Multiple hall effect sensors in proximity

Question

I'm interested in using a linear Hall effect sensor to measure displacement varying by about 1.5 inches. The idea is I have a piston with a magnet at the end and a Hall sensor at the end of the cavity to output a voltage roughly proportional to the proximity of the magnet.

Question is, what if I have several of these pistons side by side? They need to be less than half an inch apart. Will they interfere? I understand that the Hall sensor is only sensitive to magnetic field lines perpendicular to it. Does that mean that the magnetic field from a magnet displaced half an inch away horizontally will not register a voltage?

Thanks guys.

Answer 1

There are two ways of knowing this. Mock it up and try it, having a variety of magnets of known strength around to try it with, or looking up the equations, grunting it out, figuring out the strength of the magnet you need, and ordering some sizes around that, then try it as above.

Most if not all of the equations you need will be on the Web pages of Hall Effect parts makers like Allegro. You might also check out Wolfram Alpha.