16-02-2013, 02:55 PM
AIR POLLUTION MONITORING
[attachment=51203]
INTRODUCTION
Over the past quarter century, there has been an exponential increase of industries, and these industries have caused complex and serious problems to the environment. The first and the foremost is the severe environmental pollution which has caused deterioration of atmosphere, climate change, stratospheric ozone depletion, loss of biodiversity, changes in hydrological systems and the supplies of fresh water, land degradation and stresses on systems of food producing, acid rain, and global warming.
The motivation of the project is to build an air pollution monitoring system, so a detection system for multiple information of environment is designed in this project. There is a growing demand for the environmental pollution monitoring and control systems. In view of the ever-increasing pollution sources with toxic chemicals, these systems should have the facilities to detect and quantify the sources rapidly. This project is built for low cost, quick response, low maintenance, ability to produce continuous measurements etc. The main goal of this project is to control the air pollution, hazardous gases and increase awareness about pollution by using air pollution monitoring system. The work is to measure the air pollutants level and temperature range. Then the Acquired air pollutant level from the sensors array will report to the PC. This system is used for acquiring the real-time data from the sensors-array and the physical location, time and date of the sampled pollutants from the GPS module. This information is then encapsulated into a data frame by the microcontroller. Finally the acquired data will report to the PC.
BLOCK DIAGRAM DESCRIPTION
OVERVIEW
This chapter mainly includes the detailed explanation of different blocks included in the block diagram representation of Air Pollution Monitoring. To satisfy the system’s functional and non functional requirements, two major building blocks are needed, namely: a Mobile Data-Acquisition Unit (Mobile-DAQ) and a fixed Internet-Enabled Pollution monitoring Server (Pollution-Server). The Mobile-DAQ consists of a 16-bit single-chip microcontroller integrated with a sensor array using analog ports. The Mobile-DAQ is also connected to a GPS module and a GPRS-Modem using the RS-232 interface.
The blocks mainly included in the block diagram representation of Air Pollution Monitoring system are ATMEGA 16-8 Bit Microcontroller, Sensors, Amplifiers, GPS Module, GSM Modem, LCD Display, RS 232, Pollution Server. The sensors will collect the level of pollutants and then amplify it with the help of amplifiers. This data will be in the form of analog. In order to make this into digital form we feed this analog data to an ADC unit, which will convert the data to digital form. A microcontroller will store this information. Along with GPS details a GPRS modem will packs the digital data and then transmits to the receiver part. The transmitted signal will be received by another GSM modem which is interfaced to the PC with RS232 interface. Finally the data will be displayed on PC.
BLOCK DIAGRAM EXPLANATION
This section gives the explanation about the different blocks represented in the block diagram of air pollution monitoring system. ATMEGA 16 is explained first. It is followed by the signal CO2 sensor, CO sensor, LPG sensor,NO2 sensor, amplifier, GPS module, GSM modem, LCD display, RS 232, pollution server.
ATMEGA16-8 BIT MICROCONTROLLER
AT mega 16 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the AT mega achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
The AT mega 16 provides the following features: 16K bytes of In-system Programmable Flash Program memory with Read-While-Write capabilities, 512 bytes EPROM, 1Kbyte SRAM, 32 general purpose I/O lines, 32 general purpose working registers, a JTAG interface for Boundary-scan, On-chip Debugging support and programming, three flexible Timer/Counters with compare modes, Internal and External Interrupts, a serial programmable USART, a byte oriented Two-wire Serial Interface, an 8-channel, 10-bit ADC with optional differential input stage with programmable gain (TQFP package only), a programmable watchdog Timer with internal oscillator, an SPI serial port, and six software selectable power saving modes. Idle mode stops the CPU while allowing the USART, Two-wire interface, A/D converter, SRAM; Timer/Counters, SPI port, and interrupt system to continue functioning. The power-down mode saves the register but freezes the oscillator disabling all other chip functions until the next external interrupt or hardware reset. In power-saver mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping.
SOFTWARE – C
The program used to implement AIR POLLUTION MONITORING systems is written in C language. C is an imperative (procedural) language. It was designed to be compiled using a relatively straightforward compiler, to provide low-level access to memory, to provide language constructs that map efficiently to machine instructions, and to require minimal run-time support. C was therefore useful for many applications that had formerly been coded in assembly language, such as in system programming. Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a very wide range of platforms, from embedded microcontrollers to supercomputers. Embedded C programming requires nonstandard extensions to the C language in order to support exotic features such as fixed-point arithmetic, multiple distinct memory banks, and basic I/O operations.
SIGNAL CONVERSION UNIT ( ADC)
DC signals are often used as analog representations of physical measurements such as temperature, pressure, flow, weight, and motion. Most commonly, DC current signal is used in preference to DC voltage signals, because current signals are exactly equal in magnitude throughout the series circuit loop carrying current from the source(measuring device) to the load(indicator ,recorder, or controller), whereas voltage signals in a parallel circuit may vary from one end to the other due to resistive wire losses. Furthermore, current sensing instruments typically have low impedances (while voltage-sensing instruments have high impedances), which gives current-sensing instruments greater electrical noise immunity.
In order to use current as an analog representation of a physical quantity, we have to have some way of generating a precise amount of current within the signal circuit .To generate a precise current signal when we might not know the resistance of the loop, we use an amplifier that is designed to hold current to a prescribed value, applying as much or as little voltage as necessary to the load circuit to maintain that value. Such an amplifier performs the function of a current source. An op-amp with negative feedback is a perfect candidate for such a task.
LPG SENSOR
Ideal sensor for use to detect the presence of a dangerous LPG leak in your car or in a service station, storage tank environment. This unit can be easily incorporated into an alarm unit, to sound an alarm or give a visual indication of the LPG
concentration. The sensor has excellent sensitivity combined with a quick response time. The sensor can also sense iso-butane, propane, LNG and cigarette smoke.
GPS MODULE
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.
[attachment=51203]
INTRODUCTION
Over the past quarter century, there has been an exponential increase of industries, and these industries have caused complex and serious problems to the environment. The first and the foremost is the severe environmental pollution which has caused deterioration of atmosphere, climate change, stratospheric ozone depletion, loss of biodiversity, changes in hydrological systems and the supplies of fresh water, land degradation and stresses on systems of food producing, acid rain, and global warming.
The motivation of the project is to build an air pollution monitoring system, so a detection system for multiple information of environment is designed in this project. There is a growing demand for the environmental pollution monitoring and control systems. In view of the ever-increasing pollution sources with toxic chemicals, these systems should have the facilities to detect and quantify the sources rapidly. This project is built for low cost, quick response, low maintenance, ability to produce continuous measurements etc. The main goal of this project is to control the air pollution, hazardous gases and increase awareness about pollution by using air pollution monitoring system. The work is to measure the air pollutants level and temperature range. Then the Acquired air pollutant level from the sensors array will report to the PC. This system is used for acquiring the real-time data from the sensors-array and the physical location, time and date of the sampled pollutants from the GPS module. This information is then encapsulated into a data frame by the microcontroller. Finally the acquired data will report to the PC.
BLOCK DIAGRAM DESCRIPTION
OVERVIEW
This chapter mainly includes the detailed explanation of different blocks included in the block diagram representation of Air Pollution Monitoring. To satisfy the system’s functional and non functional requirements, two major building blocks are needed, namely: a Mobile Data-Acquisition Unit (Mobile-DAQ) and a fixed Internet-Enabled Pollution monitoring Server (Pollution-Server). The Mobile-DAQ consists of a 16-bit single-chip microcontroller integrated with a sensor array using analog ports. The Mobile-DAQ is also connected to a GPS module and a GPRS-Modem using the RS-232 interface.
The blocks mainly included in the block diagram representation of Air Pollution Monitoring system are ATMEGA 16-8 Bit Microcontroller, Sensors, Amplifiers, GPS Module, GSM Modem, LCD Display, RS 232, Pollution Server. The sensors will collect the level of pollutants and then amplify it with the help of amplifiers. This data will be in the form of analog. In order to make this into digital form we feed this analog data to an ADC unit, which will convert the data to digital form. A microcontroller will store this information. Along with GPS details a GPRS modem will packs the digital data and then transmits to the receiver part. The transmitted signal will be received by another GSM modem which is interfaced to the PC with RS232 interface. Finally the data will be displayed on PC.
BLOCK DIAGRAM EXPLANATION
This section gives the explanation about the different blocks represented in the block diagram of air pollution monitoring system. ATMEGA 16 is explained first. It is followed by the signal CO2 sensor, CO sensor, LPG sensor,NO2 sensor, amplifier, GPS module, GSM modem, LCD display, RS 232, pollution server.
ATMEGA16-8 BIT MICROCONTROLLER
AT mega 16 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the AT mega achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
The AT mega 16 provides the following features: 16K bytes of In-system Programmable Flash Program memory with Read-While-Write capabilities, 512 bytes EPROM, 1Kbyte SRAM, 32 general purpose I/O lines, 32 general purpose working registers, a JTAG interface for Boundary-scan, On-chip Debugging support and programming, three flexible Timer/Counters with compare modes, Internal and External Interrupts, a serial programmable USART, a byte oriented Two-wire Serial Interface, an 8-channel, 10-bit ADC with optional differential input stage with programmable gain (TQFP package only), a programmable watchdog Timer with internal oscillator, an SPI serial port, and six software selectable power saving modes. Idle mode stops the CPU while allowing the USART, Two-wire interface, A/D converter, SRAM; Timer/Counters, SPI port, and interrupt system to continue functioning. The power-down mode saves the register but freezes the oscillator disabling all other chip functions until the next external interrupt or hardware reset. In power-saver mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping.
SOFTWARE – C
The program used to implement AIR POLLUTION MONITORING systems is written in C language. C is an imperative (procedural) language. It was designed to be compiled using a relatively straightforward compiler, to provide low-level access to memory, to provide language constructs that map efficiently to machine instructions, and to require minimal run-time support. C was therefore useful for many applications that had formerly been coded in assembly language, such as in system programming. Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a very wide range of platforms, from embedded microcontrollers to supercomputers. Embedded C programming requires nonstandard extensions to the C language in order to support exotic features such as fixed-point arithmetic, multiple distinct memory banks, and basic I/O operations.
SIGNAL CONVERSION UNIT ( ADC)
DC signals are often used as analog representations of physical measurements such as temperature, pressure, flow, weight, and motion. Most commonly, DC current signal is used in preference to DC voltage signals, because current signals are exactly equal in magnitude throughout the series circuit loop carrying current from the source(measuring device) to the load(indicator ,recorder, or controller), whereas voltage signals in a parallel circuit may vary from one end to the other due to resistive wire losses. Furthermore, current sensing instruments typically have low impedances (while voltage-sensing instruments have high impedances), which gives current-sensing instruments greater electrical noise immunity.
In order to use current as an analog representation of a physical quantity, we have to have some way of generating a precise amount of current within the signal circuit .To generate a precise current signal when we might not know the resistance of the loop, we use an amplifier that is designed to hold current to a prescribed value, applying as much or as little voltage as necessary to the load circuit to maintain that value. Such an amplifier performs the function of a current source. An op-amp with negative feedback is a perfect candidate for such a task.
LPG SENSOR
Ideal sensor for use to detect the presence of a dangerous LPG leak in your car or in a service station, storage tank environment. This unit can be easily incorporated into an alarm unit, to sound an alarm or give a visual indication of the LPG
concentration. The sensor has excellent sensitivity combined with a quick response time. The sensor can also sense iso-butane, propane, LNG and cigarette smoke.
GPS MODULE
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.