Author: Jenny List

3525 Articles

Surveillance Camera Security? It’s Completely Flocked!

September 17, 2026 by 61 Comments

Surveillance cameras from Flock Safety have become a controversial privacy battleground, as the communities in which they are installed wake up to their sinister potential, and stories roll in of law enforcement professionals abusing their access. One has had its disk contents dumped, and we’ve been treated to some insights courtesy of [Micah Lee]. In short: their approach to security is deeply flawed.

It’s interesting to find that instead of a custom hardened OS, these devices run Android. Not just Android, but Android 8.1, a long out of support version originally released in 2017. This is is the year Flock Safety was founded, which may or may not be coincidental. Like any old version of a widely used operating system it has a host of known vulnerabilities, none of which are patched on this version.

The Android version is small beer compared to the revelation that they contain a hard-coded and very open-access API key that can be used by any mildly curious miscreant to reveal information from any Flock camera using its MAC address. One would hope that a product marketed for use by law enforcement might have paid attention to such a basic lapse, but it seems not. Whether or not this can be corrected by a software upgrade and the leaked key deactivated without turning off the network depends on whether thy can do upgrades tailored to specific devices, but either way we wouldn’t like to be the team tasked with fixing that one.

In a way it’s reassuring that the surveillance apparatus when it came was so incompetently managed, and we hope that these vulnerabilities will have moderated its effect. We’re sure more tasty discoveries will emerge as investigations proceed, and we’ve got the popcorn ready.

Image: Tony Webster, CC BY 2.0.

Your CYD Is Now A Telly

September 17, 2026 by 7 Comments

The Cheap Yellow Display is an all-in-one ESP32 board with a touchscreen, that’s as the name suggests, cheap. It’s appeared in a great many projects since it emerged from the depths of AliExpress, and today thanks to [Nickm324] it takes the turn of becoming a mini TV.

The tiny TV project world is one of successive developers building on previous works to deliver their own refinements on the idea, so this one borrows heavily from an earlier ESP32 project. Its twist on the idea is a single button interface using the CYD’s BOOT button. It supports a range of “channels” of which each one is a different piece of media played from the SD card. As far as we can see it’s only able to play synchronised .mjpeg and audio files, probably a shortcoming of the older ESP32 found on the CYD. The photo features a rather cutesy retro 3D printed TV case which annoyingly isn’t linked from the repository at the time of writing.

It’s a nice idea, and the CYD makes it as easy as possible with minimal wiring. Yes it’s a novelty, but we’re guessing there could be many non-novelty applications for it too. It’s certainly not the first such project we’ve seen, here’s an earlier one.

Keep Your Back Cool While Others Melt

September 17, 2026 by 17 Comments

With an El Niño event in full swing those of us in the northern hemisphere have just had a roasting hot summer, and those in the southern are about to have one. We know what that means, even with the best laid plans the slightest bit of exercise is going to raise a lot of sweat. And if you’re carrying a backpack that means a soaking down your back. Never fear though, because for that one, [Crafterboi] is here with a fan-assisted back protector.

The idea is simple enough, an open framework that sits between you and the backpack, allowing air to flow. If that weren’t enough, there are a couple of 5 volt fans at the top to blow air through the space. It’s printed using PETG, because as he explains, on a really hot day some surfaces can exceed the temperature at which PLA starts to soften.

We like the idea of this project, but what we especially like is that his prototype was made of a pizza box. ten out of ten for resourcefulness! Meanwhile this isn’t the first time we’ve seen a cooling backpack as others have had Peltier systems and evaporative coolers. We would link you to them, but sadly those are both from Hackaday’s early years and link rot has taken their websites.

A Super-Accurate Clock Using A Tiny Microcontroller

September 15, 2026 by 27 Comments

DCF77 is a German VLF transmitting station that broadcasts a time signal across Europe on 77.5 kHz. Thus a common sight in a European home is a clock emblazoned with the words “Radio controlled”. With the timing broadcast in a simple and low speed digital format it doesn’t require the greatest of hardware to decode, and a small microcontroller can handle the task with ease. And there are few smaller than an ATtiny as used in [kwolf1909]’s decoder. It takes a DCF77 bitstream from a receiver, and shows the time on an I2C display.

The receiver isn’t part of this project, however a single-frequency longwave receiver is not a difficult thing to build. The interface is a push-button, for which a short press cycles between display modes and a long press triggers a DCF77 reset. It also supports an external temperature sensor and real time clock module, if you’re using an ATtiny with enough pins.

We like this project; it’s simple and does one thing well, and it’s a welcome reminder that not every device needs a powerhouse of a processor. If you’re interested enough to build your own, we’ve featured someone doing a deep dive into the signal before.

Every ZX81 Expansion Card You Ever Wanted, All At Once

September 15, 2026 by 25 Comments

The Sinclair ZX81 was a masterpiece of Sir Clive’s desire to get the most out of the least hardware, being about as minimalist as it was possible to get and still be a home computer in 1981. As such it has a keyboard, a Z80, TC and cassette interfaces, 1K of memory, and that was it. There were any number of add-ons for it, but if you were a 1980s kid the chances are you couldn’t afford them. So 45 years later here’s [adam.klotblixt] with OpenSpand — every ZX81 expansion you could think of, all in one!

For a start there’s a RAM expansion. Not the paltry 16K of old, this is user-configurable and has the whole 64K address space minus the ROM to play with. Then there’s SD card storage, hijacking Sinclair BASIC’s LOAD and SAVE commands. It’s got high-res graphics, emulated sound chips, a joystick port, serial ports, a choice of ROMs, and a composite video output. Perhaps the only thing it doesn’t have from back in the day is a printer interface, but we’re sure the serial port could be pressed into service somehow.

It does this all as you might expect these days, with an RP2350 emulating the real parts. The microcontroller disables the onboard RAM and ROM and emulates those too, such is the disparity in power between it and a Z80. We would have done anything for this expansion, back in the day.

The ’81 features here quite often, most recently in a look at Sinclair’s own RAM expansion.

An Open Heart Rate Monitor

September 14, 2026 by 10 Comments

If you spend any time near a gym, you may be familiar with Bluetooth heart rate monitors — a small pack of electronics mounted on a strap round the chest which can relay heart rate data to an external logger or display. We’re pleased to see [Milos Rasic]’s project then, an open-source version of one of those monitors.

The heart rate capture is done by an AD8232, while the Bluetooth part is handled by a Seeed Studio XAIO ESP32 board. Power is provided by a single 3.7 V cell, with a boost converter to push that up to 5 V. The design omits a charge controller to keep things simple, so figuring out how to top off the cell is left as an exercise — no pun intended — for the user. Software is loaded through the Arduino IDE, which raises the possibility that other ESP32 CPUs could be supported with a bit of modification. All in all it’s a surprisingly simple project, and while the manufactured version is cheap enough it’s still very much worth having one that’s open source.

If you’d like to know more about his quest to develop open medical devices, check out the talk [Milos] gave on the intricacies of blood pressure monitoring earlier this year at Hackaday Europe.

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A UPS For Your Pi That’s A Little Different

September 14, 2026 by 23 Comments

There are many uninterruptible power supply (UPS) solutions for the Raspberry Pi that take the form of HATs with a battery on board, but they’re not suitable for every situation. Web3-Pi are using the Pi 5 as an Ethereum node, and found the need for a UPS that didn’t sit on top of the Pi. Their solution is the Web3 Pi UPS, a device that sits in the USB power chain.

It’s a box that takes three power inputs, USB-C PD, a barrel jack, or a hot-swappable Sony camera battery, and puts out the constant 5 V at 5 A the Pi requires. The USB output isn’t just for power, it can communicate with the Pi to deliver telemetry and ask the OS to shut itself down if power reserves are failing. Inside are a CH32 RISC-V microcontroller that handles the power circuitry, and an RP2040 that handles control and an OLED screen for a UI. The project’s web site also mentions provision for an LTE add-on for remote monitoring, however this doesn’t at the time of writing appear to be fully implemented in the GitHub repository.

While it’s probable that few of you are mining Ethereum on your PI, we can see that there are plenty of other situations that this project could find a home in. It’s not the first Pi UPS we’ve seen, though some of them are considerably less complex or capable.

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