Design And Implementation Of Low-power Wireless Data Acquisition Module

Cable transmission has certain requirements to environmental site and acquisition target, not suitable for complex terrain conditions, high corrosive, explosive, and other occasions, or acquisition target movement, rotation and so on. In these situations, wireless data acquisition showes the unique advantages, especially for those which are not suitable or convenient to set up the cable at the scene. Wireless data acquisition usually uses the multi-byte code addresses, so the number of transceiver is no restriction, with a simple circuit, small consumption, small size and low cost.On the basis of the comprehensive analysis of Bluetooth, IrDA, GSM \ CDMA \ GPRS, IEEE802.11x such as wireless data collection methods, this paper determine to use radio frequency transceiver integrated chip solutions basing on the low-power short-range radio frequency wireless communications technology. Design and implement wireless data acquisition module by a Nordic company's product nRF905 and 8-bit AVR microcontroller Series's Mega8. The main of thesis and study includes the following:1. Make module overall planning, design the structure of a acquisition node and receive node. By the actual needs, and performance, price and other factors to consider, select the components of the module, the AVR family of high-end microprocessors 8-bit MCU Mega8, radio-frequency chips Nordic company's product nRF905. Completed the hardware design, acquisition node is the primary function of collecting data from Mega8 processed and transmitted through the nRF905, the function of receiving node is receiving data from nRF905 and processing data by Mega8, and the data can be transfers through the RS232 to PC. In addition, maked ISP download cable, the ISP cable is use to programming procedures, with a multi-purpose, the use of flexible, convenient on-line features of the upgrade.2. From the MAC layer function, according to the practical application, the structure of the wireless communications module, wireless media access, the establishment of communication links, resumption of error, sending and receiving simultaneously, the data frame format the were analyzed to establish a communication module model and design the small wireless network program by the smart nodes, using star topology network and CSMA / CA (Carrier Sense Multiple Access Point / avoid the conflict)network protocol. Completed the application software development and debugging. The main modules including the driver program, wireless transceiving and sending program, RS232 interface program, as well as smart nodes small wireless network program.3. The module was tested, and the test results show that the design of wireless data acquisition module is a small, stable and reliable data transmission, the use of of flexible module and can well be applied to short-range wireless data acquisition and other short-range wireless data transmission occasions.