WIRELESS ACCESSOR

                                                                               

  ABSTRACT:

      Most of the systems are getting automated these days, why not our present billing system? This made us to think about the concept of Wireless accessor. Now a days reading from electric meters are taken from electricity board (Accessors). This could be automated by the advancement in wireless Technologies. The present billing system leads to wastage of man power and cause in wireless Technologies. The present billing system leads to wastage of man power and cause inconvenience to the society. The money spent on these accessors can be avoided. Our system will provide solution to all of these problems. Wireless Accessor can be regarded as the reading of a meter by a means that does not require physical access or visual inspection of the meter. The electric meter readings are converted into signal suitable for transmission with the help of suitable sensors and they are transmitted to EB station. The reading from the meter will be transmitted through powerful transmitters, receivers and repeaters. Our system also includes special features to indicate the power cut and to avoid power theft. This wireless accessor when implemented is sure to develop a modern society.
 

ITNRODUCTION:

.          The present world is moving towards a new era of automation. Most of the systems existing today are automized with the help of new technologies for the purpose of safety and security. These modern systems have many advantages and they solve lot of existing problems. We have taken one such problem and have tried to solve them with the help of new technologies. Accessor is a person who goes to each and every home to take the EB (electricity board) reading. We have imagined a world with wireless accessor 

PRESENT BILLING SYSTEM:

          Even systems of less importance are getting modernized these days. But our government still follows old method to note the EB meter readings. Main disadvantage is the money spent on these human accessors. There are 227 districts and each of them has more number of accessors depending on the size of the city. Imagine the amount spend for them as their salary. Hence we can replace these human accessors by wireless networks using sensors.

          Moreover the accessor has to go to each and every house and seek permission to take the meter readings. This cause wastage of time for the accessor and unwanted disturbances for the people. There are also some people who cheat the government. They stop meter from running and the use electricity, so that their EB bill can be reduced. For all these problems the solution is going to be wireless accessor. This could be brought into reality by our WIRELESS ACCESSOR.

  

WIRELESS METER READING: 

          Wireless meter reading systems was even tested 30 years ago with a group of utilities. Though the experiments were successful, it was not economical at that time. Hence the costly program was not a great success at that time.

OUR CONTRIBUTION:

          We can give a code for each and every house. EB meters will have a disc which rotates continuously. It will have a red dot which will indicate the completion of one unit. We have decided to attach a spike or metal to that red dot.

      This metal will cut the IR sensors. Each time it cuts the IR sensors, a counter will be incremented. This counter is then will be attached to a transceiver. A six or seven bit code will be given to every house

     

  EXAMPLE CODEWORD:

      3   2    6    2    0   9  

      First bit may denote the code of the main area. Second bit may denote the code of the sub area. Third may denote the street number. Remaining may denote the house number. This method could be adjusted and altered according to our convenience. If all the transceivers transmit their data at the same time, there will be jamming of signals. Receiver in the EB station will not receive the proper data. It will finally result in chaos. It is here the comparator circuit comes to play.

  

HOW OUR SYSTEM WORKS:

      The codeword has to be transmitted from EB station. It will be received by all the receivers in all houses. Each comparator circuit in each house will be given a codeword. It will compare its codeword with the codeword transmitted from EB station. A counter is attached to the EB meter. If both the codes are equal, it will transmit the counter value to the EB station and reset the counter, else it will remain passive. Since the codes are unique, only one house is going to transmit its EB reading. When the station had received the EB reading, it can start to transmit the next codeword to get its next reading.

      Finally we are going to get EB readings by using the IR sensors and wireless networks. Thus we can avoid the use of human accessors and can shift to this new concept of wireless accessor. Power supply status will also be transmitted from EB station to all the houses if there is a power cut, Power of EB station and power supply in the houses are given to Ex-or gate. If output is one then it means that power is coming from station, but it has not reached the house. So there should be some problem on the way.

          Power theft is another important criterion that has been considered in our project. We have used a magnetic proximity sensor to prevent the act of placing of magnets and to make the meter run slowly. The EB department can then send some people to find and rectify the mistake. This is another use of this system by which problem of power failure can be solved. We can also bring a method by which EB bills could be paid through internet, so that every thing can be done by sitting in your chair.
 

WIRELESS METER READING SYSTEMS CONSIST OF THREE PRIMARY COMPONENTS: 

      METER INTERFACE MODULE with power supply, meter sensors, controlling electronics and a communication interface that allows data to be transmitted from this remote device to a central location. This communication interface is bi-directional and allows central office signals to be received by the remote unit as well.

      COMMUNICATIONS SYSTEMS used for the transmission of data and control send signals between the meter interface units and central office. Typically, such communications is in the form of wireless signals. Telephone, power line carrier (plc) or cable television can also be used. But they have many disadvantages. Hence we go for wireless transmission. The system components in the communications system depend on the type of wireless communication used.

      CENTRAL OFFICE SYSTEMS EQUIPMENT including modems, receivers, controllers and host computer. Many utilities have for some time been taking advantage of electronic meter reading systems using hand-held data terminals that communicate with a central controller via phone lines. There is great similarity between the host side electronic meter reading and wireless meter reading system function.
 

FUNCTIONAL BLOCKS:

      There are three major building block functions that the meter interface and related electronics must perform. These are common to other utilities like gas and water readings. Thus this wireless meter reading system is not only used for EB readings, but also can be used for lot of other domestic applications. First, an electromechanical or electro-optical interface must be incorporated into or attached to the meter. We are using IR sensors instead of this interface. This converts information conveyed by the meter’s mechanical register indexes, or dial readings, into electronic signals which may processed, manipulated, stored and transmitted. 

CONTROLLER UNIT:

      The second functional building block is a controller unit consisting of a low-voltage power supply, signal processing electronics (IR sensors), microcomputer, random access memory and program memory used to store the real-time run or operating system program. The controller unit used process the signals originating from the meter’s electromechanical or electro-optical interface device

TRANSMISSION AND RECEPTION:

        The third functional building block is the communication scheme and its associated transmit/receive electronics. Generally, meter-to-utility host communications use one or more transmission techniques: telephone, power line carrier, radio frequency through the airwaves, or television cable. There are many sub-categories of each of these communication forms having to do with data flow, modulation techniques, distance from remote site to central station and data transmission rates. We are going to implement the communication through radio frequency. 

PURPOSE OF ‘IR’ SENSORS:

      The wireless accessor system starts at the meter. Some means of translating readings from rotating meter dials into digital form is necessary in order to send digital metering data from the customer site to a central point. The meter that is used in a wireless accessor system is the same ordinary meter used for manual reading. The one difference is the addition of some device to generate pulses relating to the amount of consumption monitored, or generate an electronic, digital code that translates to the actual reading on the meter dials. That device is going to be IR sensors. 

VARIOUS COMMUNICATION METHODS:

      The four communica5tion methods used for meter reading have various strengths and weaknesses.

     TELEPHONE LINES:

      The disadvantages are that the utility cannot obtain real-time data upon request, nor can the utility reprogram the controller unit or issue control commands as in the case of connect-disconnect or energy management, should these capabilities be incorporated into the system. The primary disadvantages to an outbound communications approach are the capital costs associated with the telephone company’s involvement and the recurring tariffs that telephone companies charge. An additional complication arises in geographical areas served by one electric utility and two or more telephone companies.

     POWER LINE CARRIER:

      Power line carrier techniques may be used successfully and cost effectively for short distances; i.e. from a customer’s meter to a pole or surface-mounted transformer. It is very expensive to pass this data through a distribution transformer and onto the primary distribution lines and the resulting communications is slow due to the narrow bandwidth and mono-directional meaning data is transmitted from the meter to the utility but the utility cannot send data oar control signals back to the meter or associated devices at the subscriber side.

   

 CABLE TELEVISION COMMUNICATION:

      Some tests have shown that this may be a cumbersome and expensive approach. Additionally, many installed cable systems are not configured to pass signals from the subscriber’s site to the central facility. It is expensive to upgrade these systems with wide band bidirectional amplifiers and subscriber interactive taps. 

BEST SUITED RADIO FREQUENCY TECHNIQUE:

      Radio frequency systems make use of small low power RF transmitters or transceivers located at the controller. These may take advantage of licensed or unlicensed portions of the RF spectrum and effective radiated power of the transmitter and distances capable of being traversed will vary as a function of the frequency and power of the remote transmitters and the receiving strategies employed.

A variety of system co9nfigurations have been field tested thus far. The most successful employs a mobile unit operated in a van that sends a wakeup and transmits command to the remote meter units in its range. The remote meter units pick up the signal and responded by sending back requested data to the van’s computer for later uploading and billing.  

IR SENSORS:

      There are different types of IR sensors. We have explained the internal structure of one such sensor. This IR sensor circuits functioned to recognize the 1100Hz IR signal. To achieve this, LTR-3208 NPN phototransistors were each used in a transresistive configuration to yield a more linear response than a sinking or sourcing configuration. The final stage of the IR sensor circuit consisted of a simple half-wave rectifier through which the amplified signal was fed. The rectifier ‘smoothened’ the amplified AC signal to provide a DC output of the IR sensor is given to an inverter (IC 7486) which in turn is given to a counter. This inverter will give output when IR signal is not detected. Thus whenever IR signal is cut by the spike, we will get an output. Thus the mechanical reading is converted to electronic signal well suited for transmission. This output will increment the counter.

TAMPERING, SECURITY AND FRAUD:

      Some customers attempt to manipulate the meter to cause it to under-register or even run backwards, effectively using power without paying for it. Meter when run backwards cases an increase in neutral current at the meter, which is detected and billed at normal rates by standard tamper-resistant meters. Power companies normally investigate discrepancies between the total billed and the total generated, in order to find and fix power distribution problems. These investigations are an effective method of discovering tampering. 

PREVENTION OF POWER PIRATES:

        In recent days, power piracy is increased. Pirates use powerful magnets to reduce the speed of disk rotation, thereby current bill is decreased. These crimes can by prevented by magnetic proximity sensors. When a magnet is brought in the vicinity of the sensor (reed switch), it operates and controls the rest of the switching circuit. In place of the reed switch, one may also use a general-purpose electromagnetic reed relay (by making use of the reed switch contacts) as the sensor.

      When a magnet is brought/placed in the vicinity of the sensor element for a moment, the contacts of the reed switch close to trigger timer IC1 wired in monostable mode. As a consequence its output at pin 3 goes high for short duration and supplies clock to the clock input (pin3) of IC2 (CD4013-dual D-type flip-flop).

This CMOS IC2 consists of two independent flip-flops though here only one is used. Note that the flip-flop is wired in toggle mode with data input (pin 5) connected to the Q (pin 2) output. On receipt of clock pulse, the Q output changes from low to high state and due to this the relay  

WIRELESS  ACCESSOR SYSTEM CAN OFFER THE FOLLOWING BENEFITS: 

      MORE EFFICIENT METER READING – with an automated system, meter readers can significantly improve their productivity over a manual system.

      IMPROVED METER READER SAFETY – meter readers are less susceptible to the dangers of meter reading, including crime, dogs, heat and other issues.

      TAMPER DETECTION –with an AMR system, meter reading can be done for most utilities within several days, enabling the utility to have a better view of consumption levels and identify possible meter tampering.

      BILLING ACCURACY – increased accuracy of an AMR system ensures that readings are done correctly the first time, which improves customer satisfaction.

      ELIMINATE ESTIMATED READS – many utilities can justify going to a monthly read schedule for residential reads, eliminating estimated reads which can often lead to dissatisfied customers.

      MORE EFFICIENT USE OF PERSONNEL – meter readers can be re-deployed into other, higher value and enjoyable functional areas which can improve morale and reduce turnover among staff.

      COST EFFECTIVE – wireless meter reading can also be installed for natural gas, water or other utilities and lakhs of money could be saved.
 

 CONCLUSION:

      Problems are born to be solved. We have taken one such problem pertaining to current Indian scenario and have tried to solve it. If this concept of Wireless Accessor is implemented, it will take our society to next level. Our meters are cost effective. Installing meters will ultimately result in a cost savings to us, which will be passed along to customers. At present, the system is more viable. Advances in solid-state electronics, microprocessor components and low cost surface mount technology have been the catalyst to produce reliable cost effective products capable of providing the economic and human benefits that justify the use of wireless meter reading systems on a large scale. Hence we have chosen this system for our wireless accessor. This wireless accessor is sure to open the doors of HI-FI India.
  

REFERENCES:

• RF Engineering for Wireless networks
• Daniel M.Dobkin.
• Wireless and mobile communication
• Jack M.Holtzman
• David J.Goodman
• www.machinesdirect.com
• www.electroniccircuitdiagrams.com 
• www.antd.nist.gov