Saturday, April 6, 2013

Sms Controlled Multipurpose Isolated I O board 8 output 4 input

Project code:-E65 Project Cost:- INR:- Rs.12000/- USD:- 300$

Sms Controlled Multipurpose Isolated I/O board 8 output / 4 input

the advancement in technologies in wireless communication many
products are available in the market to make the human life more
comfortable. One of my friend asked me to design a project for him .His
only requirement was to switch ON/OFF his irrigation pump ,which is
two km away from his house. I could not find the radio module which
could cover this distance So I decided to design sms controlled
project. I used sim300 gsm module which is readily available in the
electronic market. His only requirement was to switch ON/OFF single
pump, and feedback via sms whether the pump has actually switched ON
or not.

Sms Controlled Multipurpose Isolated I/O board 8 output / 4 input Block DiagramSms Controlled Multipurpose Isolated I/O board 8 output / 4 input Block Diagram

designed a relay circuit using 89c51 microcontroller Which could be
switched on by single mis call to the device and can also be switched
off by another miscall. It saves my talktime and money. I used to get
the sms from the moter starter contactor panel when it actullay
becomes on, that gives me confirmation that the motor is on.
it gave me a thought to design the present project which could be used
in various application areas depends upon the individual requirement
in the field of agriculture
,lighting,security,telecommunication,access and safety both
industrial,commercial and in residential area.
Designed for control
and sensing applications, this project provides 8 relay outputs and 4
optically isolated inputs. It can be used in various applications
including load contact closure and external voltage sensing.
Connection to the isolated inputs and relay outputs is via “pluggable
type” screw terminal blocks The project presented here is based on
world’s most powerful intel’s mcs-51 family of microcontroller atmel
at89c51.In this project we are using AT 89C2051
microcontroller,since this controller has two ports are more than
enough for our project
Application area: the project can be used for various application wherever you require control using pc.
1 hotel power management
2.street light management
3.home automation
4.load shedding
5. High voltage grid control
6. Industrial automation
7.electro,hydrolic and pneumatic valve control
8. Robotic control and many more All the above operation are possile from the any mobile phone by sms
circuit is connected to gsm modem through rs232 cable to Dshall 9 pin
connectror connected on both sides. ic max 232 is a level conver
ter ic to convert ttl level data to +12v and –12v level for complete
details on this ic, refer to manufacturer’s data sheet
Port 3.0 is rxd pin to receive data serially and port3.1 is to transmit data serially
Circuit is driven by 9v 1 AMP transformer connected to pcon1
Diode d1-d4 forms bridge circuit c1 ,c2,c3 and c4 are filter capacitors
7805 is 5v regulator ic to give stablised supply to
microcontrollerLD1 LED is a power indication led. Crystal gives the
necessary clock to micro-controller.
diodes d1 to d4 are power
recifire diodes connected in bridge circuit c1 is a filter capacitor
.input to the bridge rectifire is 9v 1 ampere transformer. Out put of
the bridge rectifire and capacitor is 12v dc. All our relays are
operated by 12v dc. Relay output can be connected to any 250v 7 ampere
load.please donot cross this limit other wise you will damage the
relay circuit.
Ic2 is atmel at 89c2051 microcontroller. It has two
ports port1 pin number 12 to 19 and port 3 pin number 2,3,6,7,8,9 and
11. This controller has inbuilt uart(universal
synchronous,asynchronous receiver transmitter, and pin no 2 is rx pin
and pin number 3 is tx pin of the uart. Through these two pins
micro-controller is able to communicate with the ibm pc comport.
Communication boud rate is 9600 bits per second.
Port 1 controlls all our relays.out put of this port is pulled high through pullup resistors
arrays(single in line resistor array) hense the outout of pin no 12
to 19 are by default high( at 5v logic) ALL relays stays off on power
up. All the relay driver circuits are similar I will explain one
of then here .
Q1 to q16 all are npn general purpose transisters.
Npn transister will become on when base is high. If you refer circuit
diagram q1 base is driven by r3 connected to pin no 12 of the ic2 as
this pin is at logic high , q1 is on(conducting) and it’s collector
remains at low logic(transister acts as switch,very low resistance
between emitter and collector),resulting base of the transister is low
and transister q2 is in off state(non-conducting). To switch on Q2,
we have to switch off q1. To switch off the q1 the program inside the
micro-controller must bring the logic at pin number 12 to low logic.
q1 will become off and q2 base will get high logic through r4 and
will become ON. relay coil of rl1 will get energised as the current
will pass through coil , q2 transister collector and emitter to
ground. Normally open contact will close the connection. Load should
be connected to the out put of the contacts on CON1.diode d5 connected
across the relay coil is to proctect the circuit from the induced emf
generated by the relay coil during on/off operation.ld2 ic relay ON
indication led r5 is a voltage dropping resistor.
All the relay circuit works in the same manner.
max 232 ic is a level converter ic. IBM pc com port is designed for
telephone network which works on 12v dc where as our controller logic
is at 5v we need to convert this data to +12 &-12 logic before it
is sent to pc this ic has transreceiver level converter. Transmitter
convert the TTL logic to com port logic and receiver part convert the
signals coming from pc to TTL level before it is given to
All the components connected around this ic is as per the application notes given in the datasheet by the manufacturer..
c5 and r1 gives the required reset pulse to microcontroller.Crystal
x1 along with capacitor c6 and c7 gives the required clock pulse to
Resistances connected to indication leds are current limiting resistors.
isolated inputs are connected through opto couplers ic4 to ic7.
output of the opto-coupter are connected to p3.2,p3.3,p3.4 and p3.7
respectively. In1 to in4 are connected to the normally open contact of
the device(sensor controller) you want to monitor . when ever contact
is made led inside the opto coupler will glow and collector inside
will pull the microcontroller pin to logic low, this is the active
state of the device. You can test this by shorting in1 to in4 pins by a
piece of wire and give command from your computer you will get the
proper response as mentioned in the command section.
switch on devices, You can send sms to the device as ON1,ON2,ON3
and so on .T0 switch off devices send sms as OFF1,OFF2,OFF3 and so on .
to get the response from the actuating device if connected to the
input terminals you will receive sms on your mobile phone like
‘device1 is on’ or ‘device2 is off ’ etc.
Commnication between
SIM300 modem and microcontroller takes place via serial port Using
Sim300 AT command set. Which can be downloaded from the official
SIMCOM site.
Some are given here ,can be tried on pc using hyperterminal.
SIM300 AT Command Set
SMS commands
Demonstration Syntax Expect Result
Set SMS system into text mode, as
opposed to PDU mode.
Send an SMS to myself.
>This is a test
Unsolicited notification of the SMS
Read SMS message that has just arrived.
Note: the number should be the same as
that given in the +CMTI notification.
“+8613918186089”, ,”02
This is a test
Reading the message again changes the
status to “READ” from ”UNREAD”
“+8613918186089”, ,
This is a test
Send another SMS to myself. AT+CMGS=”+861391
>Test again
Unsolicited notification of the SMS
Listing all SMS messages.
Note:”ALL” must be in uppercase.
, “02/01/30,20:40:31+00”
This is a test
UNREAD”,” ”,”+861391818
, “02/01/30,20:45:12+00”
Test again
Delete an SMS message. AT+CMGD=1 OK
List all SMS messages to show message
has been deleted.

Test again

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