The Design Of A Low-power Mine-used Wireless Oil Pressure Sensor Circuit System

Mine pressure is an important parameter about mine safety, it has closely relationship with gas, water inrush and roof fall accidents. At present, most of the mine pressure monitoring system using in coal mines are wired, it can provide a stable and reliable communication, but it has some shortcomings. It is hard to place and route lines in harsh environment, which can cause a blind spot monitor. The monitoring device must move when mechanized mining face tunneling process. It is inconvenience to move a large number of cables with the mobile device, which will reduce the efficiency of mining. And the falling rocks easily cut the cable, causing the monitoring system can not monitor the relevant areas. In order to solve the problems of cable monitoring systems, wireless sensor network technology has been widely used in mine safety monitoring system.This paper is based on wireless sensor network technology, we analysis the functional requirements of mine operation device, and design a wireless and low-power pressure sensor network node, which can adapt mine environment and meet the application requirements. Based on low power consumption, we optimize design of hardware circuit of the sensor node, software process and the system clock. We choose MSP430 as the control center, then design pressure signal acquisition, clocks, buttons, LCD display, EEPROM, Flash module and wireless module associated circuits, each circuit module is equipped with digital switches, providing the method about sleep function in the circuit. Software system uses interrupt scheduling method, which can effectively increase the sleep time of core circuitry and save energy consumption. When the system is running, CPU power consumption accounts for a large proportion of system power consumption, the time of processing and operating clock frequency is two main factor about CPU power consumption, MSP430 has a rich and flexible clock system. Without affecting the system performance, it can effectively reduce CPU power consumption through the rational deployment of the system clock source.Oil pressure sensor is made of silicon diffusion, and it’s range is 0 ~ 70 Mpa. In the laboratory environment, diffused silicon sensor input and output characteristics are measured, according to the measured data fit the curve between input and output of the sensor, this paper presents the fitted curve uncertainty formal expression. Finally, we test digital underground pressure sensor, test results show that the maximum load of digital sensor error does not exceed 0.1Mpa, it can meet the design requirements.