oOrch Blog

How to hide your password? Must Read… Dont miss

alman — Wed, 14 Oct 2009 14:29:30 +0000

This is a funniest forward mail that I received today from one of my friend… thought interesting and you might like it. Feel free to leave your comments.

HOW TO HIDE YOUR PASSWORD…. ……… …..???? ????

No one can see your passwords or whatever you ‘ re typing

No one can see whatever you ‘ re typing or which website you ‘ re surfing

And the Ultimate is…

Watch Live Oracle OpenWorld & Oracle Develop 2009

AK Lakshmanan — Mon, 12 Oct 2009 11:02:51 +0000

Watch the best of live programming from Oracle OpenWorld, including major keynotes, Q&A with OTN Heavy Hitters, special editions of TechCast, technical keynotes and sessions and more.

Live programming
Sunday 10/11: 12:30 p.m. – 7:00 p.m. PT
Monday 10/12, Tuesday 10/13, Wednesday 10/15: 8:00 a.m. – 5:00 p.m. PT

Replay programming
Monday 10/12, Tuesday 10/13, Wednesday 10/15: 5:00 p.m. – 8:00 a.m. PT

How-To: Build Intelligent Train Engines

alman — Sat, 10 Oct 2009 20:13:40 +0000

We know that the railway network of India is the biggest in south Asia and perhaps the most complicated in all over the world. There are so many different types of trains local, fast, super fast, passenger, goods…. etc. and their so many multiple routs. Although the time table is perfect it is not at all possible to maintain it. And that’s why the train accidents are becoming more and more usual. So why not we add a kind of intelligence to the train engines itself so that it tries to avoid accidents.

The idea is whenever any engine observes a red signal on its track it will start decreasing its speed gradually and stops automatically at some distance from the signal pole. After then when it gets green signal the driver can manually start the train and go on. In the mean time when train has not stopped yet and a red signal becomes green then it crosses the signal pole with low speed and then driver can slowly increase the speed.

So now before the driver observes the red signal the engine itself observes it and automatically starts decreasing speed and then stops. The driver can feel relax in driving because he doesn’t have to take care about red signal. Even if he forgets to take any action on red signal then also we can avoid accidents by the implementation of this idea.

General description:

What we have to do is we have to attach a transmitter with signal pole which will start transmitting signals only when the red light is on. If there is green light no transmission. The engine has a receiver which catches these transmitted signals and takes desire actions.

Both the transmitter and receiver are of RF type with minimum range of 2 Km. so that train can get enough time to decrease its speed and stop before the signal pole with minimum swapping distance of 100-200 mt.

Here in our project we have used IR transmitter and receiver instead of RF for demo purpose. But same idea can be easily implemented with RF also with a little more cost.

Lets first discuss the demonstration model.

Demonstration Model:

The train engine runs on 24V DC motor so that we can easily vary its speed by varying applied voltage. The switching voltage is applied in step of 18 V, 15 V, 12 V and 9 V (min speed). The 230 VAC is step-down to 24 VAC by 12-0-12, 2 Ampere step down transformer. As shown in figure this 24 VAC line runs parallel with track at the top of the train. Movable tapping are taken from this line and fed to the internal circuit of engine. These tapping slides as the train runs on the track and give continuous supply to circuit. The IR sensor is placed at the top of the engine, senses the signals transmitted by IR transmitter attached to signal pole. Train track is straight and 20 ft long. Signal pole is placed at the end of track and train starts from farther end.

Model of Intelligent Train Engines

The project is divided in two parts

Transmitter
Receiver

The transmitter is housed in signal pole and it is activated only when red light is ON.

The receiver is housed in engine which senses the IR signals and takes suitable action.

Signal Pole IR Transmitter:-

The figure shows the schematic diagram of IR transmitter.

Schematic diagram of IR transmitter.

The heart of the circuit is IC555. The main component of the circuit is only IC555.

Connections:

Both ICs are connected in astable mode. The frequency of U2 is 0.5 Hz and U1 is 38 KHz. This is decided by RC components connected with it. The output of U2 is connected with reset pin (4) of U1. Thus the output of U2 controls the operation of U1 means it will switch on or off the output of U1. The output of U1 is fed to two IR LEDs through Darlington pair made up of Q1, Q2 and R5. The 9V DC battery is connected with circuit through SPDT switch SW1 as shown.

Operation:

As shown in figure when SW1 is in position as shown the transmitter is On and also the red LED is also ON. When switch changes its position the red LED and transmitter is off and only green LED will on. When the circuit is energized U2 will start generating high pulse at every 1 sec. as this pulse is fed to reset pin of U1 it will generate 38 KHz square wave and give it to IR leds. IR leds will generate IR beam of 38 KHz for the same time. Thus after every one second the IR beam of 38 KHz is generated for one second only. This cycle repeats till the red light is on.

Note: The range of this transmitter is limited to 10 ft only.

89C51 based IR receiver for Engine:

The IR receiver circuit housed in engine is as shown below.

IR receiver circuit

The main components of the circuit are IR sensor TSOP 1738, microcontroller 89C51, current driver chip ULN2003A and all voltage regulator ICs (78XX series).

Connections:

24 VAC is rectified by diode bridge D1 and filtered through C1 and given to all the regulated ICs as input.
The output of 7805 is connected to 89C51 and TSOP and also to all the LEDs.
Output of 7812 (last one) is connected to common coil terminal and to ULN
The outputs of middle four regulated ICs are connected to DC motor through relay contacts.
Output of TSOP is connected with pin P3.3 (INT1) of microcontroller
All five leds are connected with port P0 as shown
Input of ULN is connected with Port 1 pins P1.0-P1.3, and outputs are connected with second terminal of relay coil.

Operation:

TSOP will detect the 38 KHz IR beam and gives the interrupt to 89C51.
89C51 will indicate the interrupt event on first (green) LED and energizes only one particular relay through ULN chip.
When any of the four relay get energized the motor will get supply from it and it will start running
As voltage is less it will run with less speed
So now its the function of microcontroller to receive signal from IR sensor, decrease the speed of train gradually in four steps and then stop it. And this is done by software embedded in to 89C51.

How the project works?

Initially when you switch on the supply 89C51 will switch all the relays RL1- RL4 one by one. So motor will get 9-12-15-18 V supply in steps and gradually increases its speed reaches max speed indicated by first red LED (P0.0).
Now if the signal is green then train will cross the pole with same pole
But if signal becomes red in between then IR sensor will detect IR beam and interrupts the 89C51
Getting first interrupt 89C51 will switch off RL4 and switch on RL3 so now motor will get 15 V supply and its speed will be decreased. That’s indicated by second red LED (P0.1)
Now 89C51 will wait for some time (2 to 3 sec) and train goes on with same speed. Again if still red signal is on 89C51 will be interrupted and this time it will switch on RL2. so now motor gets 12V supply and again its speed will be decreased indicated by third red LED (P0.2)
The same procedure repeats if 89C51 is interrupted third times. Now motor runs at min speed (9 V) indicated by fourth red LED (P0.3)
After same delay on receiving fourth interrupt all the relays will be switched off and motor is now stop so the train is also stopped. This is indicated by green LED.
After this interrupts will be disabled. So now when red signal becomes green driver must reset the controller to start the train again.

The complete pseudo code with necessary comments is as given

org 00h
mov r0,#01h ; initialize the counter to count no. of interrupts
sjmp over ; jump above the interrupt subroutine
org 0013h ; interrupt 1 subroutine location
mov ie,#00h ; disable interrupt first
clr p0.0 ; interrupt indication on green led
inc r0 ; increment counter
acall delay ; call 0.1 sec delay
setb p0.0 ; reset green led
cjne r0,#02h,nxt2 ;if counter is 2 then decrease speed be one step (15 V)
mov p0,#0fbh
mov p1,#04h ; give indication on second red led
sjmp out
nxt2: cjne r0,#03h,nxt3 ; if counter is 3 then decrease speed be two step (12 V)
mov p0,#0f7h
mov p1,#02h ; give indication on third red led
sjmp out
nxt3: cjne r0,#04h,nxt4 ; if counter is 4 then decrease speed be three step (9 V)
mov p0,#0efh
mov p1,#01h ; give indication on fourth red led
sjmp out
nxt4: cjne r0,#05h,out ; if counter is 5 then stop the train
mov p0,#0feh
mov p1,#00h ; indicate it by green led.
out: acall dely ; call 2 sec delay every time when speed is changed
mov ie,#84h ; enable interrupt again
reti ; return from interrupt
over:mov p1,#01h ; main program starts from here starts train with min speed
acall dely ; and gradually increase it to max in four step
mov p1,#02h ; with 2 sec delay in between
acall dely
mov p1,#04h
acall dely
mov p1,#08h
mov p0,#0fdh
mov ie,#84h ; enable the interrupt
here: sjmp here ; continue loop
delay:
mov r6,#64h ; 0.1 sec delay
lop2:mov r5,#0FAh
lop1:nop
nop
djnz r5,lop1
djnz r6,lop2
ret
dely:
mov r7,#15h ; 2 sec delay
lop5:mov r6,#64h
lop4:mov r5,#0FAh
lop3:nop
nop
djnz r5,lop3
djnz r6,lop4
djnz r7,lop5
ret
end

How-To: Device Switching Using PC’s Parallel Port

alman — Sat, 10 Oct 2009 19:51:27 +0000

Imagine the convenience, if we could control different devices at home/industry by using a single PC. Our project aims at the same and could be used to control the printer power, loads & other household electrical appliances. The circuit comprises decoder, inverter, latch & relay driver sections. To control these equipments we are using PC’s Parallel port. The program of controlling is written in C language. It is compiled using Turbo C compiler.

The project though a bit expensive, is very efficient in control of real world peripherals.

Contents:

INTRODUCTION
PARTS LIST
BLOCK DIAGRAM
COMPONENT DESCRIPTION
- Parallel Port
- IC 74LS154
- IC 74LS74
- 1C 74 LS05
- 1C ULN 2803
- Relay
CIRCUIT DESCRIPTION AND WORKING
SOFTWARE PROGRAM
CONCLUSION

INTRODUCTION:

The PC parallel port is an expensive yet a powerful platform for implementing projects dealing with the control of real-world peripherals. This port can be used to control the printer as also household and other electrical appliances. The computer program through the interface circuit controls the relays, which, in turn, switch the appliances on or off.

The parallel port has 12 outputs including 8 data lines and 4 control lines. The circuit described here can be used to control up to 255 electrical appliances using only eight data lines from the parallel port. Besides, the software program allows the users to know the current status of the loads.

PARTS LIST:

Semiconductors:
ICl, IC2, IC3 – 74LS154 l-of-16 decoder
IC4, IC5, IC6 – 74LSO5 inverter
IC7-ICI4 – 74LS74 D-type flip/flop
ICI5, IC16 – ULN2803 octal Darlington array driver
Misc.
Power supply – 5V regulated DC, 12VregulatedDC
Relay – 12V,200-ohm, lC/O SPDT

BLOCK DIAGRAM:

The block diagram in Fig. 1 depicts the main components of the switching system for 255 electrical loads using PC. The control command to switch on/off the appliances is given through the keyboard. The software program scans the input and as per the input command, the data is available at the parallel port.

Fig 1. Block Diagram

Out of eight bits, first four bits (D0 through D3) are data signal bits and the remaining four bits (D4 through D7) are used as control signals. Control signals are given to decoder 1. The output of decoder 1 is given to Enable pins of decoders 2 and 3. Data signals are given to both decoders 2 and 3. The outputs of decoders 2 and 3 are inverted and fed to a D-type flip/flop that is used to latch the data. The latched data output is given to relay driver ICs ULN2803. The relay drivers drive the relays for switching the appliances.

COMPONENT DESCRIPTION:

1. THE PARALLEL PORT:

The parallel port or line printer terminal (LPT) port is a 25-pin D-type female connector available at the back of your PC. A basic IBM PC usually comes with one or two LPT ports. The original parallel port, called standard parallel port (SPP), is a bundle of three ports (or registers), namely, data port, status port, and control port. Pins 2 through 9 form the 8-bit data port. This port is purely a write-only port. This means it can be used only to output some data through it. Pins I, 14, 16, and 17 form the control port, which is capable of reading/writing. Pins 10 through 13 and pin 15 together form the status port. The status port is a read-only port. The details of 25-pin parallel port are given in Table 1.

TABLE 1: Parallel Port Pin Details

The base address of the first parallel port (LPT1) is 0378 in hexadecimal (hex) notation (or 888 in decimal notation). The base address of the second parallel port (LPT2) is 0278 in hex. In this project, we’ve used only LPT1.

2. DM74LS154 : 4-LINE TO 16-LINE DECODER / DE-MULTIPLEXER:

Each of these 4-line-to-16-line decoders utilizes TTL circuitry to decode four binary-coded inputs into one of six-teen mutually exclusive outputs when both the strobe inputs, GI and G2, are LOW. The de-multiplexing function is performed by using the 4 input lines to address the out-put line, passing data from one of the strobe inputs with the other strobe input LOW. When either strobe input is HIGH, all outputs are HIGH. These de-multiplexers are ideally suited for implementing high-performance memory decoders.
All inputs are buffered and input clamping diodes are provided to minimize transmission line effects and thereby simplify system design.

3. 74LS74 : DUAL D-TYPE POSITIVE-EDGE-TRIGGERED FLIP-FLOPS:

These devices contain two independent D-type positive-edge triggered flip-flops. A low level at the preset or clear inputs sets or resets the outputs regardless of the levels of the other inputs. When preset and clear are inactive (high), data at the D input meeting the setup time requirements are transferred to the outputs on the positive-going edge of the clock pulse. Clock triggering occurs at a voltage level and is not directly related to the rise time of the clock pulse. Following the hold time interval, data at the D input may be changed without affecting the levels at the outputs.

4. HEX INVERTER:

It is used for inversion of input signal. Since outputs from the de-multiplexers are active low, we invert them. This IC has 6 not-gates and hence called a hex-inverter.

5. ULN-2803 : OCTAL PERIPHERAL DRIVER ARRAYS:

The eight NPN Darlington connected transistors in this family of arrays are ideally suited for interfacing between low logic level digital circuitry (such as TTL, CMOS or PMOS/NMOS) and the higher current/voltage requirements of lamps, relays, printer hammers or other similar loads for a broad range of computer, industrial, and consumer applications. All devices feature open-collector outputs and freewheeling clamp diodes for transient suppression. The ULN2803 is designed to be compatible with standard TTL families while the ULN2804 is optimized for 6 to 15volt high-level CMOS or PMOS.

6. RELAYS:

The relay is a device by means of which an electrical circuit can be controlled (opened or closed) by sensing a change in the circuit in which it is connected. The relays can be either electromagnetic or electronic. In this circuit the electromagnetic relay is used to connect or disconnect the supply to the appliance to be controlled. It works on the principle of electromagnetic attraction and electromagnetic induction. These relays can be actuated by AC or DC quantities. In these relays there are one or more coils, movable elements, contact systems etc.

CIRCUIT DESCRIPTION AND WORKING:

The circuit comprises decoder, inverter, latch circuit, and relay driver sections. The circuit, excluding relay drivers and relays, is powered by a 5V DC regulated supply. Relay drivers and relays are driven by a 12V DC regulated supply. Each relay is rated 12V,200-ohm.

The circuit for switching on/off 6 loads is shown in Fig. 2. For more than 6 loads, you can add more ICs in a similar way as shown in this circuit. IC 74LSI54 is a 24-pin, 4-to-16 line decoder IC. This IC is designed to accept four inputs and provide 16outputs. Input addresses Al through A4 to pins 20 through 23 of IC1 and IC2 (IC 74LSI54) each are given from the data lines of the computer parallel port.

In this circuit, only pins 2 through 9 of the parallel port are used, where data lines D0 through D3 form the 4-bit data input and D4 through D7 are address-select or control lines for the circuit. Pins 18 through 25 are shorted to ground. Data lines D0 through D3 are the input addresses for IC2, and data linesD4 through D7 are the input addresses for IC1.

When Enable pins EI and E2 (active low) are high, all the outputs go high irrespective of the address inputs (AI through A4). Enable pins EI and E2 of ICI are grounded and its output pins YO through YI5 are connected to Enable pins of the respective decoder ICs.

Initially all the data inputs (D0 through D7) are low. Thus, except Y0,all the outputs of ICI and IC2 are high. The output Y0 of IC2 is not used, for the reason that when all the input data is low, none of the outputs of IC 74LSI54 is used for switching the loads. Suppose, out of eight input data lines, D0 is high. So, except Y1, all the outputs of IC2 will be high. YI is then inverted using IC4 (IC 74LS05). The output of IC4 at pin 2 is given to pin 3 of IC7 (lC 74LS74). IC 74LS74 is a dual D-type flip-flop used for latching the data.

With an active rising edge of the clock pulse (CP-1 or CP-2), the data input will be locked in IC7 through IC14 until the next rising edge of the input clock pulse. The outputs of ICs 74LS74 are given to relay driver ICs ULN2803 (lC-15 and IC-16), which, in turn, drive the relays. The relays are used to switch on/off the appliances.

Fig 2. Circuit diagram of the project

SOFTWARE :

The program to control the appliances is written in C. it is compiled using Turbo C compiler. The flow chart of the program is as follows

Fig-3: Flow chart for Implementation of Program

Fig-4: Flow charts of the functions Used

On running the program SRC_CODE.C the menu appears as shown below, asking for the operation to be done.

The very first option shows the list of the loads that could be controlled using this software along with their codes.

The outstanding part of this software is activating of required PROFILES at once so that the burden of controlling of individual devices is eliminated.

The activation of night profile is as shown below. We can even set the user defined profiles.

As a basic requirement the control over individual devices is also provided. If the user by mistake tries to switch ON the device which is already ON, the software detects it & the corresponding message is displayed.

The software also allows the user to know the current status of the loads.

SOURCE CODE:

/* PROGRAM TO CONTROL MULTIPLE DEVICES USING PC’S PARALLEL PORT */

#include
#include
#include
#include
#include

FILE *status;
int ch;
char *dev_list[]={”idle”,”TUBELIGHT”,”FAN”,”NIGHTLAMP”,”TELEVISION”, ”AIRCOOLER”,”REFRIGERATOR”,”DVD_PLAYER”,”end” };
int day[]={0,2,4,6,0,1,3,5,7,0};
int night[]={0,1,2,3,5,6,7,0,4,0};
int out[]={0,3,0,1,2,4,5,6,7,0};
int reset[]={0,0,1,2,3,4,5,6,7,0};
int device[256];
int port=0×378;

void activate(int *ptr);
void switch_load(int);

main()
{
int disp_menu();
void disp_load();
void profiles();
void switching();
void load_status();
void exit_code();
int welcome();
int choice;
int hour;
status_file();
for(;;)
{
clrscr();
hour=welcome();
choice=disp_menu();
switch(choice)
{
case 1: disp_load();
printf(”’n’n’n Press any key to continue….”);
getch();
break;
case 2: profiles();
break;
case 3: switching();
break;
case 4: load_status();
break;
case 5: exit_code(hour);
default: printf(”’n’n INVALID CHOICE”);
printf(”’n’n’n’n’n PRESS ANY KEY TO RETURN TO MAIN MENU…..”);
getch();
}
}
}

status_file()
{
int i=0;
status=fopen(”status.txt”,”r”);
if(status==NULL)
{
puts(”Unable to open device status file”);
exit(1);
}
while(1)
{
ch=fgetc(status);
if(i>=256)
break;
else
device[i]=ch;
i++;
}
fclose(status);
return(0);
}

welcome()
{
struct time t;
struct date d;
clrscr();
printf(”’n’n’t’t’t $$$ POWER CONTROL USING PC $$$’n’n’n”);
gettime(&t);
getdate(&d);
printf(”’n’n TIME: %2d:%2d”,t.ti_hour,t.ti_min);
printf(”’n’n DATE: %2d/0%d/%2d”,d.da_day,d.da_mon,d.da_year);
if(t.ti_hour>=0×5&&t.ti_hour<0xb)
printf(”’n’n GOOD MORNING….’n”);
if(t.ti_hour>=0xb&&t.ti_hour<0×11)
printf(”’n’n GOOD AFTERNOON….”);
if(t.ti_hour>=0×11&&t.ti_hour<0×16)
printf(”’n’n GOOD EVENING….”);
return(t.ti_hour);
}

int disp_menu()
{
int choice;
printf(”’n 1.LIST OF LOADS & THEIR CODES”);
printf(”’n 2.STANDARD PROFILES(DAY/NIGHT)”);
printf(”’n 3.SWITCHING”);
printf(”’n 4.LOAD’S STATUS”);
printf(”’n 5.EXIT’n”);
printf(”’t’t’t’t ENTER YOUR CHOICE:”);
scanf(”%d”,&choice);
return(choice);
}

void disp_load()
{
int i;
clrscr();
printf(”’n THE LIST OF LOADS WHICH CAN BE CONTROLLED ARE:’n’n”);
for(i=1;strcmpi(&dev_list[i][0],”end”);i++)
printf(”’n’t %2d.%s”,i,dev_list[i]);
return;
}

void profiles()
{
char p;
for(;;)
{
clrscr();
printf(”’n STANDARD PROFILES:’n”);
printf(”’n’n’t’t 1.DAY MODE”);
printf(”’n’t’t 2.NIGHT MODE”);
printf(”’n’t’t 3.OUT OF STATION”);
printf(”’n’t’t 4.RESET”);
printf(”’n’t’t 5.EXIT”);
printf(”’n’n’n’n ENTER YOUR CHOICE: “);
p=getchar();
switch(p)
{
case ‘d’:
case ‘D’:
case ‘1′: activate(day);
return;
case ‘n’:
case ‘N’:
case ‘2′: activate(night);
return;
case ‘o’:
case ‘O’:
case ‘3′: activate(out);
return;
case ‘r’:
case ‘R’:
case ‘4′: activate(reset);
return;
case ‘e’:
case ‘E’:
case ‘5′: return;
}
}
}

void activate(int *ptr)
{
int i;
char c;
printf(”’n’nTHE FOLLOWING DEVICES WILL BE SWITCHED ON…..’n”);
for(i=1;ptr[i]!=0;i++)
printf(”’n%d.%s”,ptr[i],dev_list[ptr[i]]);
printf(”’n’nTHE FOLLOWING DEVICES WILL BE SWITCHED OFF…..’n”);
for(i++;ptr[i]!=0;i++)
printf(”’n%d.%s”,ptr[i],dev_list[ptr[i]]);
printf(”’n’n DO YOU WANT TO ACTIVATE THIS PROFILE….(y/n):”);
c=getch();
printf(”%c”,c);
getch();
if(c==’y’||c==’Y’)
{
for(i=1;ptr[i]!=0;i++)
if(device[ptr[i]]==0)
switch_load(ptr[i]);
for(i++;ptr[i]!=0;i++)
if(device[ptr[i]]==1)
switch_load(ptr[i]);
}
}

void switching()
{
int i,on_off;
disp_load();
printf(”’n’n’n’nEnter the code of the device to be switched:”);
scanf(”%d”,&i);
printf(”OPTIONS:”);
printf(”’t 0–OFF’t 1–ON’n”);
printf(”’n ENTER YOUR CHOICE:”);
reenter: scanf(”%d”,&on_off) ;
if(on_off==1)
{
if(device[i]==1)
{
printf(”’nThe Device is already ON”);
getch();
}
else
switch_load(i);
}
else if(on_off==0)
{
if(device[i]==0)
{
printf(”’nThe Device is already OFF…”);
getch();
}
else
switch_load(i);
}
else
{
printf(”Invalid option’n Please Re-enter”);
goto reenter;
}
}

void load_status()
{
int i;
clrscr();
printf(”’n’n THE FOLLOWING DEVICES ARE ON:’n”);
for(i=1;strcmpi(&dev_list[i][0],”end”);i++)
if(device[i]==1)
printf(”’n%d.%s”,i,dev_list[i]);
printf(”’n’nTHE FOLLOWING DEVICES ARE OFF:’n”);
for(i=1;strcmpi(&dev_list[i][0],”end”);i++)
if(device[i]==0)
printf(”’n%d.%s”,i,dev_list[i]);
printf(”’n’n’n’nPress any key to continue……”);
getch();
}

void switch_load(int adrr)
{
if(device[adrr]==0)
{
device[adrr]=1;
outportb(port,adrr);
delay(50);
outportb(port,0×00);
}
else
{
evice[adrr]=0;
outportb(port,adrr);
delay(50);
outportb(port,0×00);
}
}

void exit_code(int hour)
{
clrscr();
printf(”’t’t’t THANK YOU FOR USING THIS SOFTWARE ’n”);
if(hour>=0×13||hour<=0×4)
printf(”’n’n GOOD NIGHT….’n”);
file_update();
printf(”’n’n’n’n’n’n’n Press any key to EXIT……”);
getch();
exit(0);
}

file_update()
{
int i=0;
status=fopen(”status.txt”,”w+”);
if(status==NULL)
{
puts(”Unable to open device status file”);
exit(1);
}
while(1)
{
ch=device[i];
if(i>=256)
break;
else
fputc(ch,status);
i++;
}
fclose(status);
return 0;
}

CONCLUSION:
This project, can be effectively and conveniently utilized for the control of different appliances. As this project could be extended to control about 255 devices, this could be used for computerization of an office, home, or a firm. Though it is quiet costlier, the circuit is simple and the working mechanism could be easily understood. An added advantage of this project is that we are able to know the status of the device to be controlled. The program to control the appliances is written in C language which is more user friendly and easy to understand than other programming languages.
Disadvantages / Improvements:-
If at all a new device has to be added to the hardware the software doesn’t support this to achieve which the source code has to be changed manually.
The status of all the devices that are switched are maintained in a database which may not coincide with actual status of the devices as we are not reading the status directly from the HARDWARE.

This is the Project By
1. Anand Kumar. N. Ilkal
2. Anil Kumar Desai
3. Gara Naveen
4. Umesh. N. Sajjan

How-To: Solve Sudoku using C++

alman — Sat, 10 Oct 2009 19:36:30 +0000

You have seen it in the news papers, you have seen it in the magazines or in the web sites, you might have sat hours ‘n hours to solve it. Yes, it is the king of all number puzzles, it is “SUDOKU”.

We bring to you the ultimate solution for all your struggles, The SUDOKU Solver.

As you know, now a days mathematical puzzle-SUDOKU is in boom all over the world. Sudoku is a 9X9 matrix with nine 3×3 sub-matrices, that we need to fill by entering the numbers from 1 through 9, without the repetition of the a number in the rows, columns or in the sub matrices.

Figure: 1- Sudoku Problem

We can get the Sudoku puzzle in ease by different means, as discussed. You might have struggled a lot to solve the same. To be true, even me too. Here I developed a fast and robust package, that solves the puzzles, that are not easy to solve by hands. It will solve the Sudoku entered in fraction of a milli-second and will display the solved result.

Figure: 2 – Sudoku Result

Download the executable at the end of this post.

When the code executes, a blank Sudoku will be displayed with 9×9 red boxes. The user is needed to enter the numbers corresponding to the source puzzle (Figure 1). To enter this, user should use the arrow keys to cruse to the required box. The selected box will be highlighted with a blue boundary. You have to enter the number through the keyboard. Once you have done entering all the numbers in the puzzle just hit the ‘Enter’ key on the keyboard till you get the solved result (Figure 2). If the Sudoku cannot be solved by this program a message will be displayed telling that the given puzzle cannot be solved.

Attached Files:

sudoku.zip (30 KB)

How-To: Build Digital IC Tester

alman — Sat, 10 Oct 2009 19:27:17 +0000

An Integrated Circuit tester (IC tester) is used to test Integrated Circuits (ICs). We can easily test any digital IC using this kind of an IC tester. For testing an IC, we need to use different hardware circuits for different ICs; like we need a particular kind of tester for testing a logic gate and another for testing flip flops or shift registers which involves more complication and time involved will also be more. So here’s an IC tester to overcome this problem.Unlike other IC testers, this is more reliable and easier since we don’t need to rig up different kind of circuits for different kind of ICs, each time we need to test them.

Unlike the IC testers available in the market today which are usually expensive, this IC tester is affordable and user-friendly. This IC tester is constructed using 8951 microcontroller along with a keyboard and a display unit. It can test digital ICs having a maximum of 24 pins. Since it is programmable, any number of ICs can be tested within the constraint of the memory available. This IC tester can be used to test a wide variety of ICs which includes simple logic gates and also sequential and combinational ICs like flip-flops, counters, shift registers etc. It is portable and easy to use.

The block diagram of the programmable digital IC tester is as shown in below. It consists of two 8951 microcontroller ICs, a 24-pin IC socket, a keyboard unit, a display unit and indicators.

To test a particular digital IC, one needs to insert the IC into the IC socket and enter the IC number using the keyboard and then press the “ENTER” key. The IC number gets displayed in the 7-segment display unit.

Four LEDs are provided as indicators. If the IC being tested is a logic gate, then each of the 4 indicator LEDs correspond to the 4 gates of the IC. In any other case wherein the inserted IC is not a logic gate, all the 4 LEDs work as a single indicator.

Digital IC Tester

Block diagram of Programmable Digital IC Tester:

Block diagram

Circuit diagram of programmable digital IC tester is shown below.

Circuit diagram

The programmable digital IC tester consists of 2 8951 microcontroller. One is called master and the other slave. The master controls the slave and the working of the display and keyboard units. The slave IC is used for testing the IC inserted into the IC socket. Out of the four ports available in the 8951, three ports – port 0, port 1(Not all pins), port 2 are connected to the 24 pins of the IC socket. Port 3 is used for parallel communication between the slave and the master.

The keyboard and display units are interfaced with the master IC. Four indicators are also connected to the master IC. When we feed the number of the IC being tested, the number gets stored in the memory of the master IC and also gets displayed in the in the 7-segment display. The display unit is connected to the lower pins of port 0 of the master IC. The keyboard is connected to port 1 and the four indicators are connected to the port 1 of Slave IC.

Parallel communication is used between the master and the slave. There are four data lines and three control lines for transfer and control of data between the master and the slave. Port 3 of the slave IC and port 2 of the master IC are used for parallel communication.

The process of parallel communication is as follows:

The slave sends a ready bit to the master IC when it is ready to receive data.
If the slave is ready, the master places the data on the data lines.
A control bit gets set as soon the master transmits the data.
The slave checks whether the bit is set, and then receives the data.
Another control bit gets set as soon as the slave receives the data.
A third control bit gets set whenever the slave is ready to accept another set of data.

As soon as the slave gets the IC number, it compares the IC number with the stored list and then goes to the corresponding service routine. The service routine checks the particular IC. Depending to the IC, it assigns some ports as input ports and some as output ports. It gives the corresponding inputs and checks for the output according to the IC logic. If the output is according to the IC logic, the slave sends the data to the master IC. If the IC is a logic gate, then the data will consist of 4 bits, where each bit corresponds to each gate of the IC. In case the IC is not a logic gate, the data consists of a single bit, which may be a ‘0’ or a ‘1’. Corresponding to these four bits, the master sets or resets the lower port of P3, which is connected to the indicators. Four LEDs are interfaced to the master IC as indicators. If the IC being tested is a logic gate, then each of the 4 indicator LEDs correspond to the 4 gates of the IC. In any other case wherein the inserted IC is not a logic gate, all the 4 LEDs work as a single indicator.

Using this IC tester, any digital IC can be tested provided its program is written. For a particular IC, the corresponding program must be written in the slave. The total number of ICs that can be tested using this IC tester, depends on the memory available in the slave. The 8951 microcontroller consists of a 4k ROM, using which around 150 ICs can be tested. To test more number of ICs, a microcontroller with an 8k ROM can be used.

The keyboard is provided with a ‘RESET’ button, which when pressed resets both the microcontrollers and the 4 shift registers. The shift registers require a low pulse to get reset, whereas the microcontrollers require a high pulse to get reset. To synchronize this, a NOT gate is used.

Display Unit:

The display unit is used to display the IC number. This unit consists of five common anode 7-segment displays, five 7447 ICs(BCD to 7-segment converter) and four 74194 ICs(4-bit bidirectional universal shift register).

Here, the shift registers are used in parallel load (parallel in parallel out) mode. These shift registers are used to shift the digits of the IC number. When the first digit is pressed, the master recognizes it and places it in the lower pins of port 0. These four bits are connected to the input of the first shift register and also to the input of the first 7447 IC. The 7447 is a BCD to 7-segment converter, which converts the four input bits (BCD) to their corresponding 7-segment codes.

The outputs of the 7447 are connected to the 7-segment displays. Hence the first digit gets displayed in the right-most 7-segment display. As the next number is typed in, the master gives a clock pulse to the shift registers to shift the data. Then the master places the second digit on the lower pins of port 0. Hence the new digit gets displayed in the right-most 7-segment display and the previous digit gets shifted to the left.

S0 and S1 of the 74194 IC are connected to +Vcc, to work in parallel mode. P3.4 of the master is connected to the clock pins of all the shift registers. These shift registers require a low to high clock pulse. The ‘RESET’ button provided in the keyboard resets all the shift registers. The common pins of the 7-segment display are connected to +Vcc.

The entire display section is shown in the figure below.

Circuit diagram of Display section

Keyboard section:

The keyboard section is as shown in the figure below. The keyboard is designed as a matrix and is interfaced to port 1 of the master IC. Here P1.0, P1.1, P1.2 are configured as input ports, and P1.3, P1.4, P1.5, P1.6 are configured as output ports. The keyboard consists of 10 digits as well as an ‘ENTER’ button.

Circuit diagram of Keyboard section

Software program for master IC:

setb p2.7
mov r0,#30h
mov p1,#0ffh
mov r7,#01
start: mov p0,#0 ;Clear first digit
wait: setb p1.3 ;Keyboard interfacing
setb p1.4 ;Enable all rows
setb p1.5
setb p1.6
jb p1.0,key ;Check whether key is pressed
jb p1.1,key
jb p1.2,key
jmp wait ;If not, check again

key: mov r2,#0a0h
d: djnz r2,d
mov r1,#01 ;Pressed digit
mov r2,#01
nextrow:cjne r2,#01,nextr1
setb p1.6 ;Enable first row
clr p1.5 ;Disable other rows
clr p1.4
clr p1.3
jmp over
nextr1: cjne r2,#02,nextr2
setb p1.5 ;Enable second row
clr p1.6 ;Disable other rows
clr p1.4
clr p1.3
jmp over
nextr2: cjne r2,#03,nextr3
setb p1.4 ;Enable third row
clr p1.5 ;Disable other rows
clr p1.6
clr p1.3
jmp over
nextr3: setb p1.3
clr p1.5 ;Enable fourth row
clr p1.4 ;Disable other rows
clr p1.6
over: jb p1.0,col1 ;If key is pressed in particular row, check
jb p1.1,col2 ; for corresponding column
jb p1.2,col3
mov a,#03
add a,r1
mov r1,a
inc r2
jmp nextrow

col1: jnb p1.0,over
jmp done
col2: jnb p1.1,over
inc r1
jmp done
col3: jnb p1.2,over
mov a,#02
add a,r1
mov r1,a
done: mov a,r1
cjne a,#0bh,enter
mov r1,#0
jmp down
enter: mov a,r1
cjne a,#0ch,down
jmp out
down: mov @r0,r1
inc r0
mov a,#01
xrl a,r7
jz noshift
clr p3.4
mov r2,#0ffh
here: djnz r2,here
setb p3.4

noshift: mov r7,#00
mov p0,r1
wait1: jb p1.0,wait1
jb p1.1,wait1
jb p1.2,wait1
mov r2,#0ffh
delay2: djnz r2,delay2
wait2: jmp wait

out: cjne a,#0ch,wait2
clr p2.4
mov r2,#0ffh
here1: djnz r2,here1
setb p2.4
mov a,#0
mov p0,a
out1: jb p1.0,out1
jb p1.1,out1
jb p1.2,out1
mov a,r0
subb a,#02
mov r0,a
mov a,@r0
swap a
mov r5,a
inc r0
mov a,@r0
add a,r5
mov r5,a
cjne r5,#0,nor
mov a,#1
jmp x
nor: cjne r5,#02,and
mov a,#2
jmp x
and: cjne r5,#08,or
mov a,#3
jmp x
or: cjne r5,#32h,xor
mov a,#4
jmp x
xor: cjne r5,#86h,else
mov a,#5
jmp x
else: mov a,#0fh
x: mov p2,#00
jnb a.0,nextb1
setb p2.0

nextb1: jnb a.1,nextb2
setb p2.1
nextb2: jnb a.2,nextb3
setb p2.2
nextb3: jnb a.3,ove
setb p2.3
ove: clr p2.7

end: jmp end

Software program for slave IC:

mov p0,#0
mov p2,#0
mov p1,#0
mov r0,#0ffh
del: djnz r0,del
setb p3.7
wait:jb p3.7,wait
mov a,#0
setb p3.0
setb p3.1
setb p3.2
setb p3.3
jnb p3.0,nextb1
setb a.0
nextb1: jnb p3.1,nextb2
setb a.1
nextb2: jnb p3.2,nextb3
setb a.2
nextb3: jnb p3.3,over
setb a.3

over:cjne a,#1,next2 ;NAND
call gateic
mov a,r3
rl a
mov r2,#07h
xrl a,r2
jnz checkg12
setb p1.2

checkg12: mov a,r4
rl a
mov r2,#07h
xrl a,r2
jnz checkg13
setb p1.3

checkg13: mov a,r5
rl a
mov r2,#07h
xrl a,r2
jnz checkg14
setb p1.4

checkg14: mov a,r5
rl a
mov r2,#07h
xrl a,r2
jnz end2
setb p1.5
jmp end2

next2: cjne a,#2,next3 ;NOR
call gateic
mov a,r3
rl a
mov r2,#01h
xrl a,r2
jnz checkg22
setb p1.2

checkg22: mov a,r4
rl a
mov r2,#01h
xrl a,r2
jnz checkg23
setb p1.3

checkg23: mov a,r5
rl a
mov r2,#01h
xrl a,r2
jnz checkg24
setb p1.4

checkg24: mov a,r5
rl a
mov r2,#01h
xrl a,r2
jnz end1
setb p1.5
end2: jmp end1

next3: cjne a,#3,next4 ;AND
call gateic
mov a,r3
rl a
mov r2,#08h
xrl a,r2
jnz checkg32
setb p1.2

checkg32: mov a,r4
rl a
mov r2,#08h
xrl a,r2
jnz checkg33
setb p1.3

checkg33: mov a,r5
rl a
mov r2,#08h
xrl a,r2
jnz checkg34
setb p1.4

checkg34: mov a,r5
rl a
mov r2,#08h
xrl a,r2
jnz end1
setb p1.5
jmp end1

next4: cjne a,#4,next5 ;OR
call gateic
mov a,r3
rl a
mov r2,#0Eh
xrl a,r2
jnz checkg2
setb p1.2

checkg2: mov a,r4
rl a
mov r2,#0Eh
xrl a,r2
jnz checkg3
setb p1.3

checkg3: mov a,r5
rl a
mov r2,#0Eh
xrl a,r2
jnz checkg4
setb p1.4

checkg4: mov a,r5
rl a
mov r2,#0Eh
xrl a,r2
jnz end3
setb p1.5

end1: jmp end3

next5: cjne a,#5,end2 ;XOR
call gateic
mov a,r3
rl a
mov r2,#06h
xrl a,r2
jnz checkg52
setb p1.2

checkg52: mov a,r4
rl a
mov r2,#06h
xrl a,r2
jnz checkg53
setb p1.3

checkg53: mov a,r5
rl a
mov r2,#06h
xrl a,r2
jnz checkg54
setb p1.4

checkg54: mov a,r5
rl a
mov r2,#06h
xrl a,r2
jnz end
setb p1.5
end3: jmp end

gateic: mov r0,#25h
mov a,#24h
mov @r0,a
inc r0
mov a,#2Dh
mov @r0,a
inc r0
mov a,#36h
mov @r0,a
inc r0
mov a,#3Fh
mov @r0,a
mov r1,#30h
mov a,#92h
mov @r1,a
inc r1
mov a,#B6h
mov @r1,a
inc r1
mov a,#DAh
mov @r1,a
inc r1
mov a,#FEh
mov @r1,a
mov r0,#25h
mov r1,#30h
mov r3,#0
mov r4,#0
mov r5,#0
mov r6,#0
mov r7,#4

nextcnd:mov a,@r0
inc r0
mov p0,a
mov a,r3
jnb p0.2,g2
setb a.3
g2: rr a
mov r3,a
mov a,r4
jnb p0.5,g3
setb a.3
g3: rr a
mov r4,a
mov a,@r1
inc r1
mov p2,a
mov a,r5
jnb p2.1,g4
setb a.3
g4: rr a
mov r5,a
mov a,r6
jnb p2.4,overcnd
setb a.3
overcnd:rr a
mov r6,a
djnz r7,nextcnd
ret

end: clr p3.6

stop: jmp stop

If anybody get this project success full then leave the comment and share your joy

How-To: Build Vehicle Monitoring and Security System

alman — Sat, 10 Oct 2009 19:11:46 +0000

ABSTRACT:In this modern, fast moving and insecure world, it is become a basic necessity to be aware of one’s safety. Maximum risks occur in situations wherein an employee travels for money transactions. Also the Company to which he belongs should be aware if there is some problem. What if the person traveling can be tracked and also secured in the case of an emergency?! Fantastic, isn’t it? Of course it is and here’s a system that functions as a tracking and a security system. It’s the VMSS. This system can deal with both pace and security.

The VMSS (Vehicle Monitoring and Security System) is a GPS based vehicle tracking system that is used for security applications as well. The project uses two main underlying concepts. These are GPS (Global Positioning System) and GSM (Global System for Mobile Communication). The main application of this system in this context is tracking the vehicle to which the GPS is connected, giving the information about its position whenever required and for the security of each person travelling by the vehicle. This is done with the help of the GPS satellite and the GPS module attached to the vehicle which needs to be tracked. The GPS antenna present in the GPS module receives the information from the GPS satellite in NMEA (National Marine Electronics Association) format and thus it reveals the position information. This information got from the GPS antenna has to be sent to the Base station wherein it is decoded. For this we use GSM module which has an antenna too. Thus we have at the Base station; the complete data about the vehicle.

Along with tracking the vehicle, the system is used for security applications as well. Each passenger/employee will have an ID of their own and will be using a remote containing key for Entry, Exit and Panic. The Panic button is used by the driver or the passenger so as to alert the concerned of emergency conditions. On pressing this button, an alarm will be activated which will help the passenger/employee in emergencies and keep them secure throughout the journey. The vehicle can also be immobilized remotely.

INTRODUCTION:

Of all the applications of GPS, Vehicle tracking and navigational systems have brought this technology to the day-to-day life of the common man. Today GPS fitted cars, ambulances, fleets and police vehicles are common sights on the roads of developed countries. Known by many names such as Automatic Vehicle Locating System (AVLS), Vehicle Tracking and Information System (VTIS), Mobile Asset Management System (MAMS), these systems offer an effective tool for improving the operational efficiency and utilization of the vehicles.

GPS is used in the vehicles for both tracking and navigation. Tracking systems enable a base station to keep track of the vehicles without the intervention of the driver whereas navigation system helps the driver to reach the destination. Whether navigation system or tracking system, the architecture is more or less similar. The navigation system will have convenient, usually a graphic display for the driver which is not needed for the tracking system. Vehicle tracking systems combine a number of well-developed technologies.

To design the VMSS system, we combined the GPS’s ability to pin-point location along with the ability of the Global System for Mobile Communications (GSM) to communicate with a control center in a wireless fashion. The system includes GPS-GSM modules and a base station called the control center.

Let us briefly explain how VMSS works. In order to monitor the vehicle, it is equipped with a GPS-GSM VMSS system. It receives GPS signals from satellites, computes the location information, and then sends it to the control center. With the vehicle location information, the control center displays all of the vehicle positions on an electronic map in order to easily monitor and control their routes. Besides tracking control, the control center can also maintain wireless communication with the GPS units to provide other services such as alarms, status control, and system updates.

The design takes into consideration important factors regarding both position and data communication. Thus, the project integrates location determination (GPS) and cellular (GSM) – two distinct and powerful technologies in a single system.

VMSS is based on a PIC microcontroller-based system equipped with a GPS receiver and a GSM Module operating in the 900 MHz band. We housed the parts in one small plastic unit, which was then mounted on the vehicle and connected to GPS and GSM antennas. The position, identity, heading, and speed are transmitted either automatically at user-defined time intervals or when a certain event occurs with an assigned message (e.g.; accident, alert, or leaving/entering an admissible geographical area).

The GPS Module outputs the vehicle location information such as longitude, latitude, direction, and Greenwich Time every five minutes. The GSM wireless communications function is based on a GSM network established in a valid region and with a valid service provider. Via the SMS provided by the GSM network, the location information and the status of the GPS-GSM VMSS are sent to the control center. Meanwhile, the VMSS receives the control information from the control center via the same SMS. Next, the GPS-GSM VMSS sends the information stored in the microcontroller via an RS-232 interface.

There are two ways to use the VMSS’ alarm function, which can be signified by either a buzzer or presented on LCD. The first way is to receive the command from the control center; second way is to manually send the alarm information to the control center with the push of a button.

The base station consists of landline modem(s) and GIS workstation. The information about the vehicle is received at a base station and is then displayed on a PC based map. Vehicle information can be viewed on electronic maps via the Internet or specialized software. Geographic Information Systems (GIS) provides a current, spatial, visual representation of transit operations. It is a special type of computerized database management system in which geographic databases are related to one via a common set of location coordinates.

STAGES OF VMSS

STAGE 1:

Driver starts his trip from the transport office.
VMSS transmits the Driver I.D and the Vehicle I.D along with the position of the vehicle to the base station.

STAGE 2:

Taxi picks up the employee/passenger from their residence.
VMSS transmits the Passenger I.D and the Vehicle I.D along with the position of the vehicle to the base station. Therefore base station will be able to keep a track of the vehicle and thus the employee/passenger.

STAGE 3:

Taxi drops the employee/passenger to the workplace.
VMSS transmits the Passenger I.D and the Vehicle I.D along with the position of the vehicle to the base station.

STAGE 4:

Taxi picks the employee/passenger from the workplace.
VMSS transmits the Passenger I.D and the Vehicle I.D along with the position of the vehicle to the base station. Therefore this enables the base station to estimate the time if required and also keep a track of the vehicle, passenger and the driver.

STAGE 5:

Taxi drops the employee/passenger to their residence.
VMSS transmits the Passenger I.D and the vehicle I.D along with the position of the vehicle to the base station and makes sure that the job is 100% complete.

HI-TECH ‘C’ AND MPLAB – AN OVERVIEW

HI-TECH software makes industrial-strength development tools and C compilers that help software developers write compact, efficient embedded processor code. HI-TECH PICC-18™ is a powerful C compiler for the Microchip PICmicro® PIC18 family of microcontrollers. HI-TECH PICC-18 delivers unrivalled code density combined with excellent reliability. Tightly tuned to the PIC18 architecture, it allows firmware development in a fraction of the time, but with no greater use of RAM or ROM, required for conventional assembly language programming. It is also a USER FRIENDLY language.

HI-TECH PICC-18™ Compiler Features:

ANSI C – full featured and portable
Efficient – equals or betters hand-written assembler code
Reliable – mature, field-proven technology
Modular – includes full object code linker and library manager
Cost-effective – productivity gains rapidly repay purchase cost
Compatible – integrates into the MPLAB® IDE, MPLAB ICE2000 and
4000, ICD2 and most 3rd-party development tools
Library source – for standard libraries and sample code for various
peripherals and applications
Complete – includes macro assembler, preprocessor and one-step driver

MPLAB IDE – AN OVERVIEW

MPLAB is a Windows program package that makes writing and developing a program easier. It could best be described as developing environment for a standard program language that is intended for programming a PC. MPLAB allows you to write, debug, and optimize the PICmicro MCU applications for firmware product designs. Integrated Development Environment (IDE) is an application that has multiple functions for software development. MPLAB IDE an executable program that integrates a compiler, an assembler, a project manager, an editor, a debugger, simulator, and an assortment of other tools within one Windows application. A user developing an application should be able to write code, compile, debug and test and application without leaving the MPLAB IDE desktop. MPLAB IDE runs as a 32-bit application on MS Windows, is easy to use and includes a host of free software components for fast application development and super- charged debugging.

MPLAB ICD 2 – AN OVERVIEW
Traditionally, embedded systems engineers use in-circuit emulators (ICE) to develop and debug their designs and then programmers to transfer the code to the devices. The in-circuit debugging logic, when implemented, is part of the actual microcontroller silicon and provides a low-cost alternative to a more expensive ICE. In-circuit debugging offers these benefits:

Low cost
Minimum of extra hardware
Expensive sockets or adapters are not needed
Debugging and programming a production line board is possible.

An ICE uses custom hardware to emulate the target microcontroller. An ICD uses hardware on the target microcontroller to do some of the functions of an ICE. An ICD also employs software running on the target to do ICE-like functions and, as a result, relies upon the target microcontroller for some memory space, CPU control, stack storage and I/O pins for communication.

The MPLAB ICD 2 (In-Circuit Debugger 2) allows debugging and programming of PIC microcontrollers using the powerful graphical user interface of the MPLAB Integrated Development Environment (IDE). The MPLAB ICD 2 is connected to the design engineer’s PC using USB or RS-232 interface and can be connected to the target via an ICD connector.

MPLAB ICD 2 SYSTEM COMPONENTS:
In addition to the MPLAB ICD 2 module, the following components are required:

MPLAB IDE software (version 6.20 or later) – Installed on the PC to control MPLAB ICD 2.
RS-232 or USB cable – To connect the MPLAB ICD 2 module to a COM or USB port on the PC.
Modular interface cable – To connect the MPLAB ICD 2 module to a demo board or the user’s application.
Demo board or target application – To connect the PICmicro MCU with on- board debug capabilities to the modular interface (and the MPLAB ICD 2). Although the serial or USB communications from the MPLAB IDE to the
Power adapter(s) – To power MPLAB ICD 2 and the target application.

GPS – AN OVERVIEW:

The GPS (Global Positioning System) is a “constellation” of 24 well-spaced satellites that orbit the earth and make it possible for people with ground receivers to pinpoint their geographic location. The location accuracy is anywhere from 100 to 10 meters for most equipment. Accuracy can be pinpointed to within 1 meter with special military-approved equipment .GPS equipment is widely used in science and has now become sufficiently low-cost so that almost anyone can own a GPS receiver.

The GPS has three components namely:

The space segment: consisting of 24 satellites orbiting the earth at an altitude of 11000 nautical miles.
The user segment: consisting of a receiver, which is mounted on the unit whose location has to be determined.
The control segment: consists of various ground stations controlling the satellites.

GSM – AN OVERVIEW

GSM, Global System for Mobile communications, is today the most successful digital mobile telecommunication system. This second-generation (2G) system provides voice and limited data services and uses digital modulation with improved audio quality.

The different versions of GSM are:

GSM 900 band (850-915MHz up-link frequency and 935-960MHz downlink frequency)
GSM 1800 band or digital cellular system (DCS) 1800 band (1710-1785MHz up-link frequency and 1805-1880MHz downlink frequency)
Personal Communication service (PCS) 1900 band (1850-1910MHz up-link frequency and 1930-1990MHz downlink frequency)

SYSTEM DESCRIPTION

The entire Vehicle Monitoring and Security System is built around the PIC 18F8722 IC. It consists of 5 units comprising of

A Keyboard Unit
An LCD Unit
An RF Unit
A GPS Unit
A GSM Unit

Each unit in the Vehicle Monitoring and Security System undertakes a specific job and can be explained as follows:

The keyboard unit is used to type in the password and other information that needs to be keyed in.
The LCD unit is used to display the information that is keyed into the keyboard and for other menu applications.
The RF receiver unit is used to provide a unique code about each employee/passenger and for security applications.
The GPS module containing the GPS antenna receives the information from the GPS satellite in NMEA format.
The GSM module transfers the information got by the GPS receiver to the Base Station. The Base Station decodes the information to the required form.

THE KEYBOARD UNIT:

The keyboard is organized as a matrix of 4 rows and 3 columns. The columns are connected to an output port and the rows are connected to an input port. In this unit the keyboard is interfaced to the PIC18F722 IC with PORTB as the input port and PORTG as the output port. Pins RB2-RB5 of Port B and pins RG0-RG2 of Port G are connected to the keyboard.

If no key has been pressed, reading the input port will yield 0s for all rows since they are all connected to low (GND). It is the function of the PIC microcontroller to scan the keyboard continuously to detect and identify the key pressed. To identify a pressed key, the PIC microcontroller sends a 1 to each of the columns, starting with the first column; then it reads the rows. If the data read is all 0s, no key in that column is activated and the process is moved to the next column. A high is given to the next row, reads the columns, and checks for any 1’s. This process continues until the row is identified. After the identification of the row in which the key has been pressed, the next task is to find out which column the pressed key belongs to. This should be easy since the microcontroller knows at any time which row and column are being accessed.

THE LCD UNIT:

The LCD that is used in this project is LAMPEX 16101 LCD display, which is a one line 16-character display. The display contains two internal byte-wide registers, one for commands (RS=0) and the second for characters to be displayed. It also contains a user-programmed RAM area (the character RAM) that can be programmed to generate any desired character that can be formed using a dot matrix.

LCD PIN DESCRIPTIONS:
The LCD used for this project has 14 pins. The function of each pin is given in the table below:

LCD INITIALIZATION:

The module automatically performs initialization when powered on (using internal reset circuit).
The following instructions are executed during initialization:

CLEAR DISPLAY: The Busy flag is kept in the Busy state (BF=1).
Unit initialization ends. The time is 15ms.
FUNCTION SET: DL=1 ; 8-bits long interface data.
N=0 ; 1 line display.
DISPLAY ON/OFF CONTROL:
D=0 ; display off.
C=0 ; cursor off.
B=0 ; blink off.
ENTRY MODE SET:
I/D=1 ; increment (+1) .
S=0 ; No shift.
DDRAM: DDRAM is selected. Power on initialization depends on rise time of the supply when it is turned on.

When the above power supply condition is not satisfied, the internal reset circuitry doesn’t operate correctly. In this case, perform the needed initialization by sending function set instructions thrice from MPU after turning the power on.

For example, to designate an 8–bit data length, send the following instruction thrice:

When this ends, the module enters 8-bits data length mode without fail, then enters 4-bits data length instruction for 4-bits data length interface.

RF UNIT

The RF section consists of an RF transmitter and an RF receiver. The RF transmitter mainly consists of a remote key that contains a code hopping encoder, HCS301 along with 2 buttons and two LEDs. The RF receiver section consists of a Low Power ASK receiver IC. The key encoder will generate the company specific “Company ID”, which will be decoded by the low power ASK receiver IC. The LEDS are used to show the status of the remote key. The two buttons provided are used for ‘entry’ and ‘exit’. When both the buttons are pressed together, the system goes into a ‘panic’ state wherein the system will turn on the siren and immobilize the vehicle in emergency condition after a 10sec delay.

HARDWARE

POWER SUPPLY SECTION:

The power supply section consists of LM309, which is a 5V regulator fabricated on a single silicon chip. Current limiting is included to limit the peak output current to a safe value.

KEYBOARD SECTION:

Here we are making use of a 4X3 matrix keyboard. The columns are connected to an output port and the rows are connected to an input port. In this unit the keyboard is interfaced to the PIC18F722 IC with PORTB as the input port and PORTG as the output port. Pins RB2-RB5 of Port B and pins RG0-RG2 of Port G are connected to the keyboard. Pull-down resistors of 27k ohms are used.

LCD SECTION:

The LAMPEX 16101 LCD module is interfaced to the PIC18F8722 microcontroller. The data lines are connected to Port E and the control lines are connected to Port D of the PIC microcontroller. Only four of the eight data lines are used. The LCD is used in 4-bit mode with the hardware connected as follows:

PORTE bits 0-3 are connected to the LCD data bits 4-7 (high nibble)
PORTD bit 1 is connected to the LCD RS input (register select)
PORTD bit 2 is connected to the LCD R/W input (Read/Write)
PORTA bit 3 is connected to the LCD EN bit (enable)

RF SECTION:
RF TransmitterThe RF transmitter (2-button remote) mainly consists of a code hopping encoder, HCS301. S0 (pin1) and S1 (pin2) of HCS301 are connected to the two buttons, which are used as “Enter” and “Exit”. Pin 5(Vdd) is connected to +12V supply and pin8 is grounded. Pin 7 is the transmitter output. The LED is connected to pin 7.

PROJECT CODE:

its attached in this post.

CONCLUSION:

The outcomes of this project will be anticipated to show that it will alert unaware drivers from preventing a traffic accident, recognizing some unusual situations or gaining more response time whenever the EV (Emergency Vehicle) was approaching. Furthermore, its commercial achievements will especially be used in ITS (intelligent Transport System). It will pre-warn the involving drivers to avoid the emergencies and accidents as soon as he encounters an EV along the roadways.

BIBLIOGRAPHY:

BOOKS:

PIC18F8722 Microcontroller Data Sheet
Max 232 Data Sheet
LAMPEX 16101 LCD Data Sheet
Let Us C – Yashwant Kanetkar
Microcontroller Basics – Ayala
Electronic Communication- Wayne Tomasi

INTERNET:

www.google.com
www.microchip.com
www.epanorama.net
www.wirelessintegrated.com
www.wavecom.com
www.garmin.com
www.atmel.com
www.commlinx.com
www.alldatasheet.com

Attached Files:

vmss_code.zip (56 KB)

How-To: Build 10W Audio Amplifier

alman — Sat, 10 Oct 2009 19:08:51 +0000

Introduction: Amplifier device that accepts a varying input signal and produces an output signal that varies in the same way as the input but has larger amplitude. The input signal may be a current, a voltage, a mechanical motion, or any other signal; the output signal is usually of the same nature. The most common types of amplifiers are electronic and have transistors or electron tubes as their principal components. Electronic amplifiers are used in radio and television transmitters and receivers, audio and stereo systems, intercoms, and other consumer electronics devices. Amplifiers in their simplest form are built around a single transistor. In one type of single-transistor amplifier, known as a common-emitter circuit, a varying input voltage is fed to the base of the transistor, and the output appears at the transistor’s collector; the ratio of the output voltage to the input voltage is called the voltage gain. For many purposes a single transistor does not provide sufficient gain, or amplification.

In a cascade, or multistage, amplifier, the output of the first amplifying device (transistor) is fed as input to the second amplifying device, whose output is fed as input to the third, and so on until an adequate signal amplification has been achieved. In a device such as a radio receiver, several amplifiers boost a weak input signal until it is powerful enough to drive a speaker. Usually, multistage amplifiers are not made of discrete components, but are built as integrated circuits . Another less common group of electronic amplifiers use magnetic devices as their principal components. There are also many kinds of mechanical amplifiers, e.g., the power steering This audio amplifier project is a class AB audio power amplifier using a TDA2003 module power amplifier. It is easy to construct and has only a few external components. The module is designed with short circuit and thermal protection. It can drive loads as low as 1.6 ohm and is capable of delivering over 10 watts from a 16 V DC power supply.

The power supply required for is 8 – 18V DC at 1 Amp or more. Maximum output power will only be obtained with a power supply of greater than 1A at 16V DC, and using 2 ohm speakers (or 2 by 4 ohm speakers in parallel). However approximately 4W RMS can be obtained with a 12V DC, 1A supply into a 4 ohm load. The power supply should be well filtered to reduce mains hum, the on board capacitors alone are not adequate for this purpose but are necessary to ensure stability. Extra filtering is unnecessary if operating from a battery. If two boards are used for stereo, you will need to double the size of the power supply.

Circuit Diagram

10 W Audio Amplifiers Circuit diagram

Step Taken While Preparing Circuit:

The main purpose of printed circuit is in the routing of electric currents and signals through thin copper layer that is bounded firmly to and insulating base material some times called the substrata. This base is manufactured with an integral bounded layer of thin copper foil which has to be partly etched or other wise removed to arrive at a pre-designed pattern to suite the circuit connections.

From the constructors point of view the main attraction of using PCB is its role as the mechanical support for small components. There is less need for complicated and time consuming metal work or chassis construction except perhaps in providing the [mal enclosure. Most straight forward circuit designs can be easily converted into printed wiring layout the thorough required to carry out the conversion can often highlights any possible error that would otherwise be missed in convention point to point wiring. The finished project is usually neater and truly a work of art. Through proper design of PCB can get noise immunity. The fabrication process of the printed circuit board will determine to a large extent the price and reliability of the equipment. A common target aimed at is the fabrication of small series of highly reliable professional quality PCBs with low investment cost.

There are two types of PCB:-

Single sided board
Double sided board

Single sided board: The single sided PCBs are mostly used in endearment electronics where manufacturing costs have to be kept at a minimum however in industrial electronics. Also cast factors cannot be neglected and single sided boards should be used whenever a particular circuit can be accommodated on such boards.

Double sided boards: Double sided PCBs can be made with or without plated through holes. The production of boards with plated-through holes is fairly expensive. Therefore, plated through hole boards are only chosen where the circuit complexity and density dose not leave any other choice.

Layout Design:

The layout of a PCB has to incorporate all the information on the board before one can go on to the artwork preparation. This means that a concept, which clearly defines all the details of the circuit, is a prerequisite before the actual layout can start. The detailed circuit diagram is varying important for the layout designer but the must also be familiar with the design concept and with the philosophy behind the equipment. When designing the layout one should observe the minimum size (component body length and weight). Before starting to design the layout have all the required components to hand so that an accurate assessment of space can be made care must be taken so as to allow for adequate air flow after the components have been mounted. It might be necessary to turn some components round to a different angular position so that terminals are closer to the connections of other components. The scale can be checked by positioning the components on the squad paper. If any connection crosses, then one can reroute to avoid such condition. All common or earth lines should ideally be connected to a common line routed around the perimeter of the layout this will act as the ground plane. If possibly try to route the outer supply line ground plane. If possibly try to route the other supply lines around the apposite edge of the layout or through the center. The first step is to rearrange the circuit to eliminate the crossover without altering the circuit detail in any way.

Plan the layout as if looking at the top side of the board first this should be translated in reverse later for the etching pattern. Larger areas are recommended to maintain good copper adhesive. It is important to bear in mind always that copper track width must be at least to the recommended minimum dimensions and allowance must be made for increased width where termination holes are needed from this aspect it can become little tricky to negotiate the route for connections to small transistors. One can effect the copper interconnection pattern in the under side of the board in a way described below Make the interconnections pattern looking like conventional point to point writing by routing uniform width of copper from component to component.

Etching Process: Etching process requires the use of chemicals, acid resistant dishes and a running water supply. Ferric chloride is the maximum used solution, but other enchants such as ammonium sulfate can be used.

Nitric acid can also be used but in general it is not used due to the poisonous fumes. The pattern prepared is glued to the copper surface of the board using a latex type of adhesive that can be cubed after use. The pattern is laid firmly on the copper, use vary sharp knife to cut round the pattern carefully and remove the paper corresponding to the required copper pattern areas. Then apply the resist solution clean outlines as for as possible. While the board is drying to test all components. Before going to the next stage, check the whole pattern and cross check against the circuit diagram check for any foreign matter on the copper. The etching bath should be in a glass or enamel disk. If using crystal of ferric chloride these should be thoroughly dissolved in water to the proportion suggested. There should be 0.5 Lt. Of water for 125 gm of crystal. The board is then immersed in FeCl3 solution for 12 hours, in this process only the non hidden copper portion is etched out by the solution.

2FeCl3 + 2H2O + 3Cu 0 3CuCl2 + 2Fe (OH) 2

Waste liquid should be thoroughly diluted and buried in water land never pour down the drain. To prevent particles of copper hindering further etching, agitate the solutions carefully by gently twisting or rocking the tray. The board should not be left in the bath a moment longer than is needed to remove just the right amount of cooper. In spite of there being a resist coating, there is no protection against etching away through exposed copper edges; this leads to over etching. Have running water ready so that the etched board can be removed properly and rinsed; this will halt etching immediate.

Now the paint is washed out by the petrol. Now the copper layout on PCB is rubbed with a smooth sand paper slowly and lightly such that only the oxide layers over the Cu is removed. Now the holes are drilled at the respective places, according to component layout as shown in figure. Drilling is one of those operation that calls for great care, because most of the holes will be made and vary small drill. For most purpose a no. 60 drill all holes with this size first those that need to be larger can be easily drilled again with the appropriate large size.

Component Assembly: There should be no damage, such as hair line crack in the copper on PCB that could have a serious effect on the operational ability of the completed assembly holes.

Some photographs:

10W Audio Amplifiers front view

Power supply of 10W Audio Amplifiers

If there are, than they can and should be repaired first, by soldering a short link of bare copper wire over the affected part. The most popular method of holding all the items is to bend the wires further apart after they have been inserted in the appropriate holes. This will hold the component in position ready for soldering.

Some component will be considerably larger than others, occupying and possibly partly obscuring component. Because of this, it is best to start by mounting the smallest first and progressing through to the largest, before starting, makes certain that no further drilling is likely to be necessary, because access may be impossible later. When filling each group of components, mark off each one on the components list as it is fitted and, if we have to leave the job, we will know where to recommence.

Although transistors and integrated circuits are small items, there are good reasons for leaving the soldering of these until the last step. The main point is that these components are varying sensitive to heat and if subjected to prolonged application of the soldering iron, they could be internally damaged. All the components before mounting are rubbed with sand paper so that oxide layer is removed iron their tips. Now they are mounted according to the components layout.

Project by:Sanjay Yadav, All Saints’ College Of Technology, Bhopal.

50 FREE Amazing Blogger Themes

alman — Sat, 10 Oct 2009 12:31:37 +0000

Blogger may not be the first blogging platform you would choose, it does have a reputation of being lacklustre, featureless and the bog standard skins have the look of a site that was designed five years ago. The reputation is maybe a little bit exaggerated, but really, when was the last time you had a look at Blogger?
I have generally ignored Bloggers development over the last few years, and was pleasantly surprised at what I found when researching this post. Not only are there a healthy volume of widgets and addons, sprinkles of javascript and Ajax, there are also amazing themes that you would just not expect from Blogger. For me, the themes are certainly the greatest improvement, you may notice quite a lot of the themes below have been ported from Wordpress, which isn’t a bad thing. Long may it continue.

Better Comments Using One of 6 WordPress Plugins

alman — Sat, 10 Oct 2009 12:29:50 +0000

Bloggers love to have comments on their blogs. It builds social proof, enriches the content, fosters community and so on. Here are six plugins that you can use to boost the number of comments on your blog and make the commenting process more efficient.

1.Better Comments Manager

Replying to comments from your readers will make them come back in the future, because they will know that your care for them.

The “Better Comments Manager” plugin allows you to reply to the comments right from the Admin panel. In the absence of this plug-in, you have to visit the post individually and reply to the comment which is time consuming and tedious if you have tons of comments to reply.

2.Subscribe to Comments

By installing this plug-in in your WordPress blog your readers can get email notifications about the further comments on the post. When a reader comments in a post and checks the box to get E-mail notifications, it helps him to stay in touch with the comments and encourages him to come back to your blog and stay engaged in the discussion.

This helps to add more value to your post as more and more commenter’s exchange their ideas and views on the post.

3.WordPress Thread Comment

This plugin for WordPress allows the readers to reply to a specific comment, making it easier to follow the discussion. The plugin should also be compatible with most WordPress themes around, and installation is not that difficult.

4.IntenseDebate

This is one another cool WordPress plugin to consider if you are looking to get more comments and visits to your WordPress blog. This plug-in encourages your readers to actively participate in the discussion and it allows them to rate a comment posted with simple thumbs up or down buttons.

They can also leave active replies to the comments or start a new comment. Commenters can also subscribe to the replies and new comments such that they get email notification when a reply to their comment is received or any new comment is added to the post.

5.Absolute Comments

This plugin for WordPress also allows you to instantly reply to comments right from the admin panel.

The interesting feature of this plug-in is that it supports threaded comments, and if you have set to receive email notification, when a new comment is posted you can see a direct reply link to the comment in the email.

6.Contact Commenters

This is a great tool to interact with the commenters of your blog posts. By using this plugin you can send email to selected commenters, perhaps thanking their for their comments or asking their opinions on a related issue.

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