How to customize touchpad disable button in ubuntu 15.10?

Question

linux

I can not make it so that it would be possible to turn off / on the elantech touchpad in ubuntu 15.10 gnome 3.18 with the button.
The touchpad is detected correctly, you can turn it off in the settings.

but you need a button.
Thank you.

Answer 1

askubuntu.com/questions/65951/how-to-disable-the-t...
https://wiki.archlinux.org/index.php/Touchpad_Syna...