Beeps when hears your whistle
A gadget suitable for key-holders, games etc. These devices contained a special purpose IC and therefore were not suited to home construction. The present circuit is designed around a general purpose hex-inverter CMos IC and, using miniature components and button clock-type batteries can be enclosed in a matchbox. It is primarily a gadget, but everyone will be able to find suitable applications.
This device beeps intermittently for about two seconds when a person in a range of around 10 meters emits a whistle.
The first two inverters contained in IC1 are used as audio amplifiers. IC1A amplifies consistently the signal picked-up by the small elec