prepaid energy meter with gsm interface

Prepaid Energy Meter with GSM Interface

http://www.edgefxkits.com/


Introduction

The project has been introduced in the power sector to effectively record the units consumed for billing purposes and also monitor several other factors to reduce power theft and minimize losses that occurs due to conventional electromechanical energy meters. This is a multipurpose project that integrates all the functions including a prepaid billing arrangement and automatic message sending system to the utility company.

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Block Diagram







Hardware Requirements Microcontroller (AT89C52/S52)

Max232 GSM module LCD(16x2) LED Crystal Oscillator Resistors Capacitors Diodes







Hardware Requirements Transformer

Regulator Opto Isolator Energy Meter Lamp push buttons.







Software Requirements

Keil compiler

Languages: Embedded C or Assembly







Power Supply


230 V AC 50 Hz

5V DC

12V step down transformer

Filter(470µf)

5v RegulatorBridge rectifier

A power supply is an electronic device that supplies electric energy to an electrical load.






Power Supply


The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters.






Power Supply

A DC Power Supply Unit (commonly called a PSU) deriving power from the AC mains (line) supply performs a number of tasks:

• It changes (in most cases reduces) the level of supply to a value suitable for driving the load circuit.

• It produces a DC supply from the mains (or line) supply AC sine wave.

• It prevents any AC from appearing at the supply output.







Parts of a Power Supply The output voltage is kept at a constant level, independent of

changes in:

• The AC supply voltage at the supply input.

• The Load current drawn from the supply output.

• Temperature.







Energy Meter


An energy or electric meter is a device that measures the amount of electrical

Energy consumed by a residence, business, or an electrically-powered device.

Electric meters are typically calibrated in billing units, the most common one being the kilowatt hour.

Periodic readings of electric meters establish billing cycles and energy used during a cycle.






MICROCONTROLLER

It is a smaller computer Has on-chip RAM, ROM, I/O ports. etc..

RAM ROM

I/O Port

TimerSerial COM Port

Microcontroller

CPU

A single chip







Internal Structure af A Micro Controller







Energy Meter


An energy or electric meter is a device that measures the amount of electrical

Energy consumed by a residence, business, or an electrically-powered device.

Electric meters are typically calibrated in billing units, the most common one being the kilowatt hour.

Periodic readings of electric meters establish billing cycles and energy used during a cycle.






Microcontroller AT89S51/52


Microcontroller AT 89S51 IC has several benefits and advantages, including high-level constraints, external components hardware less, ease of programming.

And cost-efficient. AT 89S51 IC has an internal program that is easy to remove and re-programmed over and over - again.

In this plane AT 89S51 IC serves as the central control of all aircraft activity. Starting from the timer to control the length of the electrode work.

In this plane AT 89S51 IC is also used as modifiers for the thermal sensor temperature is converted in units of mineral content that is displayed in the form of seven segment displays.






Features of AT89S51/52


Compatible with MCS®-51 Products

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 10,000 Write/Erase Cycles

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

256 x 8-bit Internal RAM

32 Programmable I/O Lines






Features of AT89S51/52


32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Full Duplex UART Serial Channel

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer






IR LED


An IR LED, also known as IR transmitter, is a special purpose LED that transmits infrared rays in the range of 760 nm wavelength.

Such LEDs are usually made of gallium arsenide or aluminum gallium arsenide.

They, along with IR receivers, are commonly used as sensors.

The appearance is same as a common LED.






IR LED


Since the human eye cannot see the infrared radiations.

It is not possible for a person to identify whether the IR LED is working or not, unlike a common LED.

To overcome this problem, the camera on a cell phone can be used.

The camera can show us the IR rays being emanated from the IR LED in a circuit.






Photo Diode


A photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation.

Photodiodes are similar to regular semiconductor diodes except that they may be either exposed (to detect vacuum UV or X-rays) or packaged with a window or optical fibred connection to allow light to reach the sensitive part of the device.






BC547


The BC547 transistor is an NPN Epitaxial Silicon Transistor.

The BC547 transistor is a general-purpose transistor in small plastic packages.

It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.

Whenever base is high, then current starts flowing through base and emitter and after that only current will pass from collector to emitter






DB9 Connector


The DB9 (originally DE-9) connector is an analog 9-pin plug of the D-Sub miniature connector family (D-Sub or Sub-D).






MAX 232


The MAX232 is an integrated circuit that converts signals from an RS-232serial port to signals suitable for use in TTL compatible digital logic circuits.

The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals .

When a MAX232 IC receives a TTL level to convert, it changes a TTL Logic 0 to between +3 and +15V, and changes TTL Logic 1 to between -3 to -15V, and vice versa for converting from RS232 to TTL.






GSM Communication


The term GSM usually means the GSM standard and protocols in the frequency spectrum around 900MHz.

Mobile Station:

The MS is the physical equipment used by a subscriber, most often a normal hand-held cellular telephone.

Base Transceiver Station:

The BTS comprises the radio transmission and reception devices, and also manages the signal processing related to the air interface.






GSM Communication







GSM Modem


A GSM modem is a specialized type of modem which accepts a SIM card, and operates over a subscription to a mobile operator, just like a mobile phone.

From the mobile operator perspective, a GSM modem looks just like a mobile phone.

When a GSM modem is connected to a computer, this allows the computer to use the GSM modem to communicate over the mobile network.

While these GSM modems are most frequently used to provide mobile internet connectivity, many of them can also be used for sending and receiving SMS and MMS messages.

http://www.edgefxkits.com/gsm-based-projects








If an 8-bit data bus is used the LCD will require 11 data lines (3 control lines plus the 8 lines for the data bus).

The three control lines are referred to as EN, RS, and RW.

Liquid Crystal Display (LCD)







Liquid Crystal Display (LCD) Diagram







Working Principle


This is a multipurpose project that integrates all the functions including a prepaid billing arrangement and automatic message sending system to the utility company.

It may please be noted that it is truly not a usable commercial product engaging actual prepaid card but uses a set of switches for understanding the technology implemented behind it.

This project uses an 8051 microcontroller to which a GSM modem is interfaced .

From here the message is sent to the phone number that is auto saved by giving a missed call to the SIM number present in the GSM modem.






Working Principle


There are a set of pushbuttons, which are used to load, any recharge amount required.

Such arrangement is in lieu of an actual prepaid card for demo purposes.

By pushing those buttons one can easily recharge the amount.

As soon as the microcontroller receives any recharge amount, a switch is set , to deliver power to the load.

Thereafter consumption of the load power is calculated by the energy meter, which is interfaced to the microcontroller through an Optical Isolator IC.






Working Principle


The microcontroller program then starts to deduct the recharge amount as per the consumption of load power.

Once the recharge amount reaches to zero then the microcontroller cuts the power supply to the load through a relay driven duly by a NPN transistor

And also sends a message to the phone number stored that contains all the billing information.






Further Enhancement


The concept can further be extended by integrating a RFID smartcard where in each card is provided to automatically recharge the amount and send the same information via GSM module to the respective phone number stored.






Conclusion Prepaid Energy Meter with GSM Interface was designed and implemented. The

concept can further be extended by integrating a RFID smartcard wherein each card is provided to automatically recharge the amount and send the same information via GSM module to the respective phone number stored.


http://www.edgefxkits.com/prepaid-energy-meter-with-gsm-interface

http://www.edgefxkits.com/prepaid-energy-meter-with-gsm-interface





prepaid energy meter with gsm interface

Engineering