A sensor system for detecting and processing EMG signals comprising: a substrate (16, 35) having a bottom surface (19, 40) adapted for attachment to skin; a plurality of spaced apart electrodes (A1 - D1; A4 - E4) projecting from said bottom surface so as to engage the skin and detect EMG signals in a muscle located under said substrate, said electrodes (A1 - D1; A4 - E4) being arranged to provide four distinct pairs (A1,B1; B1,C1; C1,D1; D1,A1 or A4,E4; B4,E4; C4,E4; D4,E4) of said electrodes, wherein said distinct pairs of said electrodes (A1 - D1; A4 - E4) are spaced apart in different directions on said substrate; an amplifier section (13,30), a filtering section (14,33) and a decomposing section (15,34) connected to said electrodes (A1 - D1; A4 - E4), the amplifier section (13,30) comprising four differential amplifiers (21 - 24, 37,38,39,41;) each connected to receive EMG signals from one of the distinct pairs of said electrodes (A1 - D1; A4 - E4); the decomposing section (15,34) comprising decomposition circuitry connected to receive the four channel signal output from the differential amplifiers (21 - 24, 37,38,39,41), wherein each of the distinct pairs (A1,B1; B1,C1; C1,D1; D1,A1 or A4,E4; B4,E4; C4,E4; D4,E4) of said electrodes (A1 - D1; A4 - E4) is configured to detect the action potentials of the muscle fibers from a different orientation so that the shape of an action potential appears substantially dissimilar in each of the four distinct pairs; and wherein the decomposition circuitry (15,34) is configured to decompose the compound electrical signal detected from the electrodes' output signals into individual action potentials. a substrate (16, 35) having a bottom surface (19, 40) adapted for attachment to skin; a plurality of spaced apart electrodes (A1 - D1; A4 - E4) projecting from said bottom surface so as to engage the skin and detect EMG signals in a muscle located under said substrate, said electrodes (A1 - D1; A4 - E4) being arranged to provide four distinct pairs (A1,B1; B1,C1; C1,D1; D1,A1 or A4,E4; B4,E4; C4,E4; D4,E4) of said electrodes, wherein said distinct pairs of said electrodes (A1 - D1; A4 - E4) are spaced apart in different directions on said substrate; an amplifier section (13,30), a filtering section (14,33) and a decomposing section (15,34) connected to said electrodes (A1 - D1; A4 - E4), the amplifier section (13,30) comprising four differential amplifiers (21 - 24, 37,38,39,41;) each connected to receive EMG signals from one of the distinct pairs of said electrodes (A1 - D1; A4 - E4); the decomposing section (15,34) comprising decomposition circuitry connected to receive the four channel signal output from the differential amplifiers (21 - 24, 37,38,39,41), wherein each of the distinct pairs (A1,B1; B1,C1; C1,D1; D1,A1 or A4,E4; B4,E4; C4,E4; D4,E4) of said electrodes (A1 - D1; A4 - E4) is configured to detect the action potentials of the muscle fibers from a different orientation so that the shape of an action potential appears substantially dissimilar in each of the four distinct pairs; and wherein the decomposition circuitry (15,34) is configured to decompose the compound electrical signal detected from the electrodes' output signals into individual action potentials.