How to Toggle disable/enable Keyboard and touchpad

Hi,

I like to do maths exercises from online portal; so i keep my exercise book on the palmrest of my laptop and practise. But it presses keys and touchpad clicks. I use a external mouse to scroll the web page.

So I need a small utility which will allow me to disable/enable the built-in keyboard and touchpad only, with a mouse click.

Is there anything that can suffice my need?

I'm using dell inspiron 7537 with win8.1.