Automatic AC Power Switch

Electrical appliances accidentally left on  in (holiday) homes left unoccupied for a  brief or a protracted length devour power  unnecessarily and may existing a fire hazard. Everyone shall be accustomed to those  nagging thoughts, a quantity of miles down the  highway from the home: “Did I remember  to change off the espresso machine? The  milds? The oven?” 

Circuit diagram :

Automatic AC Power Switch Circuit Diagram

Hotel rooms are regularly equipped with a  swap near the main door which allows the facility supply to the entire thing in  the room simplest when the plastic card (which  may contain a chip or have a magnetic strip  or a sample of holes) that serves because the room  secret's inserted. The circuit thought given here  to modify off gentles and different home equipment is  alongside the identical lines. The answer is distinctly easy. 

A reed contact is suited for the body of the main entrance door, and a matching magnet  is hooked up to the door itself such that when  the door is closed the reed contact is also  closed. To allow power to the house, press  S1 briefly. Relay RE1 will pull in and complete  the circuit for all of the AC powered home equipment in  the house. The relay will be held in even after  the button is liberated by means of the second relay contact and the reed contact (‘latching’ function). 

As quickly as the primary entrance door is  opened, the reed contact may even open.  This in flip releases the latch circuit and  consequently the relay drops out. The  various linked home equipment will thus  routinely and that inevitably be switched  off as quickly as the house is left. The circuit is mainly designed for  small vacation properties, where this mode  of operation is especially sensible. Of course, for any circuit that deals in AC  powerline voltages, we should mention  the next caution. 

Caution:

shock hazard! Construction and connection of this circuit  will have to simplest be carried out by suitably-qualified  personnel, and all applicable electrical safety  rules must be observed. In particular, it  is essential to be positive that the relay chosen is  acceptable to be used at domestic AC grid volt-ages and is suitably rated to hold the required  current.

http://www.ecircuitslab.com/2012/04/automatic-ac-power-switch.html