Relay with physical switch

]:D

Hi everyone!

I know how to control an AC lamp with my arduino using a relay and I would like to use this system throughout my house to control different AC appliances. However I would like to leave the original physical switch :p

Do you know how I could combine the two to work together? ex: I turn on the light and once in my sofa, turn it off with my Android phone

Hope you understood! :P :P ^_^ Many thanks!

That's just the same as wiring a light on a stairs so you can switch it on at the bottom and off at the top, with the added spin of one switch being a (edit: spdt) relay.

http://www.electricaltechnology.org/2012/11/stair-case-wiring-circuit-diagram-or.html

Very good idea tranef.

You can use the tip of JimboZA if you want to turn ON and OFF either with the original swtich or with the "phone". But if you want to only turn OFF with the phone if the original switch it's already ON you can put the original switch and the relay in series, like you can see in the link bellow:

http://www.durofy.com/introduction-to-microcontrollers/

After that you can even control the level of light with a thyristor or a triac: http://en.wikipedia.org/wiki/TRIAC http://en.wikipedia.org/wiki/Thyristor

What type of communication between the Arduino and the phone you use? Bluetooth?

But if you want to only turn OFF with the phone if the original switch it's already ON you can put the original switch and the relay in series

And next night? When you enter the room the light switch is still "on" but the light is "off", so to "on" the light you need to "on " the relay. Then the OP's back where he started, with only the relay doing the switching.

With the way I proposed, next night on the way into the room he switches the light on by flipping the light switch, and the light goes off regardless of the fact the relay is still in the position it was left in last night. But of course this way requires SPDT switch and relay, and double wiring in the wall.

Simple series switch and relay will not, I think, meet the OP's needs.

Yes, I agree 100% with you, JimboZA.

I only said what I said for 2 reasons: 1- I believe that is easiest to understand the series switch that the stairs for someone that is new at this world (of electronics); 2-My first thought was the light control switch that must be done with, for example a triac, in the place of this relay.

Then, in series, you can power the Arduino from the original switch and start the relay always "on". Then if the switch is "on", the Arduino is "on" too and it can turn "off" the light with the phone (and "on" back again, etc.), and if switch is "off" the Arduino is "off" and can't turn "off" the relay. The next time that the OP turn "on" the switch the cycle starts again.

luisilva: Yes, I agree 100% with you, JimboZA.

I only said what I said for 2 reasons: 1- I believe that is easiest to understand the series switch that the stairs for someone that is new at this world (of electronics); 2-My first thought was the light control switch that must be done with, for example a triac, in the place of this relay.

No. If you're using a triac, you place it in the common line to the relay. That way, you can dim the light whichever way the relay is set.