System and method for identification of contact between an object and a static implement in a power tool

A power tool comprising:

• an actuator configured to move an implement;
• a clock source configured to generate a time varying electrical signal that passes through the implement;
• and
• a controller operatively connected to the actuator and configured to sample the electrical signal, the controller being configured to:
• generate a sample of the electrical signal when the actuator is deactivated and the implement is a non-moving implement;
• identify an in-phase component and quadrature phase component of the sample;
• identify a first distance as a first Pythagorean distance in a two-dimensional plane corresponding to the in-phase and quadrature-phase signals, the first distance being between the identified in-phase component and quadrature phase component of the sample at a first location in the two-dimensional plane and another in-phase component and quadrature phase component of a first centroid at a second location in the two-dimensional plane, the first centroid being of a first cluster of samples corresponding to human contact with the non-moving implement;
• identify a second distance as a second Pythagorean distance in the two-dimensional plane, the second distance being between the first location of the sample and another in-phase component and quadrature phase component of a second centroid at a third location in the two-dimensional plane, the second centroid being of a second cluster of samples corresponding to no human contact with the non-moving implement;
• and
• identify human contact with the non-moving implement with reference to the first distance being less than the second distance.