Power screwdriver having rotary input control

A power tool comprising:

• a housing;
• an output member at least partially contained in the housing and configured to rotate about a longitudinal axis;
• a motor contained in the housing and drivably connected to the output member to impart rotary motion thereto;
• a rotational motion sensor arranged in the housing and operable to detect a user input, the user input comprising a rotational motion of the housing in a desired rotational direction about the longitudinal axis of the output member;
• and
• a controller configured to receive a signal indicative of rotational motion from the rotational motion sensor and operates to determine a direction of the rotation motion of the housing about the axis from the signal, the controller operably connects to the motor and, upon detecting rotational motion of the housing, operates to drive the motor in the same direction as the detected rotational motion of the housing.

A method for calibrating a rotational motion sensor disposed in a power tool having an output shaft, comprising:

• arranging a rotational motion sensor from a longitudinal axis of the output shaft in the power tool, where the rotational motion sensor outputs an analog signal indicative of rotational motion about the longitudinal axis;
• determining, by a controller in the power tool, when the power tool is stationary;
• determining, by the controller, an error in the analog signal received from the rotational motion sensor while the power tool is stationary;
• calibrating the rotational motion sensor using the error;
• monitoring, by the controller, rotational motion of the power tool about the longitudinal axis of the output shaft using the rotational motion sensor;
• determining, by the controller, a direction of the rotational motion about the longitudinal axis;
• and
• driving the output member in a clockwise motion about the longitudinal axis when the rotational motion of the power tool about the longitudinal axis is clockwise and drives the motor in a counter-clockwise motion about the longitudinal axis when the rotational motion of the power tool about the longitudinal axis is counter-clockwise, where the output member is driven by a motor residing in the power tool.