This circuit was found in an English documentation from the 90s. It uses a PLL CMOS 4046 and is powered by a 9 V battery. The sensors are two electrodes that must be held by the person.
Here is an interesting game found in a 1992 technical documentation. In this game, a set of 9 red...
This circuit was found in a 1969 EEE. The circuit uses transistors from the era that can be...
A frequency divider for digital signals can be constructed based on a single 4018 integrated...