Encoders notes

End stops

To know the position of a motor shaft, consider the following 3D printer. When does it *know* the bed reached it’s end?

Incremental Encoders

If we want to know in more detail the position of a motor shaft, consider a spinning disc and an infrared sensor. How many pulses will we read for a 360 degrees turn?


Quadrature position encoders

By adding another sensor, we can also measure the direction of the motor. Clockwise or Counter- clockwise.


Higher position can also be achieved when using quadrature encoders:



Absolute position encoders


Gray encoder

A researcher invented a simple but useful solution to noise in encoders. Here you can find an extract from Gray’s Patent:



gray-decimal gray