Rotational sensing for a replaceable unit of an image forming device

A replaceable unit for an electrophotographic image forming device, comprising:

• a housing having a reservoir for storing toner;
• a rotatable shaft positioned within the reservoir;
• an agitator mounted on the shaft;
• a drive element exposed on an exterior of the housing unobstructed to receive rotational force when the replaceable unit is installed in the image forming device, the drive element operatively connected to the shaft to rotate the shaft upon receiving the rotational force;
• a sensor positioned to sense a rotational motion of the shaft;
• a processor mounted on the housing and in electrical communication with the sensor;
• and
• at least one electrical contact in electrical communication with the processor and exposed on the exterior of the housing unobstructed to mate with at least one corresponding electrical contact when the replaceable unit is installed in the image forming device,
• wherein the processor is programmed to send information related to the rotational motion sensed by the sensor to a controller in the image forming device when the replaceable unit is installed in the image forming device.