Im gonna need a bit more details, what model of IR sensor? i can't visualize what you're saying, and how do you wire to EZ-B? example of script would help too or just post a EZB file if easier for you.

on the sensor is this one

sharp gp2d15 then since you are using a wall-e need to change to the lowest 10cm setting

adjusting sharp gp2d15 IR SENSOR

SCRIPT NEED TO WORK ON IT,NOT VERY HARD

to use it on wall-e place in about the center on front edge at a angle using a rule so that sensor is about 4 inches (10cm) to the floor reason to set at a angle so the robot will stop in time before fall off a cliff or stairs also on stopping the motors its not STOP you need its BRAKE command

What if I already have the hcsr04 sensor at the bottom of wall-e? Can I mount the ir behind it pointing down 45 degree? Also do i need to mount vertically or horizontally? Also I'm running servos for wheels not motor so I think stop script will work.

horizontally,widest distance,vertical is for wall corners and like small detection ,like a chair leg place behind it ,but make shore it doesnt hit the sensor do you have the sonar facing forward or down to floor,down to floor not great read the post on using sonars and IR sensors

I have the SR04 facing forward for obstacle detection. Basically all I want wall-e to navigate himself without bumping into things and without dropping off a table.

that sounds good,i am doing the same with my WALL-E,but only have it apart,and bought parts working to finish first my orobot roomba project,then brookstone rover project both have up in forum,then omnibot 200 design,bought over 20 robot toys to hack,have 10 EZB and 6 bluetooth camera's

wow looks like you are going to very busy, so many bots so much investment, i got Wall-E, R2D2, Buster, Robie SR, and Omnibot 2000 and i think i have way too much already, need to sell some other R/C heli stuff to recover costs...hehe.

What about this ir sensor? small size, 5ma, good price, perfect range for Wall-E.

www.pololu.com/catalog/product/1134

Still needs help with hook up to EZ-B board and scripting part. What if I want obstacle detection when wall-e goes reverse as well, is this unnecessarily? if not, what do i need?

thats one i am using ,couldnt remember the part # at the time,it does take one screw witch is kinda bad,pololu is where i get alot of parts from,i think i have 8 left from a batch of 25 super simple to hook up one pin is gnd ,one pin is 5 volts,one goes to digital pin for reverse you need one in back of the robot

i also have robbie SR,3 types of R2-D2, 2 types of omnibots,plus rover AR DRONE PARROT ,3 types of RAD robots and alot more