The two types of LED candle, side by side.

2025 Component Abuse Challenge: Heat Activated LED Candles

[Miroslav Hancar] wasn’t satisfied with abusing just a single component for our Component Abuse Challenge. He decided to abuse a whole assembly, in particular, some LED candles.

In this project, LEDs are abused as temperature sensors. When the temperature gets hot enough for long enough, the microcontroller will turn on its LEDs. How? A diode’s forward voltage is temperature-related. By monitoring the forward voltage, the microcontroller can infer the temperature and respond appropriately.

This particular project is really two projects in one, centered around a common theme, heat activation. The first version has four LEDs and, in response to heat, four LEDs flicker to simulate a real candle. The second version is also heat-activated, but it has only one LED. You can snuff out this LED by pinching the top of it with your fingers. You can see a demo of each version in the videos below.

Continue reading “2025 Component Abuse Challenge: Heat Activated LED Candles”

Hackaday Prize Entry: Lighting The Way For Walkers

Chances are, you probably know someone who uses a walker to assist in their mobility. Ever wonder about how they could be made better? When [Alan McFarland] noticed his friend using his iPhone as a light to walk down a hallway — with only one hand on his walker — he realized something could easily be done to make the walker more functional. His own light bar.

Sure you could get a flashlight, zip tie it to the walker, or maybe a bike light with a dedicated mount — but [Alan] wanted it to be a bit more elegant; and functional. With this in mind, he attached an LED light strip to the lower frame of the walker to help illuminate the path ahead. A button is wired up to the handle for easy access, and he’s even using a PIC12F1501 microcontroller to give it some logic — it’ll turn off by itself, fading out, giving the person a chance to sit down before the lights go out.

The thing we like about this project is he programmed it using the PICBASIC PRO compiler — the same compiler that [Alan] himself used nearly 20 years ago programming the Borg suits and spacesuit lighting on Star Trek: First Contact — how’s that for a random trivia fact!

The 2015 Hackaday Prize is sponsored by: