This burglar alarm is designed using 555 timer. This circuit is mainly used in homes and offices for security purpose. This circuit is designed to alert the user when an intruder enters into the home.

Cedar Crest High School senior Tyler Steffy was in his first-period class Thursday when the alarm no student wants to hear started ringing in his classroom — “red alert, intruder.” At first, Tyler and ...

Ultrasonic Burglar Alarm: Transmitter and receiver parts of the circuit are connected each other by using a triple cable. System operates with 20V supply and 10V effective output voltage drives the ...

An intruder alarm at a Delaware County school triggered a lockdown and large police response in Broomall, authorities said. Officers were dispatched to the Delaware County Intermediate Unit (DCIU) at ...