Make: More Electronics

Chapter 26. Experiment 26: Running Rings

A ring counter is a type of counter that has “decoded outputs.” This means that it activates one pin at a time, beginning with the pin that represents 0 and continuing up to a value that is limited by the number of pins. After that, the cycle automatically repeats.

By comparison, a binary counter has “coded outputs.” In other words, the high and low states on its output pins represent a number in binary code.

The ring counter that I will be using here is the 74HC4017, which can also be described as a decade counter, meaning that it can count up to 10 (actually, from 0 through 9). I plan to apply it in two different reflex-testing games: one that flashes LEDs sequentially, and another that flashes them randomly. ...