Sub-50 µs Sample-Level Synchronization in a Battery-Powered BLE MEMS Accelerometer Node for Industrial Vibration Monitoring

Abstract

Accurate synchronization of data samples is crucial for wireless sensor networks (WSNs) used for vibration monitoring and condition diagnostics. This paper describes two practical methods for achieving sample-level synchronization with better than 50 microsecond accuracy on battery-powered wireless MEMS accelerometer nodes. The first method uses a hardware-based real-time synchronization approach, where each sensor node has a 1.024 MHz clock which is synchronized through periodic interrupt pulses. The second method employs a software-based cross-correlation alignment to achieve precise synchronization after data acquisition, which is suitable for cases without accurate hardware clocks. Both methods are implemented using compact Bluetooth Low Energy (BLE) sensor nodes with off-the-shelf components. Experimental results on a shaker test platform confirm that synchronization within 50 µs is reliably achieved with both methods, demonstrating the suitability of these methods for industrial vibration monitoring applications.