Cargonet: A Low-Cost Micropower Sensor Node Exploiting Quasi-Passive Wakeup For Adaptive Asychronous Monitoring Of Exceptional Events

This paper describes CargoNet, a system of low-cost, micropower active sensor tags that seeks to bridge the current gap between wireless sensor networks and radio-frequency identification (RFID). CargoNet was aimed at applications in environmental monitoring at the crate and case level for supply-chain management and asset security. Custom-designed circuits and sensors were utilized to minimize power consumption and cost in a practical prototype. The CargoNet nodes are capable of asynchronous multimodal wakeup on exceptional events at extremely low power (Quasi-Passive Wakeup) with adjustable thresholds that adapt to dynamic environments. Accordingly, CargoNet has been seen to monitor, log, and report conditions inside a typical shipping crate while consuming under 25 microwatts of average power. To demonstrate the feasibility of the prototype system, several tests and deployments were conducted in the laboratory and aboard various transport conveyances.