This paper pretends to demonstrate the design, construction and test of an opto-electronic system measures external loads apply to a mechanical element (load cell)<sup>1</sup>. This device works under the action of external loads and voltage differential to convert a digital signal. This function principle is related with the variation of the angle of incidence of the light signal on an electronic element sensible to light. A difference between this method and other conventional methods it is precisely that the sensible element is not exposed directly to work loads. This prototype represents an alternative method to industrial applications.