You can use 2 square magnets placed opposite, can be no the best setup but work.

The drawing scheme is similar to "Bic HALL":

http://simhq.com/forum/ubbthreads.php/topics/3225807/DIY_hall_sensor.html

Today are accessible HALL sensor assembled like a pot - that make DIY uninteresting in some cases.

http://www.bitechnologies.com/pdfs/6120.pdf

http://uk.farnell.com/bi-technologies-tt...0deg/dp/2319661


Last edited by Sokol1; 06/04/16 01:31 AM.