Mars 5 Ultra

[JeffB]

Well Chris, to me that photo seems to sow that the sensor or sensors are strain gauges.  These are used on those inexpensive digital scales which can have resolution of fractions of gram.

Basically it's a semiconductor material which reacts to minute stretching/contracting changes to the material (metal) it is glued onto.  That hole which looks like 4 large holes drilled through provided thin enough cross section of metal for the strain gauge to be able to measure minute defection it.

Definitely <not> a "dumb" sensor!  Learn something new every day. 

Jeff