Let's Make Robots!

LDR and IC logic gate

I have a basic LDR circuit 

Looks like this one except there is no pot >>> http://www.reuk.co.uk/Light-Dependent-Resistor.htm (the 1st figure)

I have 2 of them and I want to logically or them together.. The problem is I dunno where to connect the IC i tryed connecting it to the legs of the LED and transistor but i don't get the desired output.

the truth table became like this

(the input is the LED output of the LDR circuit and not if i put the light on the LDR)

Follow You...

I want to make a robot that follows you but it is stationary in position ... it can only rotate on it's axel to follow you... I figured a servo can be used to make the 360 degrees turn but then i read it can only get until 200 degrees... As for the the sensor I search and found that i can use a PIR sensor(motion sensor) or a color sensor (which is more preferred?)... I'm am less than clueless on how to make use of the sensor so that the robot will follow you.. The motion sensor will sense you moving but i don't know how to make it follow you