help with sound sensors

actually i am thinking of doing a project using sound to operate tubelights and fans
please help me with the circuit.the circuit should be complete only if we say"light on" or "fan on"
where should i start with?

What you want to do is not easy and has taken many decades of research for engineers to solve and they still aren't fully there.

Fortunately you can buy ready-build speech recognition modules but you still need some electronic and programming knowledge to use them.
Try Googleing for voice or speech recognition module.

**broken link removed**