In the kit Cash Box Guard here is a smart security circuit for your cash box that thwarts the theft attempt by activating an emergency beeper.
This kit Cash box guard circuit is built around IC CD4060 IC, which has an inbuilt oscillator and divider. The basic oscillator is configured by a simple resistor-capacitor (R-C) network. IC CD4060 divides this oscillator frequency into binary divisions, which are available as outputs. In light, reset pin 12 of IC remains low, which enables the oscillator built around IC. However, in the dark, it making all the outputs low. This also stops oscillations of the internal oscillator. Working of the circuit is simple. If the cash box is closed, the interior will be dark. Hence in the dark, the light-dependent resistor (LDR) resets IC and it stops oscillating and counting. At the same time, pins 13 and 14 of IC go low. So neither the piezobuzzer sounds, nor the relay energizes, indicating that the cash box is closed