A surgical instrument is disclosed. The instrument includes a handle portion, a body portion extending distally from the handle portion and defining a first longitudinal axis and an articulating tool assembly defining a second longitudinal axis and having a proximal end. The articulating tool assembly is disposed at a distal end of the body portion and is movable from a first position in which the second longitudinal axis is substantially aligned with the first longitudinal axis to at least a second position in which the second longitudinal axis is disposed at an angle with respect to the first longitudinal axis. The instrument also includes an articulation mechanism configured to articulate the articulating tool assembly, the articulation mechanism including an articulation sensor assembly configured to transmit a sensor signal to a microcontroller which is configured to determine an articulation angle of the articulation assembly.