MINE SAFETY MONITORING SYSTEM WITH ZIGBEE AbstractIn this work, a safe Coal Mine Monitoring system which replaces the traditional coal mine monitoring systems which tend to be wired network systems. This play an important role in coal mine safe production. With continuous enlarging of exploiting areas and extension of depth in coal mine, many laneways become monitoring blind areas, where are lots of hidden dangers. Moreover, it is inconvenient to lay cables which are expensive and co nsume time. In order to solve the problems, we designed a coal mine safety monitoring system based on wireless sensor network, which can improve the level of monitoring production safety and reduce accident in the coal mine. Zigbee technology provides a direction for scientists who commit to solve the safety monitoring problems of coal mine. The purpose of this study is to propose a solution suitable to mine wireless communication, safety monitoring, give a proof to the further study.

INTRODUCTION

The safe production level of coal mine is still low, especially in recent years, disasters of coal mine occur frequently, which lead to great loss of possession and life, the safety problems of coal mine has gradually become to the focus that the nation and society concern on.

The disasters of coal mine happening are due to the complexity of mine environment and the variety of work condition of coal mine, so it is very necessary to monitor mine working environment. The various environmental parameters of mine safety monitoring and controlling system, such as methane, carbon monoxide, temperature, oxygen and so on, are currently using the traditional cable transmission. Thus truly mine methane, carbon monoxide gas accumulation area mechanized mining face, such as the dead gob cable security parameters cannot be monitored, so they cannot predict the alarm. A variety of products for the current diversity of coal mine safety and underground coal mining process variability space, mine safety wireless network should be compatible with existing mine safety system with data transmission functions, has good flexibility, scalability, self- set of network capabilities. As the mine has its own special applications require a simple sensor network protocols, network easy, self-organization, selfhealing ability. Zigbee is a wireless communications technology, with a short distance, safe and reliable, you can use Zigbee technology to collect the various parameters of the terminal transmitted to the sensor on the tunnel gateway, and then use a wired data transmission to the gateway on the ground central control computer, by computer analysis and comparison of the data in order to assess the security situation in the Mine. To achieve the target location underground, environmental and other parameters of the remote collection, can provide scientific basis for relief. Underground mine environment, the complexity of the power consumption, interference immunity and so have more stringent requirements.

In [8], an agent-based wireless local positioning system with ZigBee technology is proposed, mainly for factory level applications. A cost effective ZigBee-based wireless mine supervising system with early-warning intelligence on methane, temperature, humidity in mining area is proposed in [9]. Again, another article [10] presents the development of a system integrated to a ZigBee network to measure the whole human body vibration, for the persons exposed to vibratory environment. ZigBee specification is incorporated by many manufacturers in their devices because of its low power consumption and decreasing development cost. In the work presented here, Digi make ZIGBEE24 product is used here for transmitting and receiving data wirelessly.ARCHITECTURE OF THE SYSTEMThe developed system can be divided into two sections. First is a hardware circuit that will be

attached with the body of the mine workers. This may be preferably fitted with the safety helmet of the workers also.

The circuit has a sensor module consisting of some MEMS based sensors that measures real-time

underground parameters like temperature, humidity and gas concentration.

Gas concentration is meant for the harmful gases like methane and carbon-monoxide. A microcontroller is used with the sensors to receive the sensor outputs and to take the necessary decision. Once temperature is more than the safety level preprogrammed at microcontroller, it decodes beep alarms through the headset speaker connected with controller as shown in Fig. 1. Again, once the measured humidity value is more than the safety level preprogrammed at microcontroller, it decodes different type of beep alarms.Similarly when gas concentration crosses the safety level, microcontroller decodes siren alarms. In all such cases, this will send an alarm through an urgent message and alarm sound to the ground control terminal through zigbee.

The microcontroller data is transmitted through two separate boards i.e. ZigBee transmission module to the data collector or receiver module. The microcontroller used here is PIC TMEGA16 with 16MHz operating frequency. It has five I/O ports,eight A/D input channels and 368 bytes data memory. As shown in Fig. 2, the data receiving terminal of Zigbee XB_RX and data transmitting terminal XB_TX are cross connected to the microcontroller corresponding transmitter and receiver terminals TxD and RxD respectively. No extra component like MAX 232 and MAX233 is required between theseconnections.

This is the advantage of ATMEGA16 .If the structure of UART (Universal Asynchronous

Receiver Transmitter) system is completed, sending and receiving signal is possible using ZigBee, after installing necessary software. The RESET pin of Zigbee is used to provide an optional reset facility of user through a reset button. A transistor is used for this purpose.

The Zigbee Modules used in the interfacing boards, are engineered to meet IEEE 802.15.4 standards. It is low-cost, low-power, reliable 20 pin device that operates within the ISM 2.4 GHz frequency band. It has 30 to 100 metre data transmission capability with rate of 250,000 bps. Zigbee modules operate in five modes. When not receiving or transmitting data, the RF module is in Idle Mode. The RF module shifts into the other modes of operation under various conditions.

BLOCK DIAGRAM

Working ZigBee wireless sensor nodes mainly consist the sensor unit, signal conditioning circuitry, microcontroller (MCU), power management module and other components.

Micro-controller is responsible for collecting environmental information (such as temperature, methane, Humidity) and do some data conversion.

Responsible for controlling and managing the entire nodes.

The power module provides the necessary power for the nodes separately to run the various parts. Data from Microcontroller is fed to zigbee to transmit data wirelessly.

Transmitted data is received by ground station, for monitoring storage and processing.

According to environmental condition of coal mine emergency alarm signal is generated and send to the coal mine station.

When emergency signal is received by the coal mine siren is blow to alert the mine workers.

HARDWARE IMPLEMENTATIONZigBee wireless sensor nodes mainly consist the sensor unit, signal conditioning circuitry, microcontroller (MCU), Micro-controller is responsible for collecting environmental information (such as temperature, methane, Humidity, etc.) and do some data conversion, responsible for controlling and managing the entire nodes; Zigbee Module is responsible for the communication between nodes by a certain protocol ; the power module provides the necessary power for the nodes separately to run the various parts.

Sensor nodes are the basis unit of wireless sensor network; node stable running ensures the reliability of the whole network. Sensor node is comprised of data acquisition module, data processing module, wireless communication module, alarm module and the power module.HARDWARE AND SOFTWAREHardware

Zigbee XBee/XBee-PRO ZB RF Modules The XBee Module 2mW PCB Antenna - Series 2 (ZigBee Mesh) allows a very reliable and simple communication between microcontrollers, computers, systems, really anything with a serial port. Point to point and multi-point networks are supported. These are essentially the same hardware as the older Series 2.5, but have updated firmware. They will work with Series 2.5 modules if you update the firmware through X-CTU. The modules require minimal power and provide reliable delivery of data between remote devices.ZigBee is a specification for a suite of high level communication protocols used to create personal area networks built from small, low-power digital radios. ZigBee is based on an IEEE 802.15 standard. Though low-powered, ZigBee devices often transmit data over longer distances by passing data through intermediate devices to reach more distant ones, creating a mesh network; i.e., a network with no centralized control or high-power transmitter/receiver able to reach all of the networked devices. The decentralized nature of such wireless ad hoc networks make them suitable for applications where a central node can't be relied upon.

ZigBee is used in applications that require a low data rate, long battery life, and secure networking. ZigBee has a defined rate of 250 kbit/s, best suited for periodic or intermittent data or a single signal transmission from a sensor or input device. Applications include wireless light switches, electrical meters with in-home-displays, traffic management systems, and other consumer and industrial equipment that requires short-range wireless transfer of data at relatively low rates. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth or Wi-Fi.

Features 250kbps Max data rate 2mW output (+3dBm) 400ft (120m) range Fully FCC certified 6 10-bit ADC input pins 128-bit encryption Local or over-air configurationMICROCONTROLLERATMEGA16

AT - It stands for the company that produced the microcontroller, ATMEL.Mega - Stands for the family of Microcontroller. The other families from Atmel are Tiny & X-Mega.

16 - Stands for the 16KB flashmemory that is present in the microcontroller.

The AVR is a modified Harvard architecture 8-bit RISC single chip microcontroller which was developed by Atmel in 1996. The AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time.

CMOS RISC, AVR ATmega16, 8-BIT Microcontroller, In-system Programmable with Flash code storage, re-programmble up to 1000 times. Features 32 working registers, single clock cycle execution giving up to 1MIPs/MHz.

ATmega16 Features 16K BYTES of In-System Programmable Flash

512 BYTES of In-System Programmable EEPROM

1K Bytes SRAM

Analog Comparator

Watchdog

SPI

2 8-bit Timers plus prescaler

16-bit Timer with extra features

4 PWM

8 channel 10-bit ADC

UART

SPI

2-wire byte orientated serial interface

Low power and Idle modes, External and External interrupts, selectable on-chip Oscillator

GAS SENSOR

This is a simple-to-use compressed natural gas (CNG) sensor, suitable for sensing natural gas (composed of mostly Methane [CH4]) concentrations in the air. The MQ-4 can detect natural gas concentrations anywhere from 200 to 10000ppm.This sensor has a high sensitivity and fast response time. The sensor's output is an analog resistance. The drive circuit is very simple; all you need to do is power the heater coil with 5V, add a load resistance, and connect the output to an ADC.In Gas module, MQ-4 is a low power heat conduction gas sensor. The working principle is its resistance value fluctuate when gas concentration changes, the relationship is almost a linear one. MQ-4 is a high precision, low-power unit with heating circuit, the voltage is Vc: 5.0V0.1V VH: 5.0V0.1V, load resistance is 51 , preheating time is Over 48 hours static power consumption is less than 900mW, and working temperature range is -40 ~ +70TEMPERATURE SENSORThe DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of -55C to +125C and is accurate to 0.5C over the range of -10C to +85C. In addition, the DS18B20 can derive power directly from the data line ("parasite power"), eliminating the need for an external power supply.Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.

HUMIDITY SENSORHumidity is the presence of water in air. The amount of water vapor in air can affect human comfort as well as many manufacturing processes in industries. The presence of water vapor also influences various physical, chemical, and biological processes. Humidity measurement in industries is critical because it may affect the business cost of the product and the health and safety of the personnel. Hence, humidity sensing is very important, especially in the control systems for industrial processes and human comfortTo mention moisture levels, variety of terminologies are used. The study of water vapour concentration in air as a function of temperature and pressure falls under the area of psychometrics. Psychometrics deals with the thermodynamic properties of moist gases while the term humidity simply refers to the presence of water vapour in air or other carrier gas.

Humidity measurement determines the amount of water vapor present in a gas that can be a mixture, such as air, or a pure gas, such as nitrogen or argon. Various terms used to indicate moisture levels are tabulated in the table below:

SOFTWARE

VISUAL BASIC 6

VISUAL BASIC is a high level programming language whichevolved from the earlier DOS version called BASIC. BASIC means Beginners' All-purpose Symbolic Instruction Code. It is a relatively easy programming language to learn. The code looks a lot like English Language. Different software companies produced different versions of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, people prefer to use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6 . We also have VB.net, Visual Basic 2005, Visual Basic 2008 and the latest Visual Basic 2010 . Both Vb2008 and VB2010 are fully object oriented programming (OOP) languages.

What programs can you create with Visual Basic 6?With VB 6, you can create any program depending on your objective. For example, if you are a college or university lecturer, you can create educational programs to teach business, mathematics, science, economics, engineering, computer science, accountancy , financial management, information system and more to make teaching more effective and interesting. For example, you can create mathematical programs such as Geometric Progression, Quadratic Equation Solver, Simultaneous Equation Solver

HYPERLINK "http://www.vbtutor.net/VB_Sample/simuleq.htm" ,Prime Number, Factors Finder, Quadratic Function Graph Plotter and so on. For science teacher, you can create simulation programs such as Projectile, Simple Harmonic Motion, Star War etc. If you are in business, you can also create business programs such as inventory management system , Amortization Calculator , investments calculator, point-of-sale system, payroll system, accounting program and more to help manage your business and increase productivity. For those of you who like games , you can create those programs such as slot machine, reversi, tic tac toe and more. Besides, you can create multimedia programs such as Smart Audio Player, Multimedia Player and so on. Indeed, there is no limit to what program you can create ! There are many such programs in this tutorial, so you must spend more time on the tutorial in order to learn how to create those programs.

Visual Basic Graphical User Interface (GUI)

The graphical user interface describes anything your application displays to the user. It is the primary way you interact with the user and allow him or her to interact with you. Creating great GUI's is something Visual Basic is amazing at. You can create professional interfaces with minimal effort. Learn how with these UI Visual Basic tutorials.

Graphical User Interfaces have been around for many years. As you develop more and more advanced applications it is worth your time to focus on your VB6 UI design. This includes understanding how each of the visual basic ui components work (such as buttons, textboxes, combo boxes, images, menus, etc.). This also includes understanding the different vb6 ui containers (such as Tabsets, Panels, status bars, grouping boxes, etc.) By understanding all of these components individually you will have a good knowledge of what can and can't be done.

From here you can focus on how your VB6 GUI fits together as a whole. For example what is the best way to layout a specific form using your individual input controls, labels, and grouping controls. Where should headings go? What order is the user most likely to want to enter their data? What should the tab order be? What controls should be shown vs collapsed? These are all questions a UI programmer needs to think through. Even though UI in Visual Basic is much easier than in many other languages, we as developers need to carefully think through what is most important to our end user and focus on these things above all else.

SOFTWARE DESIGN FLOW

In software design, communication protocol layers have the energy conservation for the center. Take the communication between the sensor nodes and the network coordinator as an example to introduce the flow of communication between the ZigBee modules. Before making communication, ZigBee module need effective initialization, The initialization process between ZigBee sensor nodes and the network coordinator shown in Figure 3. During initialization, the network coordinator issues a active signaling request to connect the sensor nodes. After the sensor nodes successfully receive and verify a data frame and MAC command frames. Return Acknowledgment frame to the sink node, the sensor nodes ZigBee module is in sleep mode. After initialization, ZigBee module information processing as shown in Figure 4, the network coordinator is from the working mode to waiting for connection request signaling for the response of the sensor node, and on the regular time, the sensor nodes take the initiative request to connect the network coordinator and report the detected security information inside the mine to the network coordinator.The communication between sensor nodes and sink nodes, and exchange between sink nodes and

networks coordination are similar. Software design mainly programmed with C language combining Lab view is responsible for the collected data display, analysis and storage etc.

ADVANTAGES

Devices can be operated from anywhere in the world.

Efficient and low cost design.

Low power consumption.

Real time monitoring.

The system is very simple.

Easy to operate.

Data is more secure.

High transmission rate.

Larger distance is covered.

Highly reliable.

APPLICATIONS Can be applied to the person who are working in underground

Can be applied at any working condition

Coalmines

Industries

Tunnels

CONCLUSIONSThe Present work, coal mine safety monitoring system based on wireless sensor networks, and hardware and software design of wireless sensor network are described in detail, this system can detect concentration of the gas, temperature, humidity, wind speed and trace the location of miners in underground mine tunnels. Wireless sensor networks applied in monitoring coal mine security breaks through the traditional methods and ideas, which improvesthe practical ability and flexibility of monitoring system.

This system not only can monitor all kinds of parameters under the coal mine, but also can alarm

automatically when environment parameters are abnormal to exceed the limitation, which help improve the level of monitoring safety production and reduce accident in the coal mine. Therefore, the coal mine Safety Monitoring system put forward in this article quite meets the need of coal mine safety monitoring. Traditional mine security system can be effectively replaced by the surveillance and safety system proposed in the paper. The Example model messages to the registered mobile are shown in Fig 9 & 10. Along with Temperature and Humidity used get the alerts regarding moistures and hazardous gases if detected at the Site of the Sensor node. This System can extended for multiple tunnels by using sensor network.ACKNOWLEDGEMENTSThe authors would like to thank the anonymous reviewers for their comments which were very

helpful in improving the quality and presentation of this paper.REFERENCES:

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