The sensor above is the a strain gauge load cell[34]. The load cell itself is mounted to a metal beam with large holes in it so it can deflect when a load is placed on to it. The strain gauge itself changes its resistance when a load is applied but the output voltage is so low that an amplifier is needed.
The figure above shows the HX711 load cell amplifier which takes the signal from the load cell and amplifies it and converts it to a nice clean digital signal similar to I2C but not quite. In this chapter we’re going to wire up the load cell and then read the data from amplifier after calibrating it properly.
