The tilt alarm circuit is mainly used for security purposes and can be used where it needs a security for tilting. It can also be used in auto mobile security. When a car or bike is tilted the circuit sounds.
K2 is the Tilt sensor. When the connected equipment is tilted, the two leads of K2 gets shorted. When there is a short, VT1 gets triggered and and it simultaneously triggers VT2 and IC1. IC1 works as a Astable Multivibrator and it makes the Loudspeaker to sound. The Astable multivibrator clock frequency is found using the formula given below the circuit.