CMOS Smart Sensor for Monitoring the Quality of Perishables

Abstract

We developed a CMOS integrated-circuit sensor to monitor the change in quality of perishables that depends on sur- rounding temperatures. Our sensor makes use of the fact that the temperature dependence of the subthreshold current in MOSFETs is analogous to that of the degradation of perishables. The sensor is attached to perishable goods such as farm and marine prod- ucts and is distributed from producers to consumers along with the goods. During their distribution process, the sensor measures the surrounding temperatures and emulates the degradation of the goods caused by the temperature. By reading the output of the sensor, consumers can determine whether the goods are fresh or not. Our sensor consists of subthreshold CMOS circuits with a low-power consumption of 10 W or lower.