This is one of the modules that’s for some reason is the most popular by my friends.
It’s based on a voice recognition module from Sensoryinc . It’s not really voice recognition, but just learn the module first for example the word “light” with your voice and if you then say “light” it will recognize this and will give a command.
Every command has first the key word and then the command word, this to prevent accidentally triggering one of the commands.
The module is not made anymore, so for the future I must look for something else.

 

 

Demonstration video, switch on the light

Voice recognition demo