This TV remote control receiver uses a ratchet system to activate an old drum-type selector to change channels. A common system at the time. The circuit is from a Radio Electronics from February 1961.
This circuit is from a Popular Electronics from the 90s. The integrated circuit admits equivalents...
This very interesting project was obtained in a 1980 publication. It consists of a device that is...
This circuit beeps when the sensor is triggered by the opening of the freezer door or other...