i need to check status of the appliances?

[anbu123]

my project is to control home appliances(fan, light, motor, tv, fridge etc) through controller using relays. i want to extend that to 2 way switch, means by manual n using remote(controller-atmega 328) also.

i am not getting way to check status of appliances whether is on or not by controller.
thought to use stepdown trans. but its too expensice because i have to use separate trans for each appliances
So give me some ideas to check status of the appliances

[septillion]

Why everything in bold? Please don't try to scream and edit your post.

And why are you adding a mains switch to the system then? Just use a switch as an input to the Arduino and make it also toggle the corresponding output. That's easier then adding a 2-way switch. And if you say a 2-way switch is more fail safe that is barely true. The ONLY way that's fail safe is if the Arduino does nothing at all. But a bug that interferes with the 2-way switch (because of the feed back) is as likely making it NOT fail safe by default.

And if you really want to check mains, use a opto coupler (and a bridge rectifyer and current limiting). BUT it will consume energy. If you use only resistors to drive the opto at only 5mA that will be ore then 1W (@230V). You could use a capacitive dropper to drive it but that will add reactive power to the system aka messes with the power factor. And n both cases, you DO mess with mains so make sure you have proper isolation etc. Not really something for a prototype PCB.

[TomGeorge]

Hi, 

Google    240Vac input optocoupler


put your mains voltage figure where 240 is if yours is different.

Tom...

[MarkT]

If you control the switches why do you need to check the state?

The remote should talk to the controller, not bypass it.