Function needed to save a certain buffer every x seconds automatically

[AW <alexander.willand@t-online.de>]

Hello!

To get a fast refreshing PDF of my LaTeX file, I use latexmk, which renders a 
PDF every time the LaTeX file changed on the hard disk.

I'd like to have a mechanism to save the LaTeX file every x seconds.

I found this solution:

(require 'auto-save-buffers)
(run-with-idle-timer 1 t 'auto-save-buffers)

If I put that into my .emacs, Emacs saves every buffer immediately after a 
change of the buffer. 

But it is cumbersome to switch that off in the .emacs file, if not needed, and 
on, if needed. Could someone write a function to switch this  line

(run-with-idle-timer 1 t 'auto-save-buffers)

on and off? 

Thank you!

Regards,

Alexander