A sensor cell (1010) for control purposes usable in an assembly (1000) of fuel cells of the type having a membrane electrode assembly (MEA) interposed between an anode gas diffusion layer and a cathode gas diffusion layer, and first and second current collectors coupled to the anode and cathode gas diffusion layers (GDL), respectively. The sensor cell (1010) is preferably coupled so that it shares the negative current collector (1050) with last fuel cell in the in-plane fuel cell assembly (1000), and is short-circuited by a resistor (1070) to provide a voltage signal, indicative of the status of the assembly in operation.