A More Convenient IButton Reader

June 24, 2026 by Zoe Skyforest 2 Comments

iButtons are microchips housed in small, round, metal containers, and are similar to coin cell batteries in appearance. Among other things, they’re used for logging data in industrial contexts, particularly where it’s desirable to track parameters like temperature over time. [Geoffrey Wells] has worked with these sensors, and decided that the aging solutions for reading these devices are too cumbersome and out-of-date. Thus, he designed ChillPoint as a more modern solution.

As you might have guessed by the name, [Geoffrey] was inspired to build a rig specifically for inspecting iButton data loggers in cold chain logistics applications. It’s built around an ESP32-C6, which has a 1-Wire probe on the front for communicating with the target device. On contact, the reader dumps all the data, storing it on its own flash storage. The data can then further be accessed by connecting to the ChillPoint handheld device over its own WiFi access point, upon which it hosts a web UI for access. The handheld can be used for scanning iButtons single-handed, while a smartphone, tablet, or laptop can be used as a screen to monitor the results live.

The project is nearing completion, and [Geoffrey] says both the hardware and software will be open source once it’s all said and done. Anyone interested in adding a ChillPoint to their toolbox should keep an eye out for its upcoming CrowdSupply campaign.

If you find yourself working with these devices on the regular, this project may be appealing to you. We’ve looked at iButtons many times over the years.

This Alarm Clock Has The Capacity To Wake You

June 15, 2026 by Jenny List 12 Comments

Every now and then a project comes into the Hackaday feed that has so many levels of wrong about it that you really shouldn’t do it at home, but is amusing enough to feature anyway with a warning. So it is with [ArcaEge]’s Capacitor Alarm Clock, which wakes up its unfortunate owner by blowing up electrolytic capacitors with reverse voltage. If you survive, you’ll certainly be awake!

It’s inspired unsurprisingly by an [ElectroBoom] video, and the premise is simple enough. An ESP32 serves as the clock, and triggers a relay for the alarm, which in turn overloads a suitably low-voltage electrolytic capacitor in a socket. The resulting explosion which appears in a video we’ve placed below the break, wakes the slumberer.

We don’t have to tell you that this is not the safest of hacks, and is presented here only for your entertainment. But it does provide a few points of interest, for example in identifying the difference between capacitors with a vent, and those without.

This isn’t the first time we’ve seen a project based around exploding capacitors, and that one maybe was a don’t-do-this-at-home too.

Continue reading “This Alarm Clock Has The Capacity To Wake You” →

Ebike Display Uses Reflective LCD

May 31, 2026 by Bryan Cockfield 19 Comments

Although LCD displays have been used in almost every type of consumer electronics display over the last two decades, many of these screens have a few downsides that limit their usefulness in certain situations. As any owner of an early digital watch, an early laptop, or an early digital camera will testify, these displays often completely fail in direct sunlight. And, a currently new technology often using inexpensive displays in full sunlight conditions is ebikes, so [Volos Projects] decided to use a unique LCD display to solve this issue.

The display is called a reflective LCD (RLCD) and is actually a fairly old but overlooked piece of technology. Displays like these have a reflective layer that bounces ambient light back to the user, increasing contrast and readability in high light, especially when compared to more common transmissive displays. This build is based on a board from Waveshare, which includes the screen and its driver components, and [Volos Projects] integrated this into a test stand that mimics an ebike’s speed sensor and other hardware like turn signals. The display shows the bike’s speed and a few other indicators, and thanks to the screen, this information can be easily seen in full sun.

Although he doesn’t have it on an actual e-bike yet, he hopes it will be useful for those who want to try out something like this with their substandard e-bike displays. The code he’s used is available on a GitHub page for anyone interested. We’d imagine that a low-cost display like this would pair well with an open-source ebike like this one.

Continue reading “Ebike Display Uses Reflective LCD” →

ESP-Osito Eschews Retrocomputing For Modern Code On Modern, Equivalent Hardware

May 29, 2026 by Tyler August 12 Comments

If you’re of a certain vintage, you have probably looked at some of the microcomputers on the market these days and thought “that would have been a decent workstation back in the day!”. We certianly have, and so did [Roberto Alsina]. Rather than allow himself to contemplate his age and threfore rapidly approaching mortailty, [Roberto] wrote a useful operating system called ESP-Osito for the Cheap Yellow Display, which he refers to as “the cheapest computer”. He’s not wrong, and it’s certainly a better use of time than an existential crisis.

He explains some of his reasoning behind the project in an accompanying blog post, but on the project page he compares it to a Palm Pilot– it’s on quick, apps load quick, and the API is simple enough for easy app creation in a few hundred lines of C, unlike certain pocket computers we won’t name. Sure, there’s no multitasking, but when apps jump from SD card to run in memory in microseconds, who cares? Saving the current state of the app back to SD means the experience is virtually identical from a user perspective anyway.

DOS knew what time it was, but how many of us wasted phone time for weather reports?

As this is a one-man show for now, the app store won’t quite rival your smart phone– but there’s everything you’d expect on the 90s-era computer this has the horsepower of: a serial terminal, a text editor, a file explorer, a calculator, a clock, but also some things that aren’t so retro. The clock app gives weather info via futuristic wireless networking, the reader app takes Markdown text, and the chat app connects to an LLM somewhere instead of your friends on IRC. The blackberry keyboard option gives it a feel of a slightly different vintage. You can also play snake, because no computer is complete without games. The OS and all its applications are released under the MIT license on GitHub, and [Roberto] is actively looking for collaborators.

If you doubt the workstation comparison at the start of this article, this CYD runs Macintosh System 3 via a 68k emulator. That’s got old-school cred, but there’s something great about having retro constraints with modern code on modern hardware. In that way, ESP-Osito is similar to the 3D graphics engine behind this Wipeout clone.

A black-and-white clock face is shown. The numerals are ranged around the right edge of the clock. One pointer extends from the center of the clock, and one is on the left side of the face.

A Clock Inspired By Failed Cognitive Tests

May 27, 2026 by Aaron Beckendorf 86 Comments

One simple screening tool for cognitive impairment is the clock-drawing test (CDT): the patient is provided with a printed circle and asked to draw a clock face with the hands pointing to a certain time. Depending on how the clock is drawn, this could indicate a variety of different disorders, particularly dementia, with a particular deformity in the drawing sometimes pointing to a specific issue. These failed tests inspired [John Silvia] to create a clock with a unique, disordered face.

The numerals in this clock face are placed exclusively along the right half of the clock (in the test, this can be a sign of damage to the right parietal lobe, or of executive dysfunction caused by dementia), and out of order. The hour hand is controlled by a servo motor, and the minute hand is mounted on a separate, commercially-purchased clock mechanism on the left-hand side of the face.

The frame for the clock and the face are 3D-printed, and the servo motor is controlled by an ESP32-C3 with an RTC module. To minimize power draw, a MOSFET disconnects the servo motor from power except for the once-per-hour position update. Once per month, the ESP32 connects to Wi-Fi to synchronize to NTP time, otherwise remaining in a low-power state – even its indicator LEDs are disconnected to save power. These efforts paid off: when the servo isn’t active, it draws only about 160 µA, and a set of three AA NiMH cells lasts about a year.

Since the servo motor draws most of the power budget, it wouldn’t make much difference, but the ESP32’s co-processor can also be used for ultra-low-power projects. For a happier take on a drawing-related clock, check out one of these projects.

Drawing Videos On An Etch-a-Sketch

May 26, 2026 by Julian Scheffers 2 Comments

We’ve covered etch-a-sketch robots before, but usually they’re not quite as fast as [Every Flavor of Robot]’s “video” etch-a-sketch, capable of drawing a full portrait in as little as a minute.

The robot, nearly finished drawing a portrait of [William Osman]

The idea comes from the motivation to make something cool for Open Sauce. Of course, most projects with a deadline come very close to missing it, and–like many an Open Sauce project–this one is no exception. Arriving in California, they realize they couldn’t access their code! Fortunately, they get a demo working where your portrait is drawn just in time.
Continue reading →