Introduction
In this project we will make car security system. Car will work as a sensor . It will give signal to amplifier circuit. Amplifier will give pulse to microcontroller . microcontroller will give serially data through RS232 IC. We will use max232 ic for serial communication between max232 and microcontroller 89s52.
Main circuits in this project are:
Micro controller interface
RS232 circuit
LCD interface
MICROCONTROLLER CONTROL.
About GSM modem
GSM/GPRS Modem
This GSM modem is a highly flexible plug and play quad band GSM modem for direct and easy
integration to RS232. Supports features like Voice, Data/Fax, SMS,GPRS and integrated TCP/IP
stack.
Features
· Quad Band GSM/GPRS
850/900/1800/1900 Mhz
· GPRS multi-slot class 10/8
· GPRS Mobile station class B
· Compliant to GSM Phase 2/2+
o Class 4 (2W@850/900Mhz)
o Class 1(1W@1800/1900Mhz)
· Control via AT commands(GSM 07.07,
07.05 and enhanced AT commands)
· Operation Temperature(-20 deg C to
+55 deg C)
Specifications for Voice
· Tricodec
o Half rate(HR)
o Full rate(FR)
o Enchanced Full rate(EFR)
· Hands-free operation(Echo suppression)
Specifications for Fax
· Group 3, class 1
Specifications for data
· GPRS class 10: max 85.6 kbps(downlink)
· PBCCH support
· Coding schemes CS 1,2,3,4
· CSD upto 14.4 kbps
· USSD
· Non transparent mode
· PPP-Stack
Specifications for SMS
· Point-to-point MO and MT
· SMS cell broadcast
· Text and PDU mode
Power Supply
· Use AC – DC Power Adaptor with following ratings
· DC Voltage : 12V
· DC Current : 1A
· Polarity : Centre +ve & Outside –ve
· Current Consumption in normal operation 250mA, can rise up to 1Amp while transmission.
Interfaces
· RS-232 through D-TYPE 9 pin connector, Serial port baud rate adjustable 1200 to115200
bps (9600 default)
· Stereo connector for MIC & SPK
· Power supply through DC socket
· SMA antenna connector
· Push switch type SIM holder
· LED status of GSM / GPRS module
Getting Started
· Insert SIM card: Press the yellow pin to remove the tray from the SIM cardholder. After
properly fixing the SIM card in the tray, insert the tray in the slot provided.
· Connect Antenna: Screw the RF antenna on the RF cable output provided.
· If voice call is needed, connect the mic and speaker to stereo sockets.
· Connect RS232 Cable: (Cable provided for RS232 communication) Default baud rate is
9600 with 8-N-1, no hardware handshaking. Cable provided has pins 7 and 8 shorted that will
set to no hardware handshaking. In you need hardware handshaking the pins 7-8 can be
taken for signaling.
o Pin 2 is RS232 level TX out
o Pin 3 is RS232 level RX in
o Pin 5 is Ground
o Pin 7 RTS in (shorted to pin 8 in cable for no hardware handshaking)
o Pin 8 CTS out (shorted to pin 7 in cable for no hardware handshaking)
· Connect the power Supply (9-12V) to the power jack. Polarity should be Center +ve and
outer –ve DC jack.
· Network Led indicating various status of GSM module eg. Power on, network registration &
GPRS connectivity.
· After the Modem registers the network, led will blink in step of 3 seconds. At this stage you
can start using Modem for your application.
About MAX232
_ Meet or Exceed TIA/EIA-232-F and ITU
Recommendation V.28
_ Operate With Single 5-V Power Supply
_ Operate Up to 120 kbit/s
_ Two Drivers and Two Receivers
_ ±30-V Input Levels
_ Low Supply Current . . . 8 mA Typical
_ Designed to be Interchangeable With
Maxim MAX232
_ ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
Applications:
TIA/EIA-232-F
Battery-Powered Systems
Terminals
Modems
Computers
description/ordering information
The MAX232 is a dual driver/receiver that includes a capacitive voltage generator to supply EIA-232 voltage
levels from a single 5-V supply. Each receiver converts EIA-232 inputs to 5-V TTL/CMOS levels. These
receivers have a typical threshold of 1.3 V and a typical hysteresis of 0.5 V, and can accept ±30-V inputs. Each
driver converts TTL/CMOS input levels into EIA-232 levels. The driver, receiver, and voltage-generator
functions are available as cells in the Texas Instruments LinASIC. library.
ORDERING INFORMATION
TA PACKAGE† ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP (N) Tube MAX232N MAX232N
SOIC (D)
Tube MAX232D
MAX232
0°C to 70°C
Tape and reel MAX232DR
SOIC (DW)
Tube MAX232DW
MAX232
Tape and reel MAX232DWR
SOP (NS) Tape and reel MAX232NSR MAX232
PDIP (N) Tube MAX232IN MAX232IN
SOIC (D)
Tube MAX232ID
MAX232I
–40°C to 85°C
Tape and reel MAX232IDR
SOIC (DW)
Tube MAX232IDW
MAX232I
Tape and reel MAX232IDWR
† Package drawings, standard packing quantities, thermal data, symbolization, and PCB design
guidelines are available at www.ti.com/sc/package.
MAX232 . . . D, DW, N, OR NS PACKAGE
MAX232I . . . D, DW, OR N PACKAGE
