glorious 240×320 LCD, which actually fits rather well with a game like DOOM. As also explained on the GitHub project page, to build the project you simply have to fetch the CDK IDE and build the binary. After that it can be flashed with an STM32F103 ‘Blue Pill’ based board.

According to [Aaron] the SDK is rather convoluted and not that nice to work with, so it’s not a sleeper ESP32 alternative, but these cheap walkie-talkies could be nice to tinker with anyway. Other than playing games, of course, as the side buttons aren’t very conducive to gaming, and the limited Flash space required compressing the WAD game file.

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Adorable ASCII Aquarium Lives On Your Desk

May 24, 2026 by Donald Papp 23 Comments

[Kert Gartner]’s ASCII Aquarium turns a cheap yellow display (CYD) into a tiny simulated aquarium, complete with ASCII sea creatures each with their own behaviors. There’s all kinds of options and even timekeeping functionality, so the miniature water world can also pull its weight as a desk clock.

The fish and other animal movements are not a series of canned animations; each creature has its own behaviors and responses to things like feeding, which is accomplished by tapping on the screen. A hidden menu offers a wide range of configuration and display options, and there’s even an option to export screen contents as bitmaps.

Add a 3D-printed enclosure and the whole thing looks like a pretty nice weekend project. There’s even a display flip mode, just in case you have a spare 50 mm beamsplitter kicking around.

It’s a very clever use of a CYD that shows how good color and graphics can look when one designs with the hardware’s capabilities (and limitations) in mind.

The CYD is an ESP32-based development board with integrated touchscreen display, and is known for its affordable price and wide availability. This one would look great next to a CYD electric jellyfish.

A tiny, rectangular, 3D-printed box with an e-paper display and a fortune cookie design beneath it. The fortune reads: "Your next firmware update will both solve and create problems."

E-Fortune Cookie Will Humble, But Never Crumble

May 21, 2026 by Kristina Panos 5 Comments

Will your next project be a success? Only time will tell, but if you build [gokux]’s tiny ESP32 fortune cookie, we predict that, at the very least, there won’t be any crumbs involved.

After briefly entertaining the idea of shoving an ESP32 in a standard fortune cookie, [gokux] thought better of it and came up with this instead. Once shaken, this small gadget displays a fortune on its e-paper screen. It can store over 3,000 fortunes and works entirely offline, so you’re never without an oracle.

Inside you’ll find a Seeed Xiao ESP32-S3 Plus and a matching e-paper display board. [gokux] is detecting the shakes with an MPU-6050 accelerometer, and powers everything with a small Li-Po pouch.

If you tire of the fortunes that shake out, the small buttons on the left side will get you into the other modes, which are a dice roller and a coin flipper. Again, you just shake the thing until you get what you want. Be sure to check it out in the video after the break.

Want to know how an MPU-6050 works, and what it looks like under the hood? Yeah, we thought so.

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The 8-bit Web Server

May 19, 2026 by Al Williams 22 Comments

Even [maurycyz] doesn’t think it is a good idea, but it is possible to use an AVR 8-bit CPU to serve web pages. Of course, it is a vastly simplified web server, but it does serve pages — OK, technically just one page — to the public Internet.

Working backward, it is fairly easy to get the microcontroller to note an HTTP request and then simply spit out a prerecorded HTTP response to provide the page. The hard part is connecting the little processor to the network. The server is dead simple, just a CPU and a scant number of components like filter caps and LEDs. The trick is to use SLIP, an ancient protocol used to connect dial-up modem terminals to the network.

Linux supports SLIP, so the MCU connects to a Linux computer via SLIP. Then the Linux computer uses WireGuard to network with the remote web server that serves [maurycyz’s] site. The SLIP implementation assumes that IP packets aren’t fragmented, which is normally true these days. TCP was a bit more complicated since you have to track the connection state and possibly re-transmit lost packets. Still, nothing the AVR with 8 K of RAM and 64 K of flash can’t handle.

Practical? No. Cool? Sort of. Funny that a disposable vape has more CPU power. Of course, something like an ESP32 is an obvious choice.

Small Engine Gets DIY EFI Upgrade

May 18, 2026 by Zoe Skyforest 27 Comments

Small internal combustion engines usually keep things simple, relying on carburetors to handle metering the correct amount of fuel and air. Recently, [Carlos Takeshita] decided his small engine could use an upgrade in the form of electronic fuel injection (EFI).

The build began with a Predator 212, a popular gasoline engine from Harbor Freight. [Carlos] set about kitting it out with a missing tooth trigger wheel to measure the crankshaft position with a hall effect sensor. The engine also scored a custom-built aluminium fuel cell, complete with a high-pressure fuel pump and regulator suitable for driving the solitary fuel injector installed in the custom intake manifold. A Teensy 4.0 is charged with monitoring a manifold air pressure (MAP) sensor and the crank position, and choosing when and how long to fire the injector to dose the engine with the correct amount of fuel. Files are on GitHub for those eager to dive deeper.

It can be quite a job to convert an engine to run with electronic fuel injection, but you’re certain to learn a lot during the install and tuning process. We’ve featured similar builds many times over the years.

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Qualcomm’s New QCC74x Appears To Target The ESP32 MCUs

May 17, 2026 by Maya Posch 38 Comments

These days wireless microcontrollers featuring built-in WiFi and Bluetooth are all the rage, with Espressif’s range of ESP32 MCUs being the default option for commercial and hobbyist projects alike. This makes Qualcomm’s recently released QCC74x MCU rather interesting, as specification-wise it would seem to be placed firmly in ESP32 territory.

On the radio side you get 1×1 WiFi 6, Bluetooth 5.4, and IEEE 802.15.4 (e.g. Thread and Zigbee), coupled with a single-core 352 MHz RISC-V CPU with FPU and DSP features and 484 kB of SRAM. The SDK for this MCU is hosted on Codelinaro, featuring the typical FreeRTOS-based stack, though confusingly Bluetooth and Zigbee support are currently marked as ‘not supported’. This might still be in progress.

Where the competition with Espressif feels clear is in the pricing, with the highest-performance evaluation board (QCC748M EVK, pictured above) listed for $13 (before taxes/tariffs). This gets you 8 MB of PSRAM built-in with unspecified link speed, but likely the same QSPI as used for the NOR Flash. USB support is available on this higher-end tier, while absent on the QCC743. Development documentation is also available, and looks fairly complete based on first glance.

Overall the QCC74x looks to be an upgrade to the older and significantly less powerful QCC730 MCU. Depending on software support and final pricing it could make for an interesting competitor to some of Espressif’s modules like its ESP32-C series or ESP32-S2, though the upcoming ESP32-S31 would seem to have it matched or beat on all metrics.

Win95-Tracker-CYD Is A Cheap Yellow Mod Tracker With I2S

May 8, 2026 by Tyler August 7 Comments

The Cheap Yellow Display is a great little module to start a project with, but it wouldn’t necessarily be our first choice for an audio device. That’s because the PWM on the ESP32 isn’t exactly going to put out hi-fi, and the I2C pins needed for the I2S audio protocol aren’t broken out on the CYD board. That didn’t stop [ivans805] AKA [Ill-Town-5623]– he wanted a mod tracker, he had a CYD board, and necessity is the mother of invention.

It isn’t exactly a ground-breaking hack: he’s just tossed a bodge wire to the pin he needs on the ESP32, and run it to the I2S sound module. Still, in this era of endless modules it’s nice to see someone hacking what they have rather than running to AliExpress or somewhere else for a part that has everything the project needs built in.

The bodge wire is how you know it’s a hack.

What really caught our eye when we saw this project on the ESP32 subreddit was the aesthetics. It might be called “Win95-Tracker-CYD” but that interface just screams “Amiga” to us– look at that Boing Ball! Given where MOD files come from, that’s perfect. The UI was made with Lopaka.app, which we haven’t seen before but appears to be a sort of WYSIWYG editor for embedded device interfaces.

While you don’t need an ESP32 to play mod files– the diminutive CH32 can manage the task— there’s no arguing the CYD could make a nice little player. If you actually wanted to push its limits, you might try a 3D engine instead,