AUTOMATIC LPG REFILL BOOKING

ABSTARCT

Booking for a LPG Cylinder Refill and getting it delivered in time is getting

easier. The new system is an Indian Oil initiative to introduce simpler ways for

customers to book for their Indane gas LPG refill. The system is provided and

maintained by Cellular Ltd. SMS (Short Message Service): This too is a 24 x 7

facility where Indane customers can send an SMS from their mobile phone to

register for the service and subsequently book for refills. • If the customer is using

SMS facility for the first time, then SMS IOC < STD Code + Distributor's T e l .

N u m b e r > <Consumer Number> to the unique Idea number for your city. For

example, in case the distributor's telephone number in Delhi is 26024289 and

consumer number is QX00827C, SMS shall be sent as follows: IOC 01126024289

QX00287C. For subsequent bookings, send SMS IOC to the same number. With a

view to provide better services to the customers and to reduce the scope for

irregularities, we have introduced the facility of refill booking through Short

Messaging Service (SMS).and also if an gas leakage is detected automatically

main supply will OFF in order to avoid fire accident.

1. INTRODUCTION

Pervasive computing (also known as ubiquitous computing) brings to light a

new genre of computing where in the comput-er completely pervades the life of

the user. Pervasive compu-ting applications promise seamless integration of

digital infra-structure with their interconnected devices and services into our

everyday lives . In India the supply of LPG through pipelines is not possible due

to shortage of LPG production . As technology being improved many gas agencies

or distributors have implemented IVRS these days although due to daily busy

schedules, cus-tomer finds very difficult to book new cylinder, and also it is very

dangerous when a LPG gas leakage occurs in any domes-tic usage, chemical

industry or in any other applications. This paper provides automatic booking of

LPG cylinder and to overcome the problem of LPG leakage.

IVRS system was borne from general complaints of consum-ers that landline

phones of their distributors were either busy or no one answered the call promptly.

With this system, a con-sumer can approach the gas agency by dialing a toll-free

(or non-free) number and later will have to follow the interactive directions.

Finally, the system will announce the customer number and confirms the customer

number and also confirms the refill of cylinder by pressing 1. Here with most

people who are illiterate find it difficult in handling call or unable to use the higher

end technology .

So our proposal is to complete-ly automate the process of refill booking

without human inter-vention that accordingly will help consumer against foul play.

Our system is also intended to help consumers to upgrade their safety standards,

act in accordance with statutory requirements on environmental commitments and

most impor-tantly the basic function being prevented by accidents and protect life

and property from disasters. The primary objective of our paper is to measure the

gas present in the cylinder when weight of the cylinder reached below the fixed

load, using the pervasive sensors . The gas retailer gets the order for a new cylinder

and the house owner (consumer) receives the message about the same and the

details about the booking proceedings. And the sec-ondary objective is to provide

any malfunction in gas system in order to prevent damage or explosion of LPG.

1.1 EMBEDDED SYSTEM

Embedded systems are controllers with on chip control which consist of

microcontrollers, input and output devices, memories etc. and it can be used for a

specific application. A small computer designed in a single chip is called single

chip microcomputer. A single chip microcomputer typically includes a

microprocessor, RAM, ROM, timer, interrupt and peripheral controller in a single

chip. This single chip microcomputer is also called as a microcontroller. These

microcontrollers are used for variety of applications where it replaced the

computer. The usage of this microcomputer for specific applications, in which the

microcontroller a part of application is called, embedded systems.

Computing systems are everywhere. It’s probably no surprise that millions

of computing systems are built every year destined for desktop computers

(Personal Computers, or PC’s), workstations, mainframes and servers. Thus an

embedded system is nearly any computing system other than a desktop, laptop, or

mainframe computer.

1.2 CHARACTERISTICS OF AN EMBEDDED SYSTEM

1.2.1 SINGLE-FUNCTIONED

An embedded system usually executes only one program, repeatedly. For

example, a pager is always a pager. In contrast, a desktop system executes a

variety of programs, like spreadsheets, word processors, and video games, with

new programs added frequently.

1.2.2 TIGHTLY CONSTRAINED

All computing systems have constraints on design metrics, but those on

embedded systems can be especially tight. A design metric is a measure of an

implementation’s features, such as cost, size, performance, and power. Embedded

systems often must cost just a few dollars, must be sized to fit on a single chip,

must perform fast enough to process data in real-time, and must consume

minimum power to extend battery life or prevent the necessity of a cooling fan.

1.2.3 REACTIVE AND REAL-TIME

Many embedded systems must continually react to changes in the system’s

environment, and must compute certain results in real time without delay. For

example, a car's cruise controller continually monitors and reacts to speed and

brake sensors. It must compute acceleration or decelerations amounts repeatedly

within a limited time; a delayed computation result could result in a failure to

maintain control of the car.

1.3. EMBEDDED PROCESSOR TECHNOLOGY

1.3.1 STANDARD GENERAL PURPOSE PROCESSORS (SGPP)

Standard general purpose processors (SGPP) are carefully designed

and offer a maximum of flexibility to the designer. Programming SGPPs can be

done in nearly every high-level language or assembly language and requires very

little knowledge of the system architecture. As SGPPs are manufactured to high

numbers, NRE is spread upon many units. Nevertheless SGPPs are more expensive

than other solutions like FPGAs or single purpose processors, when used in

products with a large number of selling units. These devices are produced to work

in a broad range of environments since those are not designed to be energy

efficient nor high-performance for specific applications.

Examples for standard general purpose processors are:

Motorola ARM

Atmel AVR

Microchip PIC

Intel Pentium-(I/II/III/IV)-Series

1.3.2. STANDARD SINGLE PURPOSE PROCESSORS (SSPP)

Standard single purpose processors, sometimes called peripherals, are ”off-

the-shelf” pre-designed processors, optimized for a single task, such as digital

signal processing, analog to digital conversion, timing, etc. SSPPs are

manufactured in high quantities, so NRE is spread upon many units. The total costs

per SSPP unit are lower than for custom single purpose processors.

1.3.3. CUSTOM SINGLE PURPOSE PROCESSORS (CSPP)

Custom single purpose processors are designed for a very specific task. This

implies less flexibility, longer time-to-market and high costs. On the other hand

CSPP can be designed to be very small, fast and power-efficient. Examples for

such CSPP are FPGAs or more general PLDs.

1.3.4. APPLICATION SPECIFIC INSTRUCTION-SET PROCESSORS

(ASIP)

ASIPs are basically standard general purpose processors which are extended

by domain-specific instructions. This allows domain-relevant tasks to be

performed highly optimized, while keeping the flexibility of general purpose

processors.

1.3.5. SPECIFIC DESIGN OF EMBEDDED SYSTEM PROCESSOR

When designing an embedded system, usually, the first step is to specify the

intended or required functionality. This is mostly done using natural language,

after the functionality is specified it is formalized in some sort of definition

language such as VHDL or Verilog. Subsequently the resulting design is converted

into hardware or software components which are then implemented.

1.4 IMPORTANCE

Radiation level measurement and monitoring of parameters like temperature,

gas etc., in nuclear power plants is a very important problem that imposes the

implementation of distributed surveillance systems. Usually these type of systems

use networks of sensors for detection. Besides the quality and sensibility of the

sensors, the connections to the monitoring system of large number of sensor raise

some difficulties when wires are used. The advantage of using these radio

technologies are the flexibility in topology implementation and reorganization of

the measurement systems as well as the possibility of realization of portable

devices connected to a measuring and monitoring system with in an area. Security

and accuracy are major concerns. So to overcome these issues the data should be

encrypted to provide security for secret data. In this paper we implement Tiny

Encryption Algorithm (TEA) at the either nodes.

1.5 CONCERNS OF SYSTEM

Three of the major concerns regarding the implementation of wireless

technologies in nuclear power and nuclear reactors include electromagnetic and

radio frequency interference (EMI/RFI), cyber security, and installation issues such

as the coverage of the wireless signal and integration with existing data networks.

Because of the continued evolution of wireless technology and the efforts of the

U.S. Nuclear Regulatory Commission (NRC) and similar governing entities to

maintain up-to-date requirements, the steps performed today to install a wireless

system into a plant may be inadequate five years from now.In nuclear power

plants, redundancy is an important aspect of defense against mishaps. Wireless

sensors provide an easy, cost-effective path to redundancy without compromising

safety. For example, a process parameter may be measured with both wired and

wireless sensors. The wired sensors can be designated as the primary element and

used all the time, and the wireless sensors can be designated as the back-up

element and used only when the wired sensor is unavailable. This has a number of

advantages.

BLOCK DIAGRAM

TRANSMITTER

RECEIVER

HARDWARE DESCRIPTION

5.1 POWER SUPPLY

5.1.1 CIRCUIT DIAGRAM

Fig 5.1.2Circuit Diagram of Power Supply

5.1.2 WORKING PRINCIPLE

The AC voltage, typically 220 rms, is connected to a transformer, which

steps that ac voltage down to the level of the desired DC output. A diode

rectifier then provides a full-wave rectified voltage that is initially filtered by a

simple capacitor filter to produce a dc voltage. This resulting dc voltage usually

has some ripple or ac voltage variation. A regulator circuit removes the ripples

and also remains the same dc value even if the input dc voltage varies, or the

load connected to the output dc voltage changes.

5.1.3 BLOCK DIAGRAM

Fig 5.1.3 Block Diagram of power supply

5.1.4 TRANSFORMER

The potential transformer will step down the power supply voltage (0-230V)

to (0-6V) level. Then the secondary of the potential transformer will be connected

to the precision rectifier, which is constructed with the help of op-amp. The

advantages of using precision rectifier are it will give peak voltage output as DC;

rest of the circuits will give only RMS output.

5.1.5 RECTIFIER

A rectifier is an electrical device that converts alternating current to direct

current or at least to current with only positive value, a process known as

rectification. Rectifiers are used as components of power supplies and as detectors

of radio signals.

5.1.6 BRIDGE RECTIFIER

When four diodes are connected as shown in the power supply circuit

diagram, is called Bridge rectifier. The input to the circuit is applied to the

diagonally opposite corners of the network, and the output is taken from the

remaining two corners.

LOAD IC

FILTERRECTIFIERTRANSFORMER

5.1.7 VOLTAGE REGULATORS

Voltage regulators comprise a class of widely used ICs. Regulator IC units

contain the circuitry for reference source, comparator amplifier, and overload

protection all in a single IC. IC units provide regulation of either a fixed positive

voltage, a fixed negative voltage, or an adjustably set voltage. The regulators can

be selected for operation with load currents from hundreds of milli amperes to tens

of amperes, corresponding to power ratings form milli watts to ten watt. A fixed

three-terminal voltage regulator has an unregulated dc input voltage, V i, applied to

one input terminal, a regulated dc output voltage, Vo , from a second terminal,

with the third terminal connected to ground.

5.1 ATMEGA 8

5.1.1 CONCEPTS OF MICROCONTROLLER :

Microcontroller is a general purpose device, which integrates a number of the

components of a microprocessor system on to single chip. It has inbuilt CPU,

memory and peripherals to make it as a mini computer. A microcontroller

combines on to the same microchip:

The CPU core

Memory(both ROM and RAM)

Some parallel digital i/o

Micro controllers will combine other devices such as:

A timer module to allow the micro controller to perform tasks for certain

time periods.

A serial i/o port to allow data to flow between the controller and other

devices such as a PIC or another Microcontroller.

An ADC to allow the Micro controller to accept analogue input data for

processing.

Micro controllers are :

Smaller in size

Consumes less power

Inexpensive

Micro controller is a stand alone unit ,which can perform functions on its

own without any requirement for additional hardware like i/o ports and external

memory.

The heart of the microcontroller is the CPU core. In the past, this has traditionally

been based on a 8-bit microprocessor unit. For example Motorola uses a basic

6800 microprocessor core in their 6805/6808 microcontroller devices.

In the recent years, microcontrollers have been developed around

specifically designed CPU cores, for example the microchip PIC range of

microcontrollers.

5.1.2 MICROCONTROLLER ATmega8:

PIN DIAGRAM:

5.1.2.1 FEATURES:

High-performance, Low-power Atmel®AVR® 8-bit Microcontroller

• Advanced RISC Architecture

130 Powerful Instructions – Most Single-clock Cycle Execution

32 × 8 General Purpose Working Registers

Fully Static Operation

Up to 16MIPS Throughput at 16MHz

On-chip 2-cycle Multiplier

High Endurance Non-volatile Memory segments

8Kbytes of In-System Self-programmable Flash program memory

512Bytes EEPROM

1Kbyte Internal SRAM

Write/Erase Cycles: 10,000 Flash/100,000 EEPROM

Data retention: 20 years at 85°C/100 years at 25°C(1)

Optional Boot Code Section with Independent Lock Bits

In-System Programming by On-chip Boot Program

Peripheral Features

Two 8-bit Timer/Counters with Separate Prescaler, one Compare Mode

One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and

Capture

Mode

Real Time Counter with Separate Oscillator

Three PWM Channels

8-channel ADC in TQFP and QFN/MLF package

Eight Channels 10-bit Accuracy

6-channel ADC in PDIP package

Six Channels 10-bit Accuracy

Byte-oriented Two-wire Serial Interface

Programmable Serial USART

Master/Slave SPI Serial Interface

Programmable Watchdog Timer with Separate On-chip Oscillator

On-chip Analog Comparator

Special Microcontroller Features

Power-on Reset and Programmable Brown-out Detection

Internal Calibrated RC Oscillator

External and Internal Interrupt Sources

Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down,

and

Standby

I/O and Packages

23 Programmable I/O Lines

28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLF

Operating Voltages

2.7V - 5.5V (ATmega8L)

4.5V - 5.5V (ATmega8)

• Speed Grades

0 - 8MHz (ATmega8L)

0 - 16MHz (ATmega8)

5.1.2.2 PIN DESCRIPTIONS:

1.VCC Digital supply voltage.

2.GND Ground.

3. XTAL1/XTAL2/TOSC1/TOSC2

Port B (PB7..PB0)

Port B is an 8-bit bi-directional I/O port with internal pull-up resistors

(selected for each bit). The Port B output buffers have symmetrical drive

characteristics with both high sink and source capability. As inputs, Port B pins

that are externally pulled low will source current if the pull-up resistors are

activated. The Port B pins are tri-stated when a reset condition becomes

active,even if the clock is not running. Depending on the clock selection fuse

settings, PB6 can be used as input to the inverting Oscillator amplifier and input to

the internal clock operating circuit.Depending on the clock selection fuse settings,

PB7 can be used as output from the inverting Oscillator amplifier.If the Internal

Calibrated RC Oscillator is used as chip clock source, PB7..6 is used as

TOSC2..1input for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is

set.

Port C (PC5..PC0)

Port C is an 7-bit bi-directional I/O port with internal pull-up resistors

(selected for each bit). The Port C output buffers have symmetrical drive

characteristics with both high sink and source capability. As inputs, Port C pins

that are externally pulled low will source current if the pull-up resistors.

PC6/RESET

If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that

the electrical characteristics of PC6 differ from those of the other pins of Port C.If

the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. A low level

on this pin for longer than the minimum pulse length will generate a Reset, even if

the clock is not running. Shorter pulses are not guaranteed to generate a Reset.

Port D (PD7..PD0)

Port D is an 8-bit bi-directional I/O port with internal pull-up resistors

(selected for each bit). The Port D output buffers have symmetrical drive

characteristics with both high sink and source capability. As inputs, Port D pins

that are externally pulled low will source current if the pull-up resistors are

activated. The Port D pins are tri-stated when a reset condition becomes

active,even if the clock is not running.

RESET

Reset input. A low level on this pin for longer than the minimum pulse

length will generate a reset, even if the clock is not running. Shorter pulses are not

guaranteed to generate a reset.

5.1.2.3 ATmega8(L)

AVCC AVCC is the supply voltage pin for the A/D Converter, Port C (3..0),

and ADC (7..6). It should be externally connected to VCC, even if the ADC is not

used. If the ADC is used, it should be connected to VCC through a low-pass filter.

Note that Port C (5..4) use digital supply voltage, VCC.AREF AREF is the analog

reference pin for the A/D Converter.

5.1.2.4 ARCHITECTURAL OVER VIEW

5.3 LCD DISPLAY:

An LCD is a small low cost display. it is easy to interface with a micro-

controller because of an embedded controller (the black blob on the back of the

board). This controller is standard across many displays (hd 44780), which means

many micro-controllers have libraries that make displaying messages as easy as a

single line of code.

Fig 5.3 Schematic view of 16 x 2 LCD display

5.3.1 FEATURES:

5 x 8 dots with cursor

built-in controller (ks 0066 or equivalent)

+ 5v power supply (also available for + 3v)

1/16 duty cycle

b/l to be driven by pin 1, pin 2 or pin 15, pin 16 or a.k (led)

n.v. optional for + 3v power supply

5.3.2 ADDRESS CODE:

Fig 5.3.2 Address code for 16 x 2 LCD display

5.3.3 DETAILS OF 16 X 2 LCD DISPLAY:

Fig 5.3.3Pin details for 16 x 2 LCD display

5.4 KEY PAD (4X1 MATRIX)

This note describes an method of interfacing a matrix keyboard to EZ328

using minimum number of I/O ports. We use a 4x1 matrix keypad as an example.

It requires only five I/O ports. (In general, it takes n+1 ports to interface a nxn

matrix keyboard). It is a low cost solution. No TTL logic ICs are used. The

components mainly used in the interfacing circuitry include only diodes and

resistors which can greatly reduce the system cost and size of the product.

Fig.5.4., schematic view of 4x1 Keypad

Figure 5.4 shows a functional block diagram of the keyboard interface. As

seen in this diagram, there are two major parts.

• Interrupt & interfacing Circuity - generates interrupt to EZ328 when there is a

key pressed and provides connection to EZ328’s I/O ports

• Keyboard matrix - a 4x1 matrix keypad

The interrupt and interfacing circuit includes some diodes, resistors, pull-up

resistors and a NPN transistor.The transistor part is designed as an inverter for

generating interrupt signal to EZ328 when there is a key pressed. There are two

groups of diodes mainly for restricting signal flow in single direction so as to

enable this circuitry to identify the pressed key uniquely. One of these two groups

of diodes have been wired together to provide a “OR” function which in turn

allows any key pressed on each column of the keypad to signal the transistor part

for generating interrupt.

This solution demonstrates a simple mechanism to build a keyboard with

minimum I/O port used. In this application, we use a 4x4 matrix keypad as an

example. It requires only five I/O ports for interfacing. One of them is used for

generating the interrupt signal in the beginning and used as an I/O port for key

scanning operation afterwards. Detail of the method in scanning and identifying

the pressed key will be discussed in the section “SCAN KEYOperation”. It should

also be noted that in this design, EZ328 uses five ports for interfacing but only one

of them requires interrupt capability.

5.4.1 SCAN KEY OPERATION

Five ports are used for key scanning function in this system. One of them

(PD7) is used as the interrupt pin before a key is pressed. Before the key scanning

process starts, all of the I/O ports except the one with interrupt capability is

configured as output high. Then, when there is a key pressed, one of the columns

on the keypad changes state from low to high. As all the columns on the keypad

are wired together to form a “OR” logic to the base of the NPN transistor, it will

generate an active low interrupt signal to EZ328 and initiates the interrupt handler

to scan the pressed key.When the key scanning process begins, one of the five I/O

ports will be configured to output high while the other ports are configured to

input.

The states on all ports are then read and compared with the pattern recorded

in a predefined lookup table in order to locate which key is pressed. If the key is

not found, another port will be configured to output high instead and read the states

again. This process is repeated until all ports have been configured once to output

high or a key is found.Since the circuitry provides feedback paths, one of the input

port will change state from low to high by the output high port and the states

obtained can identify uniquely which key is being pressed.

5.5 ZIGBEE

5.5.1 UART

A universal asynchronous receiver/transmitter, abbreviated UART, is a

type of "asynchronous receiver/transmitter", a piece of computer hardware that

translates data between parallel and serial forms. UARTs are commonly used in

conjunction with communication standards such as EIA RS-232, RS-422 or RS-

485. The universal designation indicates that the data format and transmission

speeds are configurable and that the actual electric signaling levels and methods

(such as differential signaling etc.) typically are handled by a special driver circuit

external to the UART.

5.5.2 ZIGBEE

MIWI is a specification for a suite of high level communication protocols

using small, low-power digital radios based on the IEEE 802.15.4-2003 standard

for Low-Rate Wireless Personal Area Networks (LR-WPANs), such as wireless

light switches with lamps, electrical meters with in-home-displays, consumer

electronics equipment via short-range radio needing low rates of data transfer. The

technology defined by the MIWI specification is intended to be simpler and less

expensive than other WPANs, such as Bluetooth. MIWI is targeted at radio-

frequency (RF) applications that require a low data rate, long battery life, and

secure networking.

Fig.5.5.2 Schematic view of Zigbee

MIWI is a low-cost, low-power, wireless mesh networking standard. First,

the low cost allows the technology to be widely deployed in wireless control and

monitoring applications. Second, the low power-usage allows longer life with

smaller batteries. Third, the mesh networking provides high reliability and more

extensive range. It is not capable of powerline networking though other elements

of the OpenHAN standards suite promoted by openAMI and UtilityAMI deal

with communications co-extant with AC power outlets. In other words, MIWI is

intended not to support powerline networking but to interface with it at least for

smart metering and smart appliance purposes. Utilities, e.g. Penn Energy, have

declared the intent to require them to interoperate again via the openHAN

standards.

Typical application areas include

Home Entertainment and Control — Smart lighting, advanced temperature

control, safety and security, movies and music Wireless Sensor Networks —

Starting with individual sensors like Telosb/Tmote and Iris from Memsic.

5.5.3 DEVICE TYPES

There are three different types of MIWI devices:

MIWI coordinator (ZC):

The most capable device, the coordinator forms the root of the network

tree and might bridge to other networks. There is exactly one MIWI coordinator in

each network since it is the device that started the network originally. It is able to

store information about the network, including acting as the Trust Center &

repository for security keys.

MIWI End Device (ZED):

Contains just enough functionality to talk to the parent node (either the

coordinator or a router); it cannot relay data from other devices. This relationship

allows the node to be asleep a significant amount of the time thereby giving long

battery life. A ZED requires the least amount of memory, and therefore can be less

expensive to manufacture than a ZR or ZC.

5.5.3 SOFTWARE AND HARDWARE

The software is designed to be easy to develop on small, inexpensive

microprocessors. The radio design used by MIWI has been carefully optimized for

low cost in large scale production. It has few analog stages and uses digital circuits

wherever possible.Even though the radios themselves are inexpensive, the MIWI

Qualification Process involves a full validation of the requirements of the physical

layer. This amount of concern about the Physical Layer has multiple benefits, since

all radios derived from that semiconductor mask set would enjoy the same RF

characteristics. On the other hand, an uncertified physical layer that malfunctions

could cripple the battery lifespan of other devices on a MIWI network. Where

other protocols can mask poor sensitivity or other esoteric problems in a fade

compensation response, MIWI radios have very tight engineering constraints: they

are both power and bandwidth constrained. Thus, radios are tested to the ISO

17025 standard with guidance given by Clause 6 of the 802.15.4-2006 Standard.

Most vendors plan to integrate the radio and microcontroller onto a single chip

getting smaller devices.

Fig.5.5.3 Pin connection of Zigbee

5.5.4 ELECTRICAL CHARACTERSTICS:

Fig.5.5.4 Electrical characteristics of Zigbee

5.5.5 DEVICE OVERVIEW

The MRF24J40MA is a 2.4 GHz IEEE Std. 802.15.4™ compliant, surface

mount module with integrated crystal, internal voltage regulator, matching

circuitry and PCB antenna. The MRF24J40MA module operates in the non-

licensed 2.4 GHz frequency band and is FCC, IC and ETSI compliant. The

integrated module design frees the integrator from extensive RF and antenna

design, and regulatory compliance testing, allowing quicker time to market.

5.6 CIRCUIT DIAGRAM OF ZIGBEE

Fig 5.5.6 MRF24J40MA Block Diagram

Fig 5.5.7 Circuit Diagram

5.5.7 FEATURES:

2.4 GHz IEEE Std. 802.15.4™ RF Transceiver Module :

IEEE Std. 802.15.4™ Compliant RF Transceiver .

Supports MIWI®, MIWI™, MIWI™ P2P and

Proprietary Wireless Networking Protocols

Small Size: 0.7” x 1.1” (17.8 mm x 27.9 mm),

Surface Mountable

Integrated Crystal, Internal Voltage Regulator,

Matching Circuitry and PCB Antenna

Easy Integration into Final Product – Minimize

Product Development, Quicker Time to Market

Radio Regulation Certification for United States

(FCC), Canada (IC) and Europe (ETSI)

Compatible with Microchip Microcontroller

Families (PIC16F, PIC18F, PIC24F/H, dsPIC33 and PIC32)

Up to 400 ft. Range

Operating Voltage: 2.4-3.6V (3.3V typical)

Temperature Range: -40°C to +85°C Industrial

Simple, Four-Wire SPI Interface

Low-Current Consumption:

-RX mode: 19 mA (typical)

-TX mode: 23 mA (typical)

-Sleep: 2 µA (typical)

RF/Analog Features:

ISM Band 2.405-2.48 GHz Operation

Data Rate: 250 kbps

-94 dBm Typical Sensitivity with +5 dBm

Maximum Input Level

+0 dBm Typical Output Power with

36 dB TX Power Control Range

Integrated Low Phase Noise VCO, Frequency Synthesizer and PLL Loop

Filter .

Digital VCO and Filter Calibration .

Integrated RSSI ADC and I/Q DACs

Integrated LDO .

High Receiver and RSSI Dynamic Range .

MAC/Baseband Features:

Hardware CSMA-CA Mechanism, Automatic ACK Response and FCS

Check

Independent Beacon, Transmit and GTS FIFO

Supports all CCA modes and RSS/LQI

Automatic Packet Retransmit Capable

Hardware Security Engine (AES-128) with CTR, CCM and CBC-MAC

modes .

Supports Encryption and Decryption for MAC Sublayer and Upper Layer .

5.5.8 Applications

·2.4-GHz IEEE 802.15.4 systems

·RF4CE remote control systems (64-KB flash and higher)

·MIWI systems (256-KB flash)

·Home/Building automation

·Lighting systems

·Industrial control and monitoring

·Low-Power wireless sensor networks

·Consumer electronics

·Health care

GSM MODEM:

Model of gsm modem

• Sim300 - gsm/gprs engine.

• Works on frequencies egsm 900 mhz, dcs 1800 mhz and pcs 1900 mhz.

• Sim300 features gprs multi-slot class 10/ class 8 (optional) and supports the gprs coding

schemes.

Feautures of gsm kit:

This gsm modem is a highly flexible plug and play quad band gsm modem for direct and

as integration to rs232.

• Supports features like voice, data/fax, sms, gprs and integrated tcp/ip stack.

• Control via at commands.

• Use ac – dc power adaptor with following ratings · dc voltage : 12v /1a.

• Current consumption in normal operation 250ma, can rise up to 1amp while transmission.

Introduction:

This document describes the hardware interface of the simcom sim300 module that connects to

the specific application and the air interface. As sim300 can be integrated with a wide range of

applications, all functional components of sim300 are described in great detail. This document

can help you quickly understand sim300 interface specifications, electrical and mechanical

details. With the help of this document and other sim300 application notes, user guide, you can

use sim300 module to design and set-up mobile applications quickly

Product concept :

Designed for global market, sim300 is a tri-band gsm/gprs engine that works on frequencies

egsm 900 mhz, dcs 1800 mhz and pcs1900 mhz. Sim300 provides gprs multi-slot class 10

capability and support the gprs coding schemes cs-1, cs-2, cs-3 and cs-4.

With a tiny configuration of 40mm x 33mm x 2.85 mm , sim300 can fit almost all the space

requirement in your application, such as smart phone, pda phone and other mobile device.

The physical interface to the mobile application is made through a 60 pins board-to-board

connector, which provides all hardware interfaces between the module and customers’ boards

except the rf antenna interface.

The keypad and spi lcd interface will give you the flexibility to develop customized

applications.

Two serial ports can help you easily develop your applications.

Two audio channels include two microphones inputs and two speaker outputs. This can be

easily configured by at command.

Sim300 provide rf antenna interface with two alternatives: antenna connector and antenna pad.

The antenna connector is murata mm9329-2700. And customer’s antenna can be soldered to the

antenna pad. The sim300 is designed with power saving technique, the current consumption to

as low as 2.5ma in sleep mode. The sim300 is integrated with the tcp/ip protocol ，extended

tcp/ip at commands are developed for customers to use the tcp/ip protocol easily, which is very

useful for those data transfer applications.

Sim300 key features at a glance:

Application interface:

All hardware interfaces except rf interface that connects sim300 to the customers’ cellular

application platform is through a 60-pin 0.5mm pitch board-to-board connector. Sub-interfaces

included in this board-to-board connector are described in detail in following chapters:

• Power supply

• Dual serial interface

• Two analog audio interfaces

• Sim interface

Electrical and mechanical characteristics of the board-to-board connector are specified. There we

also order information for mating connectors.

Power supply:

The power supply of sim300 is from a single voltage source of vbat= 3.4v...4.5v. In some

case, the ripple in a transmit burst may cause voltage drops when current consumption rises to

typical peaks of 2a, so the power supply must be able to provide sufficient current up to 2a. For

the vbat input, a local bypass capacitor is recommended.

A capacitor (about 100μf, low esr) is recommended. Multi-layer ceramic chip (mlcc)

capacitors can provide the best combination of low esr and small size but may not be cost

effective. A lower cost choice may be a 100 μf tantalum capacitor (low esr) with a small (1 μf to

10μf) ceramic in parallel, which is illustrated as following figure. And the capacitors should put

as closer as possible to the sim300 vbat pins. The following figure is the recommended circuit.

The following figure is the vbat voltage ripple wave at the maximum power transmit phase, the

test condition is vbat=4.0v, vbat maximum output current =2a, ca=100 μf tantalum capacitor

(esr=0.7ω) and cb=4.7μf

Power supply pins on the board-to-board connector:

Eight vbat pins of the board-to-board connector are dedicated to connect the supply

voltage; four gnd pins are recommended for grounding. Backup can be used to back up the rtc.

Minimizing power losses:

Please pay special attention to the supply power when you are designing your

applications. Please make sure that the input voltage will never drops below 3.4v even in a

transmit burst during which the current consumption may rise up to 2a. If the power voltage

drops below 3.4v, the module may be switched off. Using the board-to-board connector will be

the best way to reduce the voltage drops. You should also take the resistance of the power supply

lines on the host board or of battery pack into account.

Monitoring power supply:

To monitor the supply voltage, you can use the “at+cbc” command which include three

parameters: voltage percent and voltage value (in mv). It returns the battery voltage 1-100

percent of capacity and actual value measured at vbat and gnd.

The voltage is continuously measured at intervals depending on the operating mode. The

displayed voltage (in mv) is averaged over the last measuring period before the at+cbc command

was executed.

Power up and power down scenarios Turn on sim300:

Sim300 can be turned on by various ways, which are described in following

• Via pwrkey pin: starts normal operating mode

• Via rtc interrupt: starts alarm modes

Turn on sim300 using the pwrkey pin (power on):

You can turn on the sim300 by driving the pwrkey to a low level voltage

For period time. The power on scenarios illustrate as following figure.

Turn on sim300 using the rtc (alarm mode):

Alarm mode is a power-on approach by using the rtc. The alert function of rtc makes the

sim300 wake up while the module is power off. In alarm mode, sim300 will not register to gsm

network and the software protocol stack is close. Thus the parts of at commands related with sim

card and protocol stack will not accessible, and the others can be used as well as in normal mode.

Use the at+calarm command to set the alarm time. The rtc remains the alarm time if sim300 was

power down by “at+cpowd=1” or by pwrkey pin. Once the alarm time expires and executed,

sim300 goes into the alarm mode. In this case, sim300 will send out an unsolicited result code

(urc):

Rdy alarm mode:

During alarm mode, using at+cfun command to query the status of software protocol

stack; it will return 0 which indicates that the protocol stack is closed. Then after 90s, sim300

will power down automatically. However, during alarm mode, if the software protocol is started

by at+cfun=1, 1 command, the process of automatic power down will not available. In alarm

mode, driving the pwrkey to a low level voltage for a period will cause sim300 to power down

Turn off sim300:

Following procedure can be used to turn off the sim300:

• Normal power down procedure: turn off sim300 using the pwrkey pin

• Normal power down procedure: turn off sim300 using at command

• Under-voltage automatic shutdown: takes effect if under-voltage is detected

• Over-temperature automatic shutdown: takes effect if over-temperature is detected

Turn off sim300 using the pwrkey pin (power down) :

You can turn off the sim300 by driving the pwrkey to a low level voltage for period time. The

power down scenarios illustrate as following figure. This procedure will let the module to log

off from the network and allow the software to enter into a secure state and save data before

completely disconnect the power supply. Before the completion of the switching off procedure

the module will send out result code:

Power down:

After this moment, no any at commands can be executed. Module enters the power down mode,

only the rtc is still active. Power down can also be indicated by vdd_ext pin, which is a low level

voltage in this mode.

Turn off sim300 using at command :

You can use an at command “at+cpowd=1” to turn off the module. This command will let the

module to log off from the network and allow the software to enter into a secure state and safe

data before completely disconnect the power supply.

Power down:

After this moment, no any at commands can be executed. Module enters the power down mode,

only the rtc is still active. Power down can also be indicated by vdd_ext pin, which is a low level

voltage in this mode

Under-voltage automatic shutdown:

Software will constantly monitors the voltage applied on the vbat, if the measured battery

voltage is no more than 3.5v, the following urc will be presented:

Power low warning:

If the measured battery voltage is no more than 3.4v, the following urc will be presented:

Power low down:

After this moment, no further more at commands can be executed. The module will log off from

network and enters power down mode, only the rtc is still active. Pow

Restart sim300 using the pwrkey pin :

You can restart sim300 by driving the pwrkey to a low level voltage for period time, same as

turn on sim300 using the pwrkey pin. Before restart the sim300, you need delay at least 500ms

from detecting the vdd_ext low level on. The restart scenarios illustrate as the following figure.

Power saving :

There are two methods to achieve sim300 module extreme low power. “at+cfun” is used to set

module into minimum functionality mode and /dtr hardware interface signal can be used to set

system to be sleep mode (or slow clocking mode).

Minimum functionality mode :

Minimum functionality mode reduces the functionality of the module to a minimum and, thus,

minimizes the current consumption to the lowest level. This mode is set with the “at+cfun”

command which provides the choice of the functionality levels <fun>=0，1，4

0: minimum functionality;

1: full functionality (default);

4: disable phone both transmit and receive rf circuits;

If sim300 has been set to minimum functionality by “at+cfun=0”, then the rf function and sim

card function will be closed, in this case, the serial ports is still accessible, but all at commands

need rf function or sim card function will not accessible. If sim300 has disable all rf function by

“at+cfun=4”, then rf function will be closed, the serial ports is still active in this case but all at

commands need rf function will not accessible. When sim300 is in minimum functionality or

has been disable all rf functionality by “at+cfun=4”, it can return to full functionality by

“at+cfun=1”.

Sleep mode (slow clocking mode) :

Through dtr signal control sim300 module to enter or exit the sleep mode in customer

applications. When dtr is in high level, at the same time there is no on air or audio activity is

required and no hardware interrupt (such as gpio interrupt or data on serial port), sim300 will

enter sleep mode automatically. In this mode, sim300 can still receive paging or sms from

network. In sleep mode, the serial port is not accessible.

Wake up sim300 from sleep mode :

When sim300 is sleep mode, the following method can wake up the module. Enable dtr pin to

wake up sim300; If dtr pin is pull down to a low level this signal will wake up sim300 from

power saving mode. The serial port will be active after dtr change to low level about 20m

Receive a voice or data call from network to wake up sim300;

Receive a sms from network to wake up sim300

Rtc alarm expired to wake up sim300;

Max232:

Pin diagram:

Pin diagram of max232

Features:

Meets or exceeds tia/eia-232-f and itu recommendation v.28

Operates from a single 5-v power supply with 1.0-_f charge-pump capacitors

Operates up to 120 kbit/s

Two drivers and two receivers.

±30-v input levels

Low supply current ( 8 ma typical)

Esd protection exceeds jesd 22

− 2000-v human-body model (a114-a)

Upgrade with improved esd (15-kv hbm) and 0.1-_f charge-pump capacitors is available

with the max202.

Description:

The max232 is a dual driver/receiver that includes a capacitive voltage generator to supply

tia/eia-232-f voltage levels from a single 5-v supply. Each receiver converts tia/eia-232-f inputs

to 5-v ttl/cmos levels. These receivers have a typical threshold of 1.3 v, a typical hysteresis of 0.5

v, and can accept ±30-v inputs. Each driver converts ttl/cmos input levels into tia/eia-232-f

levels. The driver, receiver, and

Voltage-generator functions are available as cells.

Logic circuit diagram:

Schematic diagram of max232 chip:

Figure 6 : Schematic diagram of max232

Test circuit:

Waveforms:

CHAPTER 6

SOFTWARE ANALYSIS

6.1 INTRODUCTION TO CODE VISION AVR

CodeVisionAVR is a C cross-compiler, Integrated Development

Environment and Automatic Program Generator designed for the Atmel AVR

family of microcontrollers. The program is a native 32bit application that runs

under the Windows 95, 98, NT 4, 2000 and XP operating systems. The C cross-

compiler implements nearly all the elements of the ANSI C language, as allowed

by the AVR architecture, with some features added to take advantage of specificity

of the AVR architecture and the embedded system needs. The compiled COFF

object files can be C source level debugged, with variable watching, using the

Atmel AVR Studio debugger.

The Integrated Development Environment (IDE) has built-in AVR Chip In-

System Programmer software that enables the automatical transfer of the program

to the microcontroller chip after successful compilation/assembly. The In-System

Programmer software is designed to work in conjunction with the Atmel STK500,

Kanda Systems STK200+/300, Dontronics DT006, Vogel Elektronik VTEC-ISP,

Futurlec JRAVR and MicroTronics' ATCPU/Mega2000 development boards. For

debugging embedded systems, which employ serial communication, the IDE has a

built-in Terminal. Besides the standard C libraries, the CodeVisionAVR C

compiler has dedicated libraries for:

• Alphanumeric LCD modules

• Philips I2C bus

• National Semiconductor LM75 Temperature Sensor

• Philips PCF8563, PCF8583, Dallas Semiconductor DS1302 and DS1307

Real Time Clocks

• Dallas Semiconductor 1 Wire protocol

• Dallas Semiconductor DS1820/DS18S20 Temperature Sensors

• Dallas Semiconductor DS1621 Thermometer/Thermostat

• Dallas Semiconductor DS2430 and DS2433 EEPROMs

• SPI

• Power management

• Delays

• Gray code conversion.

CodeVisionAVR also contains the CodeWizardAVR Automatic Program

Generator, that allows you to write, in a matter of minutes, all the code needed for

implementing the following functions:

• External memory access setup

• Chip reset source identification

• Input/Output Port initialization

• External Interrupts initialization

• Timers/Counters initialization

• Watchdog Timer initialization

• UART initialization and interrupt driven buffered serial communication

• Analog Comparator initialization

• ADC initialization

• SPI Interface initialization

• I2C Bus, LM75 Temperature Sensor, DS1621 Thermometer/Thermostat and

PCF8563, PCF8583,

• DS1302, DS1307 Real Time Clocks initialization

• 1 Wire Bus and DS1820/DS18S20 Temperature Sensors initialization

• LCD module initialization

CONCLUSION:

The product design prototype is constructed and when a Small amount of

LPG is brought near the system, the system sensor detects the leakage and sends

the SMS to housemates and activates the alarm and switches on the exhaust fan.

Also system prototype continuously monitors the LPG level of the cylinder and

books the cylinder automatically through SMS using GSM modem.