Project of a simple wire break or burglar alarm using 555 IC. The circuit is very simple and using not more three parts which are a 555 timer IC, a 100K resistor and a buzzer or relay. The circuit can be used for variety of other purposes when a wire break switch or alarm is required.
A simple thin enameled wire can be used as a sensor between the two points which are point "A" and point "B" and length of the wire can be many meters long and can be wrapped around any place for example doors, cupboards etc. When the wire break or cut from any place the buzzer or relay connected at the output of the IC will become activated.
The two figures of the circuit are shown below, in figure 1 a buzzer is connected at the output of the IC. The output current of the 555 timer IC is not more than 200mA therefore we cannot drive any high current buzzer or alarm directly with it. But by using a relay switch you can switch on any type of buzzer, alarm or device.