A Closer Look Inside A Robot’s Typewriter-Inspired Mouth

[Ancient] has a video showing off a fascinating piece of work: a lip-syncing robot whose animated electro-mechanical mouth works like an IBM Selectric typewriter. The mouth rapidly flips between different phonetic positions, creating the appearance of moving lips and mouth. This rapid and high-precision movement is the product of a carefully-planned and executed build, showcased from start to finish in a new video.

Behind the face is a ball that, when moving quickly enough, gives the impression of animated mouth and lips. The new video gives a closer look at how it works.

[Ancient] dubs the concept Selectramatronics, because its action is reminiscent of the IBM Selectric typewriter. Instead of each key having a letter on a long arm that would swing up and stamp an ink ribbon, the Selectric used a roughly spherical unit – called a typeball – with letters sticking out of it like a spiky ball. Hitting the ‘A’ key would rapidly turn the typeball so that the ‘A’ faced forward, then satisfyingly smack it into the ink ribbon at great speed. Here’s a look at how that system worked, by way of designing DIY typeballs from scratch. In this robot, the same concept is used to rapidly flip a ball bristling with lip positions.

We first saw this unusual and fascinating design when its creator showed videos of the end result on social media, pronouncing it complete. We’re delighted to see that there’s now an in-depth look at the internals in the form of a new video (the first link in this post, also embedded below just under the page break.)

The new video is wonderfully wordless, preferring to show rather than tell. It goes all the way from introducing the basic concept to showing off the final product, lip-syncing to audio from an embedded Raspberry Pi.

Thanks to [Luis Sousa] for the tip!

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Hosting A Website On A Disposable Vape

For the past years people have been collecting disposable vapes primarily for their lithium-ion batteries, but as these disposable vapes have begun to incorporate more elaborate electronics, these too have become an interesting target for reusability. To prove the point of how capable these electronics have become, [BogdanTheGeek] decided to turn one of these vapes into a webserver, appropriately called the vapeserver.

While tearing apart some of the fancier adult pacifiers, [Bogdan] discovered that a number of them feature Puya MCUs, which is a name that some of our esteemed readers may recognize from ‘cheapest MCU’ articles. The target vape has a Puya PY32F002B MCU, which comes with a Cortex-M0+ core at 24 MHz, 3 kB SRAM and 24 kB of Flash. All of which now counts as ‘disposable’ in 2025, it would appear.

Even with a fairly perky MCU, running a webserver with these specs would seem to be a fool’s errand. Getting around the limited hardware involved using the uIP TCP/IP stack, and using SLIP (Serial Line Internet Protocol), along with semihosting to create a serial device that the OS can use like one would a modem and create a visible IP address with the webserver.

The URL to the vapeserver is contained in the article and on the GitHub project page, but out of respect for not melting it down with an unintended DDoS, it isn’t linked here. You are of course totally free to replicate the effort on a disposable adult pacifier of your choice, or other compatible MCU.

Off To The Races With ESP32 And EInk

Off to the races? Formula One races, that is. This project by [mazur8888] uses an ESP32 to keep track of the sport, and display a “live” dashboard on a 2.9″ tri-color LCD.

“Live” is in scare quotes because updates are fetched only every 30 minutes; letting the ESP32 sleep the rest of the time gives the tiny desk gadget a smaller energy footprint. Usually that’s to increase battery life, but this version of the project does not appear to be battery-powered. Here the data being fetched is about overall team rankings, upcoming races, and during a race the current occupant of the pole-position.

There’s more than just the eInk display running on the ESP32; as with many projects these days, micro-controller is being pressed into service as a web server to host a full dashboard that gives extra information as well as settings and OTA updates. The screen and dev board sit inside a conventional 3D-printed case.

Normally when talking Formula One, we’re looking into the hacks race teams make. This hack might not do anything revolutionary to track the racers, but it does show a nice use for a small e-ink module that isn’t another weather display. The project is open source under a GPL3.0 license with code and STLs available on GitHub.

Thanks to [mazur8888]. If you’ve got something on the go with an e-ink display (or anything else) send your electrophoretic hacks in to our tips line; we’d love to hear from you.

Flashlight Repair Brings Entire Workshop To Bear

The modern hacker and maker has an incredible array of tools at their disposal — even a modestly appointed workbench these days would have seemed like science-fiction a couple decades ago. Desktop 3D printers, laser cutters, CNC mills, lathes, the list goes on and on. But what good is all that fancy gear if you don’t put it to work once and awhile?

If we had to guess, we’d say dust never gets a chance to accumulate on any of the tools in [Ed Nisley]’s workshop. According to his blog, the prolific hacker is either building or repairing something on a nearly daily basis. All of his posts are worth reading, but the multifaceted rebuilding of a Anker LC-40 flashlight from a couple months back recently caught our eye.

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Going Native With Android’s Native Development Kit

Originally Android apps were only developed in Java, targeting the Dalvik Java Virtual Machine (JVM) and its associated environment. Compared to platforms like iOS with Objective-C, which is just C with Smalltalk uncomfortably crammed into it, an obvious problem here is that any JVM will significantly cripple performance, both due to a lack of direct hardware access and the garbage-collector that makes real-time applications such as games effectively impossible. There is also the issue that there is a lot more existing code written in languages like C and C++, with not a lot of enthusiasm among companies for porting existing codebases to Java, or the mostly Android-specific Kotlin.

The solution here was the Native Development Kit (NDK), which was introduced in 2009 and provides a sandboxed environment that native binaries can run in. The limitations here are mostly due to many standard APIs from a GNU/Linux or BSD environment not being present in Android/Linux, along with the use of the minimalistic Bionic C library and APIs that require a detour via the JVM rather than having it available via the NDK.

Despite these issues, using the NDK can still save a lot of time and allows for the sharing of mostly the same codebase between Android, desktop Linux, BSD and Windows.

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DIY USB-C PD Tools

USB-C PD Decoded: A DIY Meter And Logger For Power Insights

As USB-C PD becomes more and more common, it’s useful to have a tool that lets you understand exactly what it’s doing—no longer is it limited to just 5 V. This DIY USB-C PD tool, sent in by [ludwin], unlocks the ability to monitor voltage and current, either on a small screen built into the device or using Wi-Fi.

This design comes in two flavors: with and without screen. The OLED version is based on an STM32, and the small screen shows you the voltage, current, and wattage flowing through the device. The Wi-Fi PD logger version uses an ESP-01s to host a small website that shows you those same values, but with the additional feature of being able to log that data over time and export a CSV file with all the collected data, which can be useful when characterizing the power draw of your project over time.

Both versions use the classic INA219 in conjunction with a 50 mΩ shunt resistor, allowing for readings in the 1 mA range. The enclosure is 3D-printed, and the files for it, as well as all the electronics and firmware, are available over on the GitHub page. Thanks [ludwin] for sending in this awesome little tool that can help show the performance of your USB-C PD project. Be sure to check out some of the other USB-C PD projects we’ve featured.

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Neural network shown on original mac screen, handwritten 2 on left and predictions on right

Original Mac Limitations Can’t Stop You From Running AI Models

Modern retrocomputing tricks often push old hardware and systems further than any of the back-in-the-day developers could have ever dreamed. How about a neural network on an original Mac? [KenDesigns] does just this with a classic handwritten digit identification network running with an entire custom SDK!

Getting such a piece of hardware running what is effectively multiple decades of machine learning is as hard as most could imagine. (The MNIST dataset used wasn’t even put together until the 90s.) Due to floating-point limitations on the original Mac, there are a variety of issues with attempting to run machine learning models. One of the several hoops to jump through required quantization of the model. This also allows the model to be squeezed into the limited RAM of the Mac.

Impressively, one of the most important features of [KenDesigns] setup is the custom SDK, allowing for the lack of macOS. This allows for incredibly nitty-gritty adjustments, but also requires an entire custom installation. Not all for nothing, though, as after some training manipulation, the model runs with some clear proficiency.

If you want to see it go, check out the video embedded below. Or if you just want to run it on your ancient Mac, you’ll find a disk image here. Emulators have even been tested to work for those without the original hardware. Newer hardware traditionally proves to be easier and more compact to use than these older toys; however, it doesn’t make it any less impressive to run a neural network on a calculator!

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