Level, plumb, and perpendicularity indicator for power tool

A power tool comprising:

• a housing;
• an output shaft extending from the housing in a direction of a tool axis;
• a motion sensor including at least one accelerometer configured to sense motion of the tool housing by detecting acceleration of the tool housing along an X-axis that is substantially parallel to the tool axis, a Y-axis that is substantially orthogonal to the X-axis, and a Z-axis that is substantially orthogonal to the X-axis and the Y-axis, the motion sensor further configured to generate at least one input signal that comprises an X input value corresponding to acceleration of the tool housing along the X-axis, a Y input value corresponding to acceleration of the tool housing along the Y-axis, and a Z input value corresponding to acceleration of the tool housing along the Z-axis;
• a control circuit configured (a) to receive the at least one input signal from the motion sensor, (b) to make a first determination, based on the at least one input signal, automatically, whether the tool is being operated in a horizontal mode or a vertical mode wherein in the vertical mode the tool axis is substantially perpendicular to ground and in the horizontal mode the tool axis substantially parallel to ground, and (c) to make a second determination, based on the input signal, whether the tool axis is substantially level when the tool is being operated in the horizontal mode or the tool axis is substantially plumb when the tool is being operated in the vertical mode, wherein the control circuit is configured to make the first determination by comparing one of the input values or a result of a calculation of two of the input values to an at least one reference value that has been pre-stored independently of a user input, in order to distinguish whether the tool is being operated in the horizontal mode or the vertical mode, and
• an indicator coupled to the control circuit, the indicator configured to receive an output signal from the control circuit that causes the indicator to indicate whether the tool axis is level when being operated in the horizontal mode or plumb when being operated in the vertical mode.