Description:I am building a Home Automation project....This project's main implementation are CAN & RC5 protocol.In a home i am installing single node for each room.Node to Node communication will be done through CAN protocol and User to Node is done through RC5 protocol.All my coding and testing part is 80% done....

My Problem:As every room already has pre-installed electrical switches...then what kind of circuit or technology should be applied there so that i can control every electrical & electronics equipment using my projects relay panel as well as with those electrical switches.

Is there any circuit or technology ????????? Please help me......

I hope you great hearts will understand my problem and reply soon.

Thanx in advance...

 

I assume your room switches are SPST. Since your room switch can be either open or closed and you want to control the power to your load independently of the position of the room switch you will need 1 relay contact in series and one in parallel with the said switch. The one in series controls the power when the room switch is closed, the one in parallel when it's open.

You will need to measure the voltage over the room switch to know it's position (with a small transformer for example)

Much easier: Replace the room switch with a SPDT switch and use the same kind of contact for your relay: