The Screamer Is Just Like The Clapper But Even More Annoying

May 16, 2025 by Lewin Day 11 Comments

Remember The Clapper? It was a home automation tool (of sorts) that let you turn appliances on and off by clapping. [Kevin O’Connor] has built something rather similar, if more terrifying. It’s called The Screamer.

The build is based around a Sonoff S31 smart switch. [Kevin] selected an off-the-shelf device because he wanted something that was safe to use with mains power out of the box. But specifically, he selected the S31 because it has an ESP8266 inside that’s easy to reprogram with the aid of ESPHome. He ended up hooking up a whole extra ESP32 with an INMP441 microphone over I2S to do the scream detection. This was achieved with a simple algorithm that looked for high amplitude noises with lots of energy in the 1000 – 4000 Hz frequency range. When a scream is detected, it flips a GPIO pin which is detected by the S31, which then toggles the state of the smart switch in turn. Job done.

It’s a simple project that does exactly what it says on the tin. It’s The Screamer! If you’d like to learn more about the original Clapper that inspired this build, we’ve looked at that before, too. Meanwhile, if you’re cooking up your own excuses to scream at the lights and walls in your home, please only notify the tipsline if it has something vaguely to do with electronics or hackery.

Atomic Clock Trades Receiver For An ESP8266

April 7, 2025 by Tom Nardi 20 Comments

The advantage of a radio-controlled clock that receives the time signal from WWVB is that you never have to set it again. Whether it’s a little digital job on your desk, or some big analog wall clock that’s hard to access, they’ll all adjust themselves as necessary to keep perfect time. But what if the receiver conks out on you?

Well, you’d still have a clock. But you’d have to set it manually like some kind of Neanderthal. That wasn’t acceptable to [jim11662418], so after he yanked the misbehaving WWVB receiver from his clock, he decided to replace it with an ESP8266 that could connect to the Internet and get the current time via Network Time Protocol (NTP).

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Wake, Boot, Repeat: Remote OS Selection With GRUB And ESP

March 3, 2025 by Heidi Ulrich 14 Comments

What do you do when you need to choose an OS at boot but aren’t physically near your machine? [Dakhnod]’s inventive solution is a mix of GRUB, Wake-on-LAN (WOL), and a lightweight ESP8266 running a simple HTTP server. In the past, [dakhnod] already enlightened us with another smart ESP hack. This one’s a clever combination of network booting and remote control that opens up possibilities beyond the usual dual-boot selector.

At its core, the hack modifies GRUB to fetch its boot configuration over HTTP. The ESP8266 (or any low-power device) serves up a config file defining which OS should launch. The trick lies in adding a custom script that tells GRUB to source an external config:

#!/usr/bin/env cat 
net_dhcp 
source (http,destination_ip_or_host:destination_port)/grub/config

Since GRUB itself makes the HTTP request, the system needs a running web server. That could be a Raspberry Pi, another machine, or the ESP itself. From there, a WOL-enabled ESP button can wake the PC and set the boot parameters remotely.

Is it secure? Well, that depends on your network. An open, unauthenticated web server dishing out GRUB configs is risky, but within a controlled LAN or a VLAN-segmented environment, it’s an intriguing option. Automation possibilities are everywhere — imagine remotely booting test rigs, toggling between OS environments for debugging, or even setting up kiosk machines that reconfigure themselves based on external triggers.

For those looking to take it further, using configfile instead of source allows for more dynamic menu entries, although it won’t persist environment variables. You could even combine it with this RasPi hack to control the uptime of the HTTP server. The balance between convenience and security is yours to strike.

If you’ve got your own wild GRUB customisation, let’s hear it!

Microwave Motion Detector Notifies Your Smart Phone

February 20, 2025 by Lewin Day 16 Comments

Your garden variety motion detector uses IR, but these days, there are fancier technologies for achieving similar goals. If so desired, you can source yourself a microwave-based presence sensor instead. Indeed, like [N-08 Labs], you might like to whip one up into a basic intrusion detection system.

The idea is simple enough—take a RCWL-0516 microwave presence sensor, and set it up to detect motion and warn you when it happens. It’s a simple part to use—it simply drives a 3.3 volt logic output high if it detects someone or something. It basically just emits a microwave signal and detects a change in phase when someone or something—usually something fleshy—is in front of it. [N-08 Labs] simply hooked one up to an IO pin on an ESP8266, with the microcontroller board set up to communicate wirelessly with a Blynk IoT app, which then in turn fires off a smartphone notification that the sensor picked something up. The whole thing is built inside the shell of an AC adapter that provides power and let it easily hide in plain sight.

A project like this doesn’t just have to be for security purposes. You might even just use it to determine when your pet (or a racoon) is using the cat door, or similar. Indeed, we’ve seen great solutions to that particular problem, too. Video after the break.

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Gimbal Clock Relies On Servos For Its Cool Movements

January 16, 2025 by Lewin Day 1 Comment

In the annals of human history, clocks got boring there for a while. Most were just variations on hands spinning in a circle, with the occasional tweeting bird mechanism to liven things up. These days, we’re treated to all kinds of original and oddball designs, like this neat gimbal clock from [Twisted&Tinned].

The concept of the build is straightforward enough. It has four main vertical arms, each with a servo at the base that rotates about a vertical axis. Upon each arm are between one and three servos which rotate 3D printed structures in the shape of numbers. A Wemos D1 Mini microcontroller commands the servos to the correct positions to display the current time. It also uses its WiFi connection to get accurate time updates directly from a network time server.

It’s quite an artistic build—and it’s rather enjoyable to watch this one flex and twist its way into displaying the right time. It’s also easier to read at a glance than some of the more unintelligible designs out there. Indeed, we see all kinds of neat and innovative clocks around these parts.

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Using The ESP8266 For Low-Cost Fault Injection

January 15, 2025 by Tom Nardi 10 Comments

As a general concept, fault injection is a technique that studies how a system reacts to unusual or unexpected external forces. The idea is that, if you can trigger a glitch at the precise moment, you might be able to use that to your advantage in disabling security features or otherwise gaining further access to the device in question. In the hardware world, this could be achieved by fiddling with the power going into the device, or subjecting it to extreme temperatures.

We’ve covered voltage glitching attacks on these pages in the past, but most of the tools used are fairly expensive if you’re not doing this kind of thing professionally. Luckily for us, [Aditya Patil] has developed a fault injection tool that can run on a standard ESP8266 development board. Obviously it’s not as capable as a bespoke device costing hundreds of dollars, but if you just want to experiment with the concept, it’s a fantastic way to wrap your head around it all.

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A chicken's egg with many holes glows beneath a glass globe set atop an inverted wooden bowl.

Glowing Egg Is A One-Oeuf Solution For Tracking Cycles

September 7, 2024 by Kristina Panos 28 Comments

Look, if something happened to you every three weeks or so to basically turn you into a different person and factored heavily into whether any new humans were created, you’d probably want to keep abreast of the schedule, yeah? Yeah. So, while there are, of course, a ton of ways to do this with your phone, most of those apps do gross things with your data. Are you angry yet?

[Jakoba the Online Witch] certainly was, or if not angry, at least annoyed. So she built a glowing egg timer, which shines a different color based on current point in her cycle, to let her know when she is fertile and expecting Aunt Flo.

The coolest part is that this is an actual egg from one of [Jakoba]’s backyard chickens. No. The coolest part is how she was able to make so many holes without breaking it. (It took four tries.)

After bleaching the insides, the egg was ready to glow. As [Jakoba] says, the guts are simple — just a Wemos D1 Mini ESP8266, a WS2812 LED, and a heatsink. The enclosure consists of an inverted peanut bowl with a glass ornament hot-glued in place.

Once it was put together, all she had to do was add it in Home Assistant and use the current calendar state to trigger services from the YAML configuration.

Would you prefer an on-body solution? Here’s an earring that tracks temperature.