How To prevent your pi's screen from going to sleep

If you don't want your screen to shut down try this:

sudo nano /etc/kbd/config

edit these two lines:

BLANK_TIME=0
POWERDOWN_TIME=0

and then, if you realize that this didn't work, try:

sudo nano /etc/lightdm/lightdm.conf

in the section [SeatDefault] insert this line:

xserver-command=X -s 0 dpms

(And: How To prevent yourself from going to sleep: ssh into your pi)