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Machinery fault diagnosis plays a very important role in the modern production. And it is the main method to extract information and parameters, which represent vibration status, from vibration signals, so research and development on low-frequency vibration signals acquisition system is of great significance. The embedded technology which impels the development of electronic products toward more economy, smallness, reliability, efficiency and intelligence has become a research hotspot and provided wide development space for the modern signals acquisition system. In this paper, based on the ATmega64L microcontroller, a new type of hand-held 4-channel low-frequency vibration signals acquisition system used for machinery fault diagnosis is researched and developed, which synthesizes data acquisition the-ory,embedded technology and design techniques of Low-power.Firstly, the paper summarizes the background, significance, present developing condition, theory and technology of vibration signals acquisition system design, Secondly, based on the high-speed and high performance-to-price ratio ATmega64L microcontroller, we carry out detailed design, which includes hardware and software of the system. The hardware design based on the’modular design’ concept has been completed. It is made up of sensor signal conditioning, signal acquisition, A/D conversion, FM24C256 storage, serial communication, SD card interface, keyboard controlling, liquid crystal displaying, power supplying and other circuits; In the software design, based on the designing principles of’from top to end’, each aspect is considered comprehensively, then acquisition programs, FFT analyzing algorithm programs, keyboard controlling programs, displaying programs and data communicating pro-grams are designed and their algorithms flow charts are given. Meanwhile, the vibration sig-nals analysis software is designed using LabVIEW to display and analyze the vibration sig-nals. Finally, the integrated debugging including hardware and software are finished to verify the reservation functions of the low-frequency vibration signals acquisition system. Through-out the design process, three core technologies are emphasized, they are:FFT algorithm of 128-point sampling data, data transmission from FM24C256 to SD card and the design of Low power consumption and anti-jamming technology.In order to verify accuracy and reliability of low-frequency vibration signals acquisition system, several purposive experiments have been finished. The experimental results show that, the data acquisition is timely, the FM24C256 storage is safety, the data transmission is reliable, the FFT result is accurate and the Human-Computer Interface is convenient. In a word, all the modules of the hand-held low-frequency vibration signals acquisition system work well, and fully meet the functional requirements of the design targets.The hand-held low-frequency vibration signals acquisition system has the characters of smallness, organic integration of software and hardware, low-power, reliability, intelligence, high performance-to-price ratio and easily handled by giving full play to the advantage of embedded technology. So the system is suitable for large-scale promotion, and has broad market prospects.
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