Turning PC On with a Knock using ATtiny45

by Joonas Pihlajamaa @ codeandlife.com: Today’s post is something I’ve prepared for a long time. Hardware-wise it’s a simple thing – ATtiny45 emulating a PS/2 device, sending a keypress when three knocks are detected in the attached piezoelectric sensor (or piezo buzzer as they are also called). But if your computer can...