Design and Realization of a Wireless Data Acquisition System Based on Multi-Nodes and Multi-Base-Stations

Multi-nodes inertial data acquisition has the widespread applications in medical rehabilitation research and biomechanical analysis. In the traditional method, the inertial data of every child-node is sent to a center node by wired line firstly. Then the center node transfers the data of all child-nodes to PC through a single serial port. This approach has some obvious drawbacks, including the fact that the sampling rate is low, the communication protocols are complex and installation is inconvenient. This article proposed a multi-node and multi-base-station wireless data acquisition system. The communication between child-node and the base-station is performed in a point-to-point manner. The data of micro inertial sensors on the child-node circuit board is collected by the MCU then is sent to the matching base-station by the RF module. The base-station send data packet to the upper computer through serial port. The results showed that the upper computer software can collect data packets synchronously from three child-nodes (the data packet of each child-node contain 19 Bytes) with high-speed sampling rates up to 118 Hz. And there is no obvious deferring time under this condition. The technique has the certain applications in the data collecting system of motion capture. Key words: Pcomm; multi-thread; multiple serial ports; nRF905; MPU6000