Hi Guys,

I am trying to build my first robot. The thread with more information on it is actually on a different board here.

With the help of this thread, I came up with this diagram:

(Also attached)

I found that when I have the LCD backlight on, the display flickers a lot when I have the IR sensor connected as well.

Can someone tell me if the voltage regulator would help with the flickering? Or is it overkill and should I rather just use bypass caps?

Hope someone can point me in the right direction.

 

Well, your grounds look correct. Maybe the correct question is: can an L7805 (not the same as a 78L05) supply a serial LCD with backlight? That part number is misleading! Everybody else uses the "L" designation as a 100 ma limit chip. The L7805 can do a whole amp (with proper heatsink).

and, your regulator chip needs capacitors to stop it from oscillating. I don't see them on the schematic.

I don't know. How much current does a serial LCD display use?
How much current can a GP2Y0A21YK provide?
How many datasheets should you provide to get a proper answer?