A light-up clock displays the day of the week.

What Day Is It Again? Check The Clock

January 22, 2025 by Kristina Panos 7 Comments

If you’re lucky enough to work from home, you’ll soon find that it presents its own set of challenges, mostly related to work/life balance. It can get so bad that you don’t know what day of the week it is. Really. Ask us how we know.

Rather than miss a meeting (or a day off), prolific hacker [Arnov Sharma] created this day of the week clock. It uses a customized LED driver board with seven sets of three LEDs, each driven by a MOSFET. Each MOSFET is controlled by a DFRobot Mini Beetle ESP32-C3. It runs on a 2200 mAh, 3.7 V lithium-ion battery.

While this is mostly PCBs, there are three printed parts that turn it into a displayable object. We really like the look of this clock — it has just the right amount of pizazz to it and reminds us of a and old movie marquee. Be sure to check out the great build instructions.

We love a good clock around here. In case you missed it, here is the latest from [Moritz v. Sivers] that uses a caustic lens to display the time.

Cyber Walkman Does It In Style

January 21, 2025 by Kristina Panos 20 Comments

One of the best things about adulthood is that finally we get to, in most cases, afford ourselves the things that our parents couldn’t (or just didn’t for whatever reason). When [Yakroo108] was a child, Walkmans were expensive gadgets that were out of reach of the family purse. But today, we can approximate these magical music machines ourselves with off-the-shelf hardware.

Besides the cyberpunk aesthetic, the main attraction here is the UNIHIKER Linux board running the show. After that, it’s probably a tie between that giant mystery knob and the super-cool GUI made with Tkinter.

We also like the fact that there are two displays: the smaller one on the SSD1306 OLED handles the less exciting stuff like the volume level and the current time, so that the main UNIHIKER screen can have all the equalizer/cyberpunk fun.

Speaking of, this user-friendly GUI shows play/stop buttons and next buttons, but it looks like there’s no easy way to get to the previous track. To each their own, we suppose. Everything is enclosed in a brick-like 3D-printed enclosure that mimics early Walkmans with orange foam headphones.

If you want an updated Walkman with keyboard switches (who wouldn’t?), check this out.

Time-of-Flight Sensors: How Do They Work?

January 20, 2025 by Al Williams 14 Comments

With the right conditions, this tiny sensor can measure 12 meters

If you need to measure a distance, it is tempting to reach for the ubiquitous ultrasonic module like an HC-SR04. These work well, and they are reasonably easy to use. However, they aren’t without their problems. So maybe try an IR time of flight sensor. These also work well, are reasonably easy to use, and have a different set of problems. I recently had a project where I needed such a sensor, and I picked up a TF-MiniS, which is a popular IR distance sensor. They aren’t very expensive, and they work serial or I2C. So how did it do?

The unit itself is tiny and has good specifications. You can fit the 42 x 15 x 16 mm module anywhere. It only weighs about five grams — as the manufacturer points out, less than two ping-pong balls. It needs 5 V but communicates using 3.3 V, so integration isn’t much of a problem.

At first glance, the range is impressive. You can read things as close as 10 cm and as far away as 12 m. I found this was a bit optimistic, though. Although the product sometimes gets the name of LiDAR, it doesn’t use a laser. It just uses an IR LED and some fancy optics.

Continue reading “Time-of-Flight Sensors: How Do They Work?” →

Stealth AirTag Broadcasts When Moved: An Experiment

January 18, 2025 by Heidi Ulrich 43 Comments

A simple yet intriguing idea is worth sharing, even if it wasn’t a flawless success: it can inspire others. [Richard]’s experiment with a motion-powered AirTag fits this bill. Starting with our call for simple projects, [Richard] came up with a circuit that selectively powers an AirTag based on movement. His concept was to use an inertial measurement unit (IMU) and a microcontroller to switch the AirTag on only when it’s on the move, creating a stealthy and battery-efficient tracker.

The setup is minimal: an ESP32 microcontroller, an MPU-6050 IMU, a transistor, and some breadboard magic. [Richard] demonstrates the concept using a clone AirTag due to concerns about soldering leads onto a genuine one. The breadboard-powered clone chirps to life when movement is detected, but that’s where challenges arise. For one, Apple AirTags are notoriously picky about batteries—a lesson learned when Duracell’s bitter coating blocks functionality. And while the prototype works initially, an unfortunate soldering mishap sadly sends the experiment off the rails.

Despite the setbacks, this project may spark a discussion on the possibilities of DIY digital camouflage for Bluetooth trackers. By powering up only when needed, such a device avoids constant broadcasting, making it harder to detect or block. Whether for tracking stolen vehicles or low-profile uses, it’s a concept rich with potential. We talked about this back in 2022, and there’s an interesting 38C3 talk that sheds quite some light on the broadcasting protocols and standards. Continue reading “Stealth AirTag Broadcasts When Moved: An Experiment” →

A PDA From An ESP32

January 18, 2025 by Jenny List 13 Comments

The ESP32 series of microcontrollers have been with us for quite a few years now and appeared in both Tensilica and RISC-V variants, both of which deliver an inexpensive and powerful device. It’s thus shown up in quite a few handheld computers, whether they be conference badges or standalone devices, and this is definitely a field in which these chips have more to give. We’re pleased then to see this e-ink PDA from [ashtf8], which we think raises the bar on this type of device.

At its heart is an ESP32-S3, on the back side of a QWERTY keyboard PCB, and for a display it has an e-ink screen. To get over the annoying e-ink refresh when typing text it uses a hybrid of e-ink and OLED, with a small OLED holding the current line which can be periodically sent to the e-ink. Perhaps the nicest thing about the hardware though is the clear resin printed clamshell case, and a hand-cast silicone membrane for the keyboard. That has always been a part considered difficult to produce, and here he is making one from scratch. Take a look at the video below the break.

Software-wise it has a range of apps with more promised, but even as it stands it looks useful enough to work with. If that’s not enough, then perhaps an ESP32 operating system would help.

Continue reading “A PDA From An ESP32” →

All The Attacks On The RP2350

January 15, 2025 by Elliot Williams 29 Comments

Raspberry Pi’s new microcontroller, the RP2350, has a small section of memory that is meant for storing secrets. It’s protected by anti-glitching and other countermeasures, and the Raspberries wanted to test it. So this summer, they gave them out, pre-programmed with a secret string, as part of the badge for DEFCON attendees. The results of the cracking efforts are in, and it’s fair to say that the hackers have won.

First place went to [Aedan Cullen], who also gave a great talk about how he did it at 38C3. One of the coolest features of the RP2350, from a hacker perspective, is that it has dual ARM and dual RISC-V cores onboard, and they can be swapped out by multiplexers. The security module has a critical register that has disable bits for both of these processors, but it turns out that the ARM disable bits have priority. When [Aedan] glitched the security module just right, it disabled the ARM cores but left the RISC-V cores running in the secure context, with full debug(!), and the game was over. As of yet, there is no mitigation for this one, because it’s baked into the secure boot module’s silicon.

[Marius Muench] managed to pre-load malicious code into RAM and glitch a reboot-out-of-secure-mode on the USB module. This one is possibly fixable by checking other reboot flags. [Kévin Courdesses] has a sweet laser fault-injection rig that’s based on the 3D-printable OpenFlexure Delta Stage, which we’ve seen used for microscopy purposes, but here he’s bypassing the anti-glitching circuitry by exposing the die and hitting it hard with photons.

Finally, [Andrew Zonenberg] and a team from IOActive went at the RP2350 with a focused ion beam and just read the memory, or at least the pairwise-OR of neighboring bits. Pulling this attack off isn’t cheap, and it’s a more general property of all anti-fuse memory cells that they can be read out this way. Chalk this up as a mostly-win for the offense in this case.

If you want to read up on voltage glitching attacks yourself, and we promise we won’t judge, [Matthew Alt] has a great writeup on the topic. And ironically enough, one of his tools of choice is [Colin O’Flynn]’s RP2040-based Chip Shouter EMP glitcher, which he showed us how to make and use in this 2021 Remoticon talk.

Homebrew Retro Console Runs On PIC32

January 13, 2025 by Lewin Day 9 Comments

[Chad Burrow] decided to take on a noble task—building a “retro” style computer and video game console. Only, this one is built using somewhat modern hardware—relying on the grunt of the PIC32MZ2048EFH144 to get the job done. Meet the Acolyte Hand PIC’d 32.

It’s name might be a mouthful, but that chip can pull off some great feats! With a clock speed of 200 MHz, it’s not short on processing power, though RAM and flash storage are somewhat limited at just 512 KB and 2MB respectively. [Chad] was able to leverage those constraints to get a VGA output working at a resolutions up to 800 x 600, with up to 65,000 colors—though 256 colors is more practical due to memory concerns. The Acolyte Hand also rocks two 8-bit audio channels. It has a pair of Genesis-compatible controller ports as well as PS/2 and USB for keyboards and mice, along with more modern Xbox 360 controllers.

[Chad] cooked up some software to put it through its paces, too. It’s got a Tetris clone on board, and can also run Game Boy games at full speed via the Peanut-GB emulator. That provides for a pretty rich game library, though [Chad] notes he plans to develop more native video games for his system to demo at his local college. Design files are on Github for the curious.

This project is a great example of just how powerful modern microcontrollers have become. Once upon a time, just driving a simple black-and-white graphical LCD might have taken some real effort, but today, there are pixels and clock cycles to spare in projects like these. Truly a wonderous world we live in!