Figure 3.

3D model of the sensing structure: (a) axonometric view, (b) lateral view, (c) axonometric section and (d) lateral section. The basket used to collect the sand (A) has a flared shape in order to limit contacts with the inner walls of the rotating section that could alter the measured weight; the upper surface is shaped has a funnel. The load cell (B) is bolted to the closing cap of the amplifier housing and it is glued to an upper plate used to hold on the basket. The amplifier housing (C) contains the circuitry and it is closed in order to avoid sand infiltration inside.