Disable Screen Sleep/Dimmed on Raspberry Pi 3810
The default setting of raspberry pi with raspbian OS is it will dimmed or sleep screen in certain time, in fact is not necessary if we use raspberry pi in KIOSK mode.
To disable screen dimmed/sleep, it's easy to edit file /etc/lightdm/lightdm.conf
sudo nano /etc/lightdm/lightdm.conf
And then uncomment or add this line to the file.
xserver-command=X -s 0 dpms
Now you sreen will stay on