Brushless DC Rotor Position Question

benjaminbailes

Hi. I am curious about ways to sense the position of a rotor in a BLDC motor. I am familiar with hall sensors and back emf but am wondering if there are other ways to find the position of a rotor maybe more accurately.

I had an idea about using a laser and a photoresistor around the circumference of the stator that would use the varied resistance to give a voltage reading to a microcontroller that could be used to find the position. Maybe I'm way off with that one I can see some problems like heat from the motor messing with the resistance. If anyone could give me some suggestions on what's out there I would appreciate it.

I_am_learning

They are called rotary encoders.
http://en.m.wikipedia.org/wiki/Rotary_encoder#section_5

benjaminbailes

Thanks for the tip

Turst

Resolvers are also useful for absolute position.