I think the problem you may have is that anything above just a very low rpm, the LED's are going to blur together, due to the speed and the persistence of a LED.
I put together a simple phase rotation detector and pole counter circuit for BLDC/AC servos and I can turn this by hand to get the read out, If I just spin the motor even slightly, it is impossible to distinguish between pulses, and this is only for 1 to 4 pulses for one revolution of the motor for a 2pole/8pole motor span.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.