System and method for sensing the angular position of a rotatable member

A method for sensing the angular position of a rotatable member, the method comprising the steps of:

• providing a composite rotatable member comprising a solidifiable material and a magnetically attractable particulate material dispersed throughout the solidifiable material, the rotatable member having a major body portion and at least one magnetically detectable reference point in the major body portion defined by a concentrated portion of the magnetically attractable particulate material, the reference point having a first magnetic property and the major body portion having a second magnetic property, different from the first magnetic property, the reference point containing a first volume percent of the magnetically attractable particulate material and the major body portion containing a second volume percent of the magnetically attractable particulate material, the first volume percent being greater than the second volume percent, the first volume percent being at least about 1.5 times to 10 times greater than the second volume percent;
• providing a magnetic property sensor which is fixed relative to the rotatable member;
• detecting the passage of the reference point within the rotatable member and producing a signal in response to the passage of the reference point;
• and
• providing a processor and determining the angular position at the rotatable member in response to the signal from the sensor.