brainwagon

A novel microprocessor interface circuit is described which can alternately emit and detect light using only an LED, two digital I/O pins and a single current limiting resistor. This technique is first applied to create a smart illumination system that uses a single LED as both light source and sensor. We then present several devices [...]

Today’s example comes from the amsat-bb mailing list. I am a member of AMSAT and a subscriber to the amsat-bb mailing list because it’s an interesting subject that I desire to learn more about and that I enjoy sharing with my fellow hams. But AMSAT is seemingly in a struggle to save itself from extinction, [...]