Device and method for detecting maturity and size of winter jujubes

The invention relates to a device for detecting the maturity and size of winter jujubes. The device comprises a base plate, an electromagnet, two clamping fingers and two finger base plates, wherein the clamping fingers and the finger base plates are connected through four guiding posts and springs arranged on the guiding posts in a sleeved manner; the electromagnet and a connecting shaft for connecting the two finger base plates are fixedly arranged on the base plate; the rear ends of the two finger base plates are connected with connecting rods; the connecting rods and an output rod of the electromagnet are connected through a rotating shaft; the rear end of one clamping finger is provided with a potentiometer; a sliding block at the bottom of a rotating shaft of the potentiometer is arranged inside a slideway along the base plate; a mounting groove is further formed in the inner side of each clamping finger; each mounting groove is internally provided with a detection device. A method for detecting the maturity and size of winter jujubes comprises the following steps: (1) the electromagnet works, and the clamping fingers clamp a winter jujube; (2) the change of resistance is detected through the potentiometer to determine the size of the winter jujube; (3) the maturity of the red jujube is judged by a photoelectric cell; (4) the steps are repeated in a circulating manner to realize selection of winter jujubes.