the NE555. (Video, embedded below.) The circuit is simplicity itself, just an astable of the type that has made a billion beepers and flashing LEDs. It drives two ultrasonic transducers in ...
The electronic dice that [Tim] has on hand makes use of two main ICs: a NE555 and a CD4017 which is ... but can also be arranged to form logic circuits. This comes at a great cost, however.