[EricH]

Here's a simple test: Set up the rangefinder (the proper name, BTW) at one end of a tape measure, attached to your controller, which is printing out the readings from that sensor to a screen. Put a target at some short distance, say 6", and note what the reading is. Move the target to some other distance within range and note the reading then. That will give you a couple of calibration points. Repeat as needed (you want several points), and plot all the points. You should be able to generate an equation for distance based on reading. Then all you need to do is use that equation in your code.