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 :smiley-confuse:
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.
Google 240Vac input optocoupler
put your mains voltage figure where 240 is if yours is different.
If you control the switches why do you need to check the state?
The remote should talk to the controller, not bypass it.