Automatic Door Alarm Circuit

One of them can put in front of the locker while another one can be placed on the front door.

Automatic door alarm circuit.

It will produce a beep sound when each new customer or visitor is entering and will automatically switch off after few seconds. For sensing the door position different types of methods can be used such as magnetic light beam mechanical electrical etc. Presence of north polarity magnetic field generates a low voltage at the output of the sensor. When the door is closed the magnet is close to the sensor.

As a result pin 4 of ne555 also goes low and the timer does. The schematic for the door alarm circuit is shown below. And the alarm remains on as long as the door is kept open. Ne555 is wired as an astable multivibrator whose reset pin 4 is controlled by the sensor output.

The door opening alarm circuit or front office visitor alert is used for alerting you when a customer is at your office shop. The 9 volts that are supplied to this circuit are in parallel with the 10kω resistor and the knife switch with the gate of the scr being. Door open alarm circuit. S1 and s2 are the two switches that are used in the circuit so that both can be put in two different places i e.

Schematic of the door opening alert circuit. Door alarm circuit circuit. We will use a knife switch in conjunction with a 10kω resistor the 2 of these components form a voltage divider circuit.