Door Openinng ALARM'S application in speed breaker:

speed breaker project:
• Speed Breaker being discussed here is not a normal one as we see in conventional roads.
• It is similar in function but different in operation.the door opening alarm is playing a major role in speed breaker project.
IMPLEMENTING DOOR OPENING ALARM:
• The major drawback of speed breaker project is, under natural disastrous speed breaker gets subjected to very heavy loads which it cant bear and there is no indication about that serious fault
• Inorder to overcome it the door opening alarm circuit is kept at a position just below the shaft of dc generator,so when the speed breaker is been subjected to very heavy load it results in the shaft collapsation of dc generator which makes contact with the door opening alarm circuit.
• Hence door opening alarm circuit is energised and through a buffer it produces a alarm sound indicating the mal function of speed breaker project


DOOR OPENING ALARM
This inexpensive project can be used as door opening Alarm.
A magnet operated reed switch is connected to the circuit operated buzzer.
This switch is kept on corner of frame of door and magnet is fixed on moving part of door using adhesive, as shown below:
When door is closed, magnet comes close to reed switch.
Then reed switch is closed,i.e. terminals are shorted.
Then buzzer does not sound.
When the door is opened slightly, magnet moves away from reed switch.
Then reed switch is opened. As a result alarm is activated.
when door is closed, alarm is automatically switched off.