Energy Harvesting Wristwatch Uses a Versatile Photodiode

There’s some interesting technology bundled into this energy harvesting wristwatch. While energy harvesting timepieces (called automatic watches) have been around for nearly 240 years, [bobricius] has used parts and methods that are more easily transferable to other projects.

Unlike early mechanical systems, this design uses the versatile BPW34 PIN photodiode (PDF warning). PIN photodiodes differ from ordinary PN diodes in that there’s a layer of undoped ‘intrinsic’ silicon separating the P and N doped layers. This reduces the utility of the diode as a rectifier, while allowing for higher quantum efficiency and switching speed.

They are typically used in the …read more

Paul Jacob Evans

Thermal Panorama One Pixel At A Time

Inspiration can strike from the strangest places. Unearthing a forgotten Melexis MLX90614 thermopile from his  ‘inbox,’ [Saulius Lukse] used it to build a panoramic thermal camera.

[Lukse] made use of an ATmega328 to control the thermal sensor, and used the project to test a pair of two rotary stage motors he designed for tilt and pan, with some slip rings to keep it in motion as it captures a scene. That said, taking a 720 x 360 panoramic image one pixel at a time takes over an hour, and compiling all that information into an intelligible picture is no small …read more

Paul Jacob Evans