A high level pictorial schematic of the basement monitor.

Making Sure The Basement Stays Dry With An ESP8266

May 17, 2025 by John Elliot V 38 Comments

The hack we have for you today is among our most favorite types of hack: a good, honest, simple, and well documented implementation that meets a real need. Our hacker [Solo Pilot] has sent in a link to their basement monitor.

The documentation is quite good. It’s terse but comprehensive with links to related information. It covers the background, requirements, hardware design, sensors, email and SMS alerts, software details, and even has some credits at the end.

Implementing this project would be a good activity for someone who has already made an LED flash and wants to take their skills to the next level by sourcing and assembling the hardware and then configuring, compiling, deploying, and testing the software for this real-world project.

To make this project work you will need to know your way around the Arduino IDE in order to build the software from the src.zip file included with the documentation (hint: extract the files from src.zip into a directory called AHT20_BMP280 before opening AHT20_BMP280.ino and make sure you add necessary boards and libraries).

One feature of the basement monitor that we would like to see is a periodic “everything’s okay” signal from the device, just so we can confirm that the reason we’re not getting an alarm about flooding in the basement is because there is no flood, and not because the battery ran dead or the WiFi went offline.

If you’ve recently started on your journey into where electronics meets software a project such as this one is a really great place to go next. And of course once you are proficient with the ESP8266 there are a thousand such projects here at Hackaday that you can cut your teeth on. Such as this clock and this fault injection device.

New Bismuth Transistor Runs 40% Faster And Uses 10% Less Power

May 16, 2025 by John Elliot V 39 Comments

Recently in material science news from China we hear that [Hailin Peng] and his team at Peking University just made the world’s fastest transistor and it’s not made of silicon. Before we tell you about this transistor made from bismuth here’s a whirlwind tour of the history of the transistor.

The Bipolar Junction Transistor (BJT, such as NPN and PNP) was developed soon after the point-contact transistor which was developed at Bell Labs in 1947. Then after Resistor-Transistor Logic (RTL) came Transistor-Transistor Logic (TTL) made with BJTs. The problem with TTL was too much power consumption.

Continue reading “New Bismuth Transistor Runs 40% Faster And Uses 10% Less Power” →

Wireless Doorbell Extension Features Home-Wound Coil

May 16, 2025 by John Elliot V 12 Comments

Today in the it’s-surprising-that-it-works department we have a ding dong doorbell extension from [Ajoy Raman].

What [Ajoy] wanted to do was to extend the range of his existing doorbell so that he could hear it in his workshop. His plan of attack was to buy a new wireless doorbell and then interface its transmitter with his existing doorbell. But his approach is something others might not have considered if they had have been tasked with this job, and it’s surprising to learn that it works!

What he’s done is wrap a new coil around the ding dong doorbell’s solenoid. When the solenoid activates, a small voltage is induced into the coil. This then gets run into the wireless doorbell transmitter power supply (instead of its battery) via a rectifier diode and a filter capacitor. The wireless doorbell transmitter — having also had its push-button shorted out — operates for long enough from this induced electrical pulse to transmit the signal to the receiver. To be clear: the wireless transmitter is fully powered by the pulse from the coil around the solenoid. Brilliant! Nice hack!

We weren’t sure how reliable the transmitter would be when taken out of the lab and installed in the house so we checked in with [Ajoy] to find out. It’s in production now and operating well at a distance of around 50 feet!

Of course we’ve published heaps of doorbell hacks here on Hackaday before, such as this Bluetooth Low Energy (BLE) doorbell and this light-flashing doorbell. Have you hacked your own doorbell? Let us know on the tips line!

Continue reading “Wireless Doorbell Extension Features Home-Wound Coil” →

A man aims the LED flashlight into the night sky.

The World’s Longest Range LED Flashlight

May 13, 2025 by John Elliot V 39 Comments

[ApprehensiveHawk6178] reports that they have made the world’s longest range LED flashlight! While technically “handheld”, you’re gonna need both hands for this monster. According to the creator, it draws 1.2 kW (20 A @ 60 V) to deliver 100,000 lumens and approximately 20,000,000 candelas.

This spotlight is made from 48 white LEDs, wired in 16S3P configuration, and is powered by a similarly beefy 20S2P battery pack. That 1.2 kW power draw generates a lot of heat which is dissipated with an array of heat sinks and five cooling fans. Total cost was in the order of $2,000 USD.

It can be controlled via Bluetooth, and can run from its batteries for 30 minutes at full power. If you’d like to geek out over the specs click-through and read the discussion, a lot of technical detail is given and there are a bunch of photos showing the internals and assembly.

We’ve seen high-output LED lights with water cooling in the past, and wonder if that might be the next step for this particular build.

Thanks to [kms] for the tip.

Web Dashboard And OTA Updates For The ESP32

May 10, 2025 by John Elliot V 10 Comments

Today we are happy to present a web-based GUI for making a web-based GUI! If you’re a programmer then web front-end development might not be your bag. But a web-based graphical user interface (GUI) for administration and reporting for your microcontroller device can look very professional and be super useful. The Mongoose Wizard can help you develop a device dashboard for your ESP32-based project.

In this article (and associated video) the Mongoose developers run you through how to get started with their technology. They help you get your development environment set up, create your dashboard layout, add a dashboard page, add a device settings page, add an over-the-air (OTA) firmware update page, build and test the firmware, and attach the user-interface controls to the hardware. The generated firmware includes an embedded web server for serving your dashboard and delivering its REST interface, pretty handy.

You will find no end of ESP32-based projects here at Hackaday which you could potentially integrate with Mongoose. We think the OTA support is an excellent feature to have, but of course there are other ways of supporting that functionality.

Continue reading “Web Dashboard And OTA Updates For The ESP32” →

Superconductivity News: What Makes Floquet Majorana Fermions Special For Quantum Computing?

May 7, 2025 by John Elliot V 13 Comments

Researchers from the USA and India have proposed that Floquet Majorana fermions may improve quantum computing by controlling superconducting currents, potentially reducing errors and increasing stability.

In a study published in Physical Review Letters that was co-authored by [Babak Seradjeh], a Professor of Physics at Indiana University Bloomington, and theoretical physicists [Rekha Kumari] and [Arijit Kundu], from the Indian Institute of Technology Kanpur, the scientists validate their theory using numerical simulations.

Continue reading “Superconductivity News: What Makes Floquet Majorana Fermions Special For Quantum Computing?” →

UK CanSat Competition, Space Ex, Lancing College, Critical Design Review

Lancing College Shares Critical Design Review For UK CanSat Entry

May 4, 2025 by John Elliot V 2 Comments

A group of students from Lancing College in the UK have sent in their Critical Design Review (CDR) for their entry in the UK CanSat project.

Per the competition guidelines the UK CanSat project challenges students aged 14 to 19 years of age to build a satellite which can relay telemetry data about atmospheric conditions such as could help with space exploration. The students’ primary mission is to collect temperature and pressure readings, and these students picked their secondary mission to be collection of GPS data, for use on planets where GPS infrastructure is available, such as on Earth. This CDR follows their Preliminary Design Review (PDR).

The six students in the group bring a range of relevant skills. Their satellite transmits six metrics every second: temperature, pressure, altitude reading 1, altitude reading 2, latitude, and longitude. The main processor is an Arduino Nano Every, a BMP388 sensor provides the first three metrics, and a BE880 GPS module provides the following three metrics. The RFM69HCW module provides radio transmission and reception using LoRa.

The students present their plan and progress in a Gantt chart, catalog their inventory of relevant skills, assess risks, prepare mechanical and electrical designs, breadboard the satellite circuitry and receiver wiring, design a PCB in KiCad, and develop flow charts for the software. The use of Blender for data visualization was a nice hack, as was using ChatGPT to generate an example data file for testing purposes. Mechanical details such as parachute design and composition are worked out along with a shiny finish for high visibility. The students conduct various tests to ensure the suitability of their design and then conduct an outreach program to advertise their achievements to their school community and the internet at large.

We here at Hackaday would like to wish these talented students every success with their submission and we hope you had good luck on launch day, March 4th!

The backbone of this project is the LoRa technology and if you’re interested in that we’ve covered that here at Hackaday many times before, such as in this rain gauge and these soil moisture sensors.