2025 Component Abuse Challenge: Light An LED With Nothing

November 12, 2025 by Jenny List 11 Comments

Should you spend some time around the less scientifically informed parts of the internet, it’s easy to find “Free power” stories. Usually they’re some form of perpetual motion machine flying in the face of the laws of conservation of energy, but that’s not to say that there is no free power.

The power just has to come from somewhere, and if you’re not paying for it there’s the bonus. [joekutz] has just such a project, lighting up LEDs with no power source or other active electronics.

Of course, he’s not discovered perpetual motion. Rather, while an LED normally requires a bit of current to light up properly, it seems many will produce a tiny amount of light on almost nothing. Ambient electromagnetic fields are enough, and it’s this effect that’s under investigation. Using a phone camera and a magnifier as a light detector he’s able to observe the feeble glow as the device is exposed to ambient fields.

In effect this is using the LED as the very simplest form of radio receiver, a crystal set with no headphone and only the leads, some wires, and high value resistors as an antenna. The LED is after all a diode, and it can thus perform as a rectifier. We like the demonstration even if we can’t quite see an application for it.

While we’re no longer taking new entries for the 2025 Component Abuse Challenge, we’ve still got plenty of creative hacks from the competition to show off. We’re currently tabulating the votes, and will announce the winners of this particularly lively challenge soon.

2025 Component Abuse Challenge: Dawg Gone LED Tester

November 9, 2025 by Jenny List 24 Comments

The Hackaday 2025 Component Abuse Challenge is all about abusing electronic components in the service of making them do things they were never intended to. It’s not the 2025 Food Abuse Challenge, so in the case of [Ian Dunn]’s hot dog pressed into service as an LED tester, we’ll take the ‘dawg to be a component in its own right. And by any measure, it’s being abused!

Cooking hot dogs by passing an electric current through them has a long and faintly hazardous history to it — we’re sure we’ve heard of domestic hot dog cooker appliances that are little more than the mains supply on a pin at each end of a hot dog shaped receptacle. This one takes the ‘dawg in a bun with condiments, no less, and sticks an ordinary table fork wired up to the grid in each end. The LED testing is the cherry on the cake, because he simply sticks a pile of LEDs by their pins into the tasty sausage. It forms a crude potential divider, so there’s about enough volts across the gap between pins to light it up nicely.

We like this project on so many levels, though we’re not sure what heavy metals would leach out of those LED pins into the meat. If it’s inspired you to do something similar you still have a few days in which to enter the contest, so break out your convenience food and a pile of parts, and start experimenting!

A hand holding the circuit in its active state

2025 Component Abuse Challenge: A Self-Charging LED Flasher By Burkhard Kainka

October 18, 2025 by John Elliot V 8 Comments

[Tito] entered a Self-Charging LED Flasher into the Component Abuse Challenge. It’s a simple re-build of a design by the unstoppable [Burkhard Kainka], and while [Tito] doesn’t explain its workings in detail, it’s a clever experiment in minimalism, and a bit of a head-scratcher at the same time.

You press a button and an LED flashes. But there is no battery, so how does it work? Maybe the schematic to the right here will help. Or does it confound? Look at it yourself before reading on and see if you can figure out how it works.

Continue reading “2025 Component Abuse Challenge: A Self-Charging LED Flasher By Burkhard Kainka” →

2025 Component Abuse Challenge: An LED As A Light Dependent Capacitor

October 16, 2025 by Jenny List 15 Comments

The function of an LED is to emit light when the device is forward biased within its operating range, and it’s known by most people that an LED can also operate as a photodiode. Perhaps some readers are also aware that a reverse biased LED also has a significant capacitance, to the extent that they can be used in some RF circuits in the place of a varicap diode. But how do those two unintentional properties of an LED collide? As it turns out, an LED can also behave as a light dependent capacitor. [Bornach] has done just that, and created a light dependent sawtooth oscillator.

The idea is simple enough, there is a capacitance between the two sides of the depletion zone in a reverse biased diode, and since an LED is designed such that its junction is exposed to the external light, any photons which hit it will change the charge on the junction. Since the size of the depletion zone and thus the capacitance is dependent on the voltage and thus the charge, incoming light can thus change the capacitance.

The circuit is a straightforward enough sawtooth oscillator using an op-amp with a diode in its feedback loop, but where we might expect to find a capacitor to ground on the input, we find our reverse biased LED. The video below the break shows it in operation, and it certainly works. There’s an interesting point here in that and LED in this mode is suggested as an alternative to a cadmium sulphide LDR, and it’s certainly quicker responding. We feel duty bound to remind readers that using the LED as a photodiode instead is likely to be a bit simpler.

This project is part of the Hackaday Component Abuse Challenge, in which competitors take humble parts and push them into applications they were never intended for. You still have time to submit your own work, so give it a go!

Continue reading “2025 Component Abuse Challenge: An LED As A Light Dependent Capacitor” →

An LED Sphere For Your Desk

September 27, 2025 by Lewin Day 1 Comment

The Las Vegas Sphere is great and all, but few of us can afford the expense to travel to out there to see it on the regular. If you’re looking for similar vibes you can access at home, you might enjoy the desk toy that [AGBarber] has designed.

The scale is small — the sphere measures just 98 mm (3.6 inches) in diameter — but that just means it’s accessible enough to be fun. The build is based around various sizes of WS2812B addressable LED rings, and contains 120 individual RGB LEDs in total. They’re wrapped up in a 3D printed housing which does a great job of diffusing the light. Transparent filament was used to print parts that light up with a richly-saturated glow with few visible hotspots. Commanding the LEDs is an ESP8266 microcontroller in the form of a Wemos D1 Mini, which provides plenty of grunt to run animations as well as great wireless connectivity options. [AGBarber] relied on their own Pixel Spork library to handle all the cool lighting effects. Files are on GitHub for the curious.

Maybe you don’t like spheres, and icosahedrons are more your speed. Well, we’ve featured those too—with 2,400 LEDs, no less.

Continue reading “An LED Sphere For Your Desk” →

2025 One Hertz Challenge: Blinking An LED With The Aid Of Radio Time

August 14, 2025 by Lewin Day 3 Comments

If you want to blink an LED once every second, you could use just about any old timer circuit to create a 1 Hz signal. Or, you could go the complicated route like [Anthony Vincz] and grab 1 Hz off a radio clock instead.

The build is an entry for the 2025 One Hertz Challenge, with [Anthony] pushing himself to whip up a simple entry on a single Sunday morning. He started by grabbing a NE567 tone decoder IC, which uses a phase-locked loop to trigger an output when detecting a tone of a given frequency. [Anthony] had used this chip hooked up to an Arduino to act as a Morse decoder, which picked up sound from an electret mic and decoded it into readable output.

However, he realized he could repurpose the NE567 to blink in response to output from radio time stations like the 60 KHz British and 77.5 KHz German broadcasts. He thus grabbed a software-defined radio, tuned it into one of the time stations, and adjusted the signal to effectively sound a regular 800 Hz tone coming out of his computer’s speakers that cycled once every second. He then tweaked the NE567 so it would trigger off this repetitive tone every second, flashing an LED.

Is it the easiest way to flash an LED? No. It’s complicated, but it’s also creative. They say a one hertz signal is always in the last place you look.

Continue reading “2025 One Hertz Challenge: Blinking An LED With The Aid Of Radio Time” →

2025 One Hertz Challenge: Abstract Aircraft Sculpture Based On Lighting Regulations

August 12, 2025 by Lewin Day 9 Comments

The 2025 One Hertz Challenge is really heating up with all kinds of projects that do something once every second. [The Baiko] has given us a rather abstract entry that looks like a plane…if you squint at it under the right conditions.

It’s actually quite an amusing abstract build. If you’ve ever seen planes flying in the night sky, you’ve probably noticed they all have similar lights. Navigation lights, or position lights as they are known, consist of a red light on the left side and a green light on the right side. [The Baiko] assembled two such LEDs on a small sliver of glass along with an ATtiny85 microcontroller.

Powered by a coin cell, they effectively create a abstract representation of a plane in the night sky, paired with a flashing strobe that meets the requirements of the contest. [The Baiko] isn’t exactly sure of the total power draw, but notes it must be low given the circuit has run for weeks on a 30 mAh coin cell.

It’s an amusing piece of PCB art, though from at least one angle, it does appear the red LED might be on the wrong side to meet FAA regulations. Speculate on that in the comments.

In any case, we’ve had a few flashers submitted to the competition thus far, and you’ve got until August 19 to get your own entry in!