In the figure we have one of the many ways to program the counting of a 4017. The circuit uses additional gates and was found in the Radio Electronics magazine of April 1989.
This circuit uses two sensors that are placed at the intersection of a miniature railway, causing...
This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response...
Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990....