Emulating screen zoom keyboard shortcut

I’m attempting to control the accessibility screen zoom functionality in OS X via an external pedal; however, trying to fake the keyboard ctrl key press and mouse scroll wheel seems to not trigger the zoom functionality.

Some simple python that I’d expect to zoom the screen, does not.

Code Block
import pyautogui
pyautogui.keyDown('ctrlleft')
pyautogui.scroll(10)
pyautogui.keyUp('ctrlleft')
pyautogui.keyDown('ctrlleft')
pyautogui.scroll(-10)
pyautogui.keyUp('ctrlleft')


Any assistance controlling the screen zoom level from an external source either via faking the keyboard and mouse or otherwise, would be greatly appreciated.
Emulating screen zoom keyboard shortcut
 
 
Q