Automatic calibration technologies were useful at reducing the impacts of methane sensorpsilas stability that led to shortcomings of traditional gas detector, such as frequent recalibration, high maintenance cost, and high false alarm rate. This paper described a mini intelligent methane sensor to be used as a sensing node to form a real-time methane monitoring network based on nRF240. Moreover, a novel auto-calibration method is proposed to achieve the maintenance-free operation using the sensor network and achieved the auto diagnosis, and automatic dynamic correction of sensor nonlinear characteristic. This paper introduced the principle of the method, the hardware and software of the composing module. The network connectivity can be used not only for methane data collection but also for the calibration and diagnosis of the sensors through data processing of the nearby sensing node, which provided the effective supporting for automatic calibration of the single intelligent methane detector. An intelligent methane sensor system equipped with the network connectivity can perform the calibration autonomously in the field, and there is no need to prepare standard gases for each system as in the conventional calibration.
[Show abstract][Hide abstract] ABSTRACT: This paper describes the development of a mini intelligent methane sensor system to be used as a sensing node to assure a safe work environment in underground coal mines. Machine-mounted methane monitors must be used to continuously monitor methane levels during mining. The weak output signal from the Wheatstone bridge circiut often corrupts by sensor offset, noise, temperature and aging drift. This paper analyzed the main techniques of the developing Intelligent methanometer, such as automatic calibration, offset cancellation, sensitivity correction of the methane sensor's nonlinear and the influence of O-2 concentrations, and evaluated the performance of the methane measuring system. The experimental results and industry testing has shown that the capability of our system met with the requirement of standard for safety produce in coal mine. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011]
"Node uses 8-bit 8 MHz microprocessor and 38.4 Kbps data rate operating at 433 MHz radio. Zhang et al. (2008) developed software for monitoring methane gas concentration and hardware node by using a mini intelligent methane sensor to form a real-time methane monitoring network based on NRF240. Network can be used both for data gathering and calibration purposes . "
[Show abstract][Hide abstract] ABSTRACT: Wireless sensor prototypes have varying hardware architectures and distinctive sensing principles. In this study, a prototype is developed for the purpose of monitoring leaks of methane (CH 4), which has explosive properties and is the main constituent of the natural gas, in the refineries or buildings and work places heating. The prototype can be mounted on the walls as well as it is portable. System is composed of the integration of methane gas sensor module NGM2611 to MicaZ mote. The sensor module is pre-calibrated and is a product of FIGARO firm. The MICAz is a 2.4 GHz, IEEE/ZigBee 802.15.4; board used for low-power, wireless and sensor networks. By means of the designed sensor prototypes, wireless sensor networks are established indoors; hence, methane gas leaks are detected and sent to the base stations. Data received by base station is monitored by the software on a computer connected to the base station. This study explains the system structure, parts of hardware and software design in detail. The aim of the system is to implement a wireless methane gas platform. This platform can be used to real time monitoring of the methane leaks which would be crucial for critical conditions and helpful to decrease risk of death due to those leaks.
Scientific research and essays 01/2010; 5(8). · 0.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Effective communication is critical to the success of response and rescue operations; however, unreliable operation of communication systems in high-stress environments is a significant obstacle to achieving this. The contribution of this article is threefold. First, it outlines those common characteristics that impair communication in high-stress environments and then evaluates their importance, specifically in the underground mine environment. Second, it discusses current underground mine communication techniques and identifies their potential problems. Third, it explores the design of wireless sensor network based communication and location sensing systems that could potentially address current challenges. Finally, preliminary results are presented of an empirical study of communication using a WSN constructed from commercially available wireless sensor nodes in an underground mine near Parkes, New South Wales, Australia.
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