I have some questions in which I do not understand what to do , suppose there is a house oand ut has 10 lights as I have shown in the diagram. I want to control each light from my mobile APP so I want to design system for this puropoes

I found that one raspberry pi is enough to control 10 lights with suitable relay modules . I do not understand whether the relay modules should be kept in different rooms or all relay modules should be kept in the same room with Raspberry Pi?

 

It is possible to do it either way but it would be much easier and safer to run wires for a relay at each location rather than to re-wire the power for the lights. Either way, it is going to be a big job to pull all those wires without destroying your ceilings and walls.
Have you considered using Wi-Fi light switches in the rooms? You could control them directly with a phone app.
Regards,
Keith

 

I agree with Keith. I use lots of Phillips Hue Bulbs and Wemo switches/dimmers. All have great apps and also integrate into Google Home and Alexa.

 

I want to design system for this puropoes

Why bother when you can buy something inexpensively?

I started using X-10 in the early 90's and have stayed with it. They have an interface that can be controlled from a smartphone. I think I bought it and never got around to using it.

I have a computer programmed control module that turns things on and off at certain times, and I have remotes located in several rooms so they can be controlled "manually".

If you really wanted to design something, you should use WiFi. I can control my water heater from my phone, but the app is quite dumb and can only change temperature, set/remove vacation mode, and detect leaks. I wanted to be able to have a schedule of vacation times so I can turn it off when hot water isn't going to be used and on a little while before hot water will be needed.