Precision in Motion: The Role of Hall Effect Sensors in Curtain Motor Positioning

How do smart curtains know their exact position? We explain the use of Hall effect sensors for closed-loop feedback, enabling precise calibration, soft start/stop, and travel limit setting.

: hall effect sensor curtain motor, motor positioning feedback, smart curtain calibration

A basic motorized curtain might simply run for a pre-set time to open or close, a method prone to error from voltage fluctuations or load changes. Premium systems achieve repeatable, precise positioning through closed-loop feedback, most commonly implemented using Hall Effect Sensors.

A Hall effect sensor detects the presence and strength of a magnetic field. In a brushless DC motor, these sensors are embedded in the stator. As the permanent magnet rotor spins, the sensors detect the changing magnetic fields, allowing the motor's controller to:

1. Precisely determine the rotor's position to commutate the windings at the exact right moment.

2. Calculate the motor's speed and distance traveled.

By counting the number of magnetic pole changes, the controller can calculate how far the curtain has moved along the track. This is how the system "knows" when it has reached 50% open or a user-defined limit.

This feedback enables critical features:

• Soft Start/Stop: The controller can ramp the motor speed up and down smoothly, reducing mechanical stress on the system and preventing the curtains from "jerking."

• Absolute Positioning: The curtains can be commanded to move to any specific point (e.g., "open to 25%") with high repeatability.

• Obstacle Detection: If the motor's torque increases suddenly (indicating an obstacle) while the Hall sensor data shows it has not moved the expected distance, the system can trigger a safety reversal.

Precision engineering matters. Our motors utilize multi-pole Hall effect sensors for high-resolution positional feedback, enabling flawless automation and safety features. In