somebody tell me how to do this special vibrato pedal

[vibrato]

double expresion pedal, left for speed and right for note range. (up: nothing, middle: semitone , down: whole tone vibrato) based on whammy but without changing the timbre. To be used in all plugged instruments including voice. is there's anyone able to build it i'd pay for one if it works as to emulate the changing tuned vibratos of maria callas.

[blackieNYC]

I love it! First post includes Maria Callas sounding pedal!  And a wacky pedal-do you mean two up-n-down expression pedals beside each other, or a side-to-side-and-up-and-down like this zoom thing?
http://www.zzounds.com/item--ZOMG5
And there's this DeArmond

Mechanically challenging

Welcome!

[deadastronaut]

some kind of joystick setup might work...

as blackie says though, mechanically challenging...

[alfafalfa]

What I hear is a tonecontrol when his foot slides sideways.
Fender used to have these pedals I believe.

[teej212]

Would be easy to do digitally ie fv-1

[StephenGiles]

This is the original version of The Storm by The Hunters. I believe this group backed Cliff Richard a few times when The Shadows were not available.

https://www.youtube.com/watch?v=m429iA5KS1E