Research Of Wireless Sensor Network Based On Bluetooth Low Energy

Wireless Sensor Network(WSN) is the integration of sensing, communication and computing. It is a brand-new technology for information acquisition and processing. Most of existing researches are based on ZigBee, ANT, 6LoWPAN or non-standard RF protocols. However, the good anti-interference and low power consumption characteristics of the emerging Bluetooth Low Energy(BLE) technology make it more suitable for use in wireless sensor networks. With the popularity of Bluetooth 4.0 on smartphones and tablets, the wireless sensor network based on BLE can interact directly with them which make it more flexible in application. And this is what ZigBee and other protocols cannot achieve.This article presents the comparison between common wireless technologies used in wireless sensor network and the emerging BLE technology, and introduces the research status of wireless sensor network based on BLE. In consideration of the features of BLE, it has designed the overall scheme, and the topology structure of wireless sensor network based on BLE is proposed.The board-level network node hardware based on CSR1010 BLE IC is designed and implemented. The node contains a rechargeable lithium battery and can be charged through a Micro USB connector. Moreover, it can provide 3.3V and 5V power to external sensors directly. The software for network node is designed. With CSR ?Energy SDK and CSR Mesh 1.1 Library, the CSR Mesh network communication ability and node configuration read-write ability are implemented. A library including dynamic memory management and other C standard library functions that lack in the SDK is implemented. A tiny Tcl scripting language interpreter- Picol is ported and optimized. It presents the implementation of Tcl commands for PIO ports, AIO ports, I2 C interface, SPI interface and UART interface operating. A flexible data reading for different types of sensor is achieved.A PC-side configuration tool for node is designed and the related code has been written, which implemented wireless reading and writing to the configuration information including device name, device address, RF transmitting power, script execution interval and Tcl script code. An Android application that control the whole network is designed and the related code has been written, which implemented device management for each node in network and sensor data view.At last, a functional test for the completed network node is performed using actual sensors, and the working current under different transmitting power and sleeping current are measured.As a tentative exploration for applying BLE to wireless sensor network, this article has certain reference value to similar designs and developing practice. It is believed that with the maturity of BLE, related research will be further improved.