The invention provides an apparatus and methods for applying a material to a cable or into a conduit. To determine the input coordinates, a predetermined number of pairs of light emitting elements and light detecting elements are placed in parallel for each axis near the edges. In addition, the provided light emitting semiconductor device fabricated via a planar technology process is microscopically planar, but not planar at micro- and nano-scale. The sheath includes a fixing element configured to fix the electrode in place along the tissue.