Patent ID: 8669514

Claim:
Apparatus for producing a seed count value in response to movement of seeds in a duct comprising: a light source arranged to be mounted at one side of the duct; a set of light sensors arranged to be mounted at an opposed side of the duct each for receiving light from the source; the set of light sensors being arranged such that passage of a seed through the duct between the source and the set of light sensors causes a shadow of the seed to fall on at least one of the light sensors; each light sensor being arranged to produce an output signal proportional to light intensity falling on the light sensor so as to generate a momentary change in the output signal therefrom proportional to the extent to which the shadow falls on the light sensor; and an electronic circuit into which the set of light sensors are connected; the light sensors and the electronic circuit being arranged so as to produce a resultant output signal where an amplitude of a momentary change in the resultant output signal in response to the passage of the seed is greater than an average change of the amplitudes in the output signals of all the light sensors of the set of light sensors.