I am trying to set-up a system where I'll have four ultrasonic sensors, one on each wall of an square room, to track the location of a person walking around in that room. I am wondering if I could use something like this parking sensor...http://cgi.ebay.ca/Parking-Reverse-Sensor-System-with-Audio-Colour-LCD_W0QQitemZ260095933638QQcategoryZ60203QQtcZphotoQQcmdZViewItem#ebayphotohosting
...and somehow modify it to send information to the arduino. Would the code for using multiple ultrasonic sensors to track this kind of movement be ridiculously hard to figure out? Are there any other methods that might be easier/more efficient to accomplish this x,y coordinate without having to have the person carry around any sort of sensor on them?
Thanks for any help,