Enabling Dictation Commands with Voice Command

Hello,

I know the Dictation Commands on mac can be activated by a keyboard shortcut, by double pressing fn key.
However, I want to enable Dictation Commands using a voice command, let's say "Ok Mac" for example, the reason for this is because I want to control my Mac when I'm far from the keyboard, let's say switching a sound file while napping! or saving a note while the mac is running but not being in the keyboard reach.

I know how to do the second part of the process through Automator. However, I never came across anything that can enable the Dictation Commands with a voice action.

Is there any app/script/configuration that can allow me to do so?

 

Yes. the voice command should activate the dictation, the dictation does not have to be on before that, until someone say something. The dictation commands is a program that runs using the built in mac microphone, if the microphone is working the dictation doesn't have to be ON.

just like we can do using the voice command "wake up" in Dragon Naturally Speaking, or "Hey Siri" in Siri.

 

So is there any solution to this thread?