plate or tube and evaluate the oscillations that are produced by the impact of crop grains on the plate or tube this sensor technology can also be used and located at any other point in a combine harvester 1 this sensor technology allows flows of crop grains to be detected and makes it possible to obtain a determination u2014 that is comparative and relative at the least u2014 of the quantities of grain present at a particular site this sensor technology is also used in shakers 9 to detect the separation to obtain a determination of the amount of crop grains remaining in the straw a shaker loss sensor 19 is attached at least to the back end of a shaker 9 this sensor 19 detects the portion of crop grains separated at the end of shaker 9 to also evaluate the quantity of crop grains in the tailings a baffle plate sensor system of this type can also be located at the end of lower sieve 11 or at the point at which the tailings are returned to the threshing process to evaluate the crop components located in the tailings a tailings measuring device 16 is located on the upper end of tailing elevator 12 it is used to determine the tailings volume the portion of grain and the portion of damaged grain optical light barriers optical sensors or transillumination sensors nir sensors are known for use for this purpose grain elevator 13 is equipped with a yield measuring system 14 devices for measuring grain density can be located at different points on the combine harvester e g at the points indicated by dotted circles 36 37 in fig1 fig2 shows a schematic cross section through a grain density measuring device which can be located e g.