Bluetooth-based Wireless System For Vibration Monitoring

Vibration analysis has been widely applied in the field of engineering and healthcare, such as machinery operation diagnosis, earthquake prediction, structural health monitoring of buildings, respiration rate, pulse wave, intensity of training, etc. Traditionally vibration signals are transmitted via cables which face operation difficulties in various situations, such as a rotating project, a deep mining tunnel full of flammable gases, etc. Then employment of the wireless transmission system(s) comes to be the alternate.Herein we’ve compared several popular techniques of wireless communication. For an vibration detection, both the frequency and the magnitude are to be time-resolved. Hence, to meet the requirements of measurement and achieve advantages of low cost, low power, and high transmission rate, Bluetooth technique was chosen for the final experimental scheme. A wireless vibration monitoring system has been realized basing on Bluetooth technique:(1) HardwareA piezoelectric accelerometer has been employed taking advantage of its high stability and nice temperature adaptability; A charge integrating amplifier was used to amplify the sensor output and the signals were filtered; A microcontroller with eight-digit precision converts/manipulates the transmitted signals; Digitized signals were emitted via a Bluetooth module; Finally, the main Bluetooth module at the receiving side input signals to a PC via a USB interface circuit.(2) SoftwareFirst, use the C language to design a signal acquisition and transmission program; Then, develop an user interface(UI) in the LabVIEW environment, involving functions of control of the microcontroller, real-time display and storage of accepted data, and Fourier transforming analysis for the data.Finally after a debugging process, the wireless vibration monitoring system was established. The final system was evaluated with input of ideal 10 hz, 50 hz, 100 hz sinusoidal vibration sources. Testing results showed a frequency detection error lower than 5% and proved itself the practical utility. The experimental results also further support the wide application of Bluetooth technique in the field of wireless sensing. In other words, Bluetooth technique can be a trusted technique for wireless sensing.