Resumen
Sensor for measuring the firmness of fruit by impact.The invention consists of a sensor capable of making non-destructive measurements of the firmness of whole fruits in a classification line. The sensor is based on the response to the impact of a small hemispherical mass fixed to the end of a horizontal pivoting arm. The response of the fruit to the impact is measured by a miniature accelerometer mounted behind the impact head. The response to the impact consists of an acceleration-time signal during the time of contact between the impact head and the fruit. From analysis of this signal, a firmness index can be calculated. The impact arm is initially held by an electromagnet and is released by a spring when the electromagnet is switched off. The sensor, actuators and frame occupy a small space and the device can measure the firmness of at least 8 fruits per second and is thus suitable for use in a classification line.