Introduction to Robotics POV

POV: you are a pulse from a motor encoder

POV: you are a pulse from a robot's motor encoder

Lesson notes

Key points

You are born when a slot on the spinning encoder disk lets light hit a photodetector, flipping the output high.
You race beside a twin channel shifted a quarter cycle, and whichever of you arrives first tells the controller the direction.
The microcontroller counts you, and the count divided by counts per revolution becomes the joint angle.
Finally you become the measured angle that the controller compares with the target to compute the next motor command.

Takeaway: Encoder pulses counted over CPR give angle; A/B phase gives direction.

Quick check: How does a quadrature encoder detect the rotation direction of a shaft?

From pulse brightness
From A/B phase order
From pulse width alone

Channels A and B are 90° apart; which one leads gives the direction.

Optical diskQuadrature A/BCounter registerClosing the loop

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