Various embodiments of a bioelectric sensor device for sensing bioelectric data from a human body are disclosed. The device can include a flexible substrate, a plurality of sensors arranged in a sensor array on a sensor array portion of the substrate, an electrically conductive network located on the substrate, and a plurality of lines of weakness formed in the sensor array portion of the substrate. In one or more embodiments, each line of weakness is configured to enhance separation of the sensor array portion of the substrate along a separation line that extends between at least two sensors of the plurality of sensors. The device can also include a left reference electrode proximate a distal end of a left reference electrode arm of the substrate and a right reference electrode proximate a distal end of a right reference electrode arm of the substrate.