Capturing and recording cold chain temperature violations through parametric alarm-sensor tags

Abstract

While the Internet-of-Things has already fueled a plethora of different possibilities, we are still in need of means to mitigate the inefficiencies of the cold chain generating every year massive food and drug waste, even causing serious illnesses. This is caused by the lack of remote sensing technologies suitable for a widespread deployment able to timely mark any cooled items exposed to inadequate temperatures. This work introduces a class of printable, battery-less, and chip-less passive tags, namely, the Parametric Alarm Sensor Tags (PASTs), allowing detection of any violations in the storage temperature of refrigerated items with extraordinary reading ranges. In order to do so, PASTs leverage a three-way sensing scheme and nonlinear dynamics never explored in any tag technologies to trigger the passive generation of a radio frequency signal only when the temperature exceeds a remotely configurable threshold (Tth). Furthermore, PASTs exhibit a dynamically enabled temperature-controlled hysteresis loop. As a result, the signal generated at the occurrence of a temperature violation remains active even if the temperature returns within a tolerable range. This allows us to flag any items previously or currently exposed to inadequate temperatures, allowing their prompt identification. We report a 870 MHz PAST and show that, thanks to its unique characteristics, it is finally possible to identify any items along the cold chain whose temperature has exceeded a remotely configurable Tth value as low as −47 °C, even if operating in uncontrolled electromagnetic environments and up to 46 m away from the corresponding PAST outside a line-of-sight.