Wireless low-power temperature probes for food/pharmaceutical process monitoring

This work presents the design, fabrication, and characterization of a wireless, low-power, multi-point temperature sensor system for process monitoring applications. This is particularly useful for low-temperature applications commonly found in pharmaceutical and food processing plants where accurate monitoring of temperature over long time intervals (e.g. days) is necessary. Using capacitive temperature elements, a wireless three-point temperature measurement in liquid has been successfully demonstrated. The system has been tested down to 55°C and achieves a resolution of <;0.01°C. The developed system utilizes the low power ANT wireless protocols for data transmission. This allows operation in the 2.4 GHz ISM band and supports large-scale sensor network topologies (2³² nodes). The entire system occupies a small footprint of 13 by 33 mm² with a power consumption less than 1 mW.