Actuator with zero point initialization

An electronic system, comprising:

• a shaft having:
• a resistance portion, and
• a substantially uniform portion;
• a motor configured to rotate the shaft, the motor outputting a current signal to indicate current level supplied to the motor;
• an interference portion disposed on a member adjacent the shaft, the interference portion configured to facilitate a resistance to shaft rotation when the shaft rotates, the resistance to shaft rotation eliciting a magnitude of the current signal to be greater when the resistance portion passes in front of the interference portion than when the substantially uniform portion passes in front of the interference portion;
• and
• a controller configured to (i) receive the current signal from the motor, (ii) selectively identify four different magnitudes of the current signal, and (iii) send a motor control signal to the motor.

An electronic system, comprising:

• a first shaft having:
• a resistance portion, and
• a substantially uniform portion;
• a second shaft attached to the first shaft at a shaft interface;
• a motor configured to rotate the first shaft and the second shaft, the motor outputting a current signal to indicate current level supplied to the motor;
• an interference portion disposed on a member adiacent the first shaft, the interference portion configured to facilitate a resistance to shaft rotation when the shaft rotates, the resistance to shaft rotation eliciting a magnitude of the current signal to be greater when the resistance portion passes in front of the interference portion than when the substantially uniform portion passes in front of the interference portion;
• and
• a controller configured to (i) receive the current signal from the motor, (ii) selectively identify four different magnitudes of the current signal, and (iii) send a motor control signal to the motor.

A method for initializing an actuator comprising:

• directing a motor to rotate a shaft having a resistance portion, and substantially uniform portion, the motor outputting a current signal to indicate current supplied to the motor;
• and
• identifying when an interference portion passes in front of the resistance portion;
• and
• causing resistance to rotation of the shaft by engagement of the interference portion with the resistance portion and the substantially uniform portion, the resistance to shaft rotation causing a magnitude of the current signal to be greater when the resistance portion passes in front of the interference portion than when the substantially uniform portion passes in front of the interference portion.