Range Finder with Laser pointers

[aratti]

First of all you need to convert the pot resistance into degree (your angle theta). To do that use, you can use few points as:

90 degrees position = Ohms
60 degrees position = Ohms
45 degrees position = Ohms
30 degrees position = Ohms
0 degree position = Ohms

Use the above value to find the regression curve (use excel) . If the regression is acceptable then you have the formula for converting your Ohms value into degree, if not you will need a lookup table.

Once you have the degree value of the angle of your laser pointer #1 (theta), extract the tangent and do this simple math: Segment B = Segment A/tan (theta)

If you will suceed in getting the hypotenuse (as suggested by scalerobotics) then

Segment B = SQR(( hypotenuse * hypotenuse) - (Segment A * Segment A))

Cheers

Al.