One-millisecond low-cost synchronization of wireless sensor network

Precise time synchronization is an important requirement for a wide set of distributed applications in which timestamped data should be produced by distributed nodes and then correlated with a limited amount of timing. There are several techniques and protocols that address this issue, however, most of them rely on specialized hardware and/or software solutions, thus incurring on relatively high cost to deploy a synchronization network In this paper, a low-cost approach to synchronize a wireless sensor network is proposed and applied in the context of an electrical power monitoring system, which is then used to build a dataset that supports research in the area of Non-Intrusive Load Monitoring (NILM). The monitoring system is designed to detect load events on several distributed nodes of a power circuit and to synchronize, with a millisecond precision, the voltage and current data collected on them. Results show that such a precision can be achieved with simple and relatively low-cost hardware, enabling this solution to be used on several contexts where the budget and time requirements are important concerns.