Abstract: A system for layup of a solar cell string on a substrate includes a robotic arm having a pickbar attached to a free end thereof. The pickbar has an elongated body with a plurality of vacuum grippers spaced along the body each for gripping an individual solar cell of the solar cell string. A vacuum source applies a vacuum through the vacuum grippers to grip the solar cells and a controller connected to the robotic arm positioned the solar cell string gripped by the pickbar on a substrate. A pair of sensor assemblies mounted on the pickbar generates signals representing positions of portions of the solar cell string and features of the substrate. The controller responds to the signals for positioning the gripped solar cell string relative to the substrate.