Hot resistors used for color-changing clock face

[Sprite_TM] built a full clock display using thermochromic paint. This picks up where he left off with his paint-based 7-segment display prototype. He never really saw that design through to a finished project, but he recently came across the leftover paint and decided to do something with it. Instead of making thin traces on a PCB he’s heating up resistors mounted on protoboard. Each resistor has been coated with the black/light grey paint after getting a rough sanding on the tops of the packages. Run around 500mW through a segment and they heat up enough to change the paint to light grey. Once shut off, the segments gradually fade over the next 60 seconds.

Power All Over Your Body

We know that you can transform the mechanical motions of your body into electrical energy, like when you turn the crank or shake a mechanically-powered flashlight. These types of mechanical motions are quite large compared to many of the day-to-day (and minute-to-minute) actions you perform–for example walking, breathing, and thumb wrestling.
What if we could harvest energy from these tiny movements? Researchers at the Korea Advanced Institute of Science and Technology are seeking the answer to this question with piezoelectric barium titanate. The electrical output of their devices is very small (in the nanoAmps) but over a long period and over many repetitions it would be possible to run a small electric device–even a biologically-embedded one. An alternative to blood power?
There is clearly a lot of potential in this technology, and we’ll be interested to see if and when we can start messing around with this stuff. Heck, it’s already been used to power a small LED and you all know just how much everyone would jump at the chance to cover themselves in self-powered LEDs…