GSM
based Automatic meter reading
Abstract
:
GSM based Automatic meter reading is the technology of
automatically collecting data from energy meter and transferring that data to a
central database for billing and/or analyzing. The Transmitter circuit is
connected to the meter which counts the pulses from it and displays it over the
LCD display. The transmitter circuit containing a GSM modem for data
transforming, which transforms the meter reading after each 10 pulses to a
particular number through SMS.
An
additional advanced service is also available, which includes the software
operating on the computer. This software shows the updated reading. User has to
put the unit rate and date of billing, and then this software automatically
calculates the bill and also print it if printer is connected to computer.
Working:
In
this GSM based Automatic meter reading, a led is connected in parallel to the
‘cal’ led of meter reading. This led is paired with a LDR, which acts as an
Optocoupler. the output of LDR is connected to the base of NPN transistor and
the collector output of transistor is connected to the pin P1.0 of
micro-controller. So at each blink of led of meter reading, a signal is passed
to the micro-controller to count the pulses of meter reading. Then
micro-controller updates the reading and displayed it over LCD and also saves
to the EEPROM. The LCD and EEPROM are connected to port 0 of micro-controller.
For transferring the data a GSM modem is used, which sends SMS to the
particular mobile number defined. The micro-controller is programmed to send the
SMS after every 10 pulses of meter reading. The MAX232 is used to interfacing
GSM modem, there is another GSM modem is also available which doesn’t required
MAX232, it can directly connected to micro-controller
Circuit:
Connect the 4 of the optp-coupler to the black wire and pin
5 to the brown wire Connect the black wire to the ground of the circuit board
for the projecks prepaid energy the brown wire carry’s the pulse output
GSM carrier frequencies[edit]
GSM networks operate in a
number of different carrier frequency ranges (separated into GSM frequency ranges for 2G and UMTS frequency bands for 3G), with most 2GGSM
networks operating in the 900 MHz or 1800 MHz bands. Where these bands
were already allocated, the 850 MHz and 1900 MHz bands were used
instead (for example in Canada and the United States). In rare cases the 400
and 450 MHz frequency bands are assigned in some countries because they
were previously used for first-generation systems.
Most 3G networks in Europe operate in the
2100 MHz frequency band. For more information on worldwide GSM frequency
usage, see GSM frequency bands.
Regardless of the frequency
selected by an operator, it is divided into timeslots for individual phones. This allows eight
full-rate or sixteen half-rate speech channels per radio
frequency. These eight radio timeslots (or burst periods)
are grouped into a TDMA frame. Half-rate channels use alternate
frames in the same timeslot. The channel data rate for all 8 channels is 270.833 kbit/s, and
the frame duration is 4.615 ms.
The transmission power in the
handset is limited to a maximum of 2 watts in GSM 850/900 and 1 watt in GSM 1800/1900.
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