ETC system consists of an RFID
reader that continuously receiving RF signal and detecting the envelope of modulated signal. A Serial
RS-232 output which makes it easy to interface it to any microcontroller or
computer. The reader senses any RFID tag within a range of 50mm to 150mm and
outputs the tag data through both serial RS-232 connection and through TTL
pins. The demodulated serial data is compared to existing tag number and if
there any number matching with the received number then identifies presence of
that object/vehicle, and deducts the ticket amount from their account.
DESIGN
#include
<16F877A.h>
#device
adc=8
#FUSES
NOWDT //No Watch Dog
Timer
#FUSES
XT //Crystal osc
<= 4mhz
#FUSES
NOPUT //No Power Up
Timer
#FUSES
NOPROTECT //Code not
protected from reading
#FUSES
NODEBUG //No Debug mode
for ICD
#FUSES
NOBROWNOUT //No brownout
reset
#FUSES
NOLVP //No low voltage prgming, B3(PIC16)
or B5(PIC18) used for I/O
#FUSES
NOCPD //No EE
protection
#FUSES
WRT_50% //Lower half of
Program Memory is Write Protected
#use
delay(clock=4000000)
#use
rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#include
<string.h>
void
keyboard();
unsigned
char get_key();
unsigned
char colloc, rowloc, vehicle[3][3][10],a[], str1[12]="VEHICLE ID",
STR2[7]="TAG N0", STR3[7] = "AMOUNT", str_1[15] =
"ENTER DATA", data1[9] = "ENTER No",
str_2[5]="EXIT", veh1[] = "VEHICLE1",veh2[] =
"VEHICLE2",veh3[] = "VEHICLE3";
unsigned
int i,j,k;
unsigned
char keypad[4][4] = {'0','1','2','3',
'4','5','6','7',
'8','9','A','B',
'K','L','X','E'
};
//////////////////////////////time
out getc() ////////////////////////////////
char
timed_getc()
{
long timeout;
timeout=0;
while(!kbhit()&&(++timeout<10000))
delay_us(10);
if(kbhit())
return(getc());
else
return(0xff);
}
////////////////////////////////////////LCD //////////////////////////////////
void command()
{
output_low(pin_e0); //RS = 0
output_high(pin_e2);
delay_ms(3);
output_low(pin_e2);
//E = 0
}
void
data()
{
output_high(pin_e0); //RS = 1
output_high(pin_e2);
delay_ms(3);
output_low(pin_e2);
//E = 0
}
void
lcd_init()
{
output_d(0x38);
command();
output_d(0x0C);
command();
output_d(0x01);
command();
output_d(0x80);
command();
output_d(0x0E);
command();
}
///////////////////////////////GET
KEY ///////////////////////////////////
unsigned
char get_key()
{
unsigned
char x;
do
{
output_b(0xFF);
colloc = input_c();
colloc &= 0x0F;
}while(colloc!=0x00);
do
{
colloc = input_c();
colloc &= 0x0F;
}while(colloc==0x00);
while(1)
{
output_b(0x08);
colloc = input_c();
colloc &= 0x0F;
if(colloc != 0x00)
{
rowloc = 0;
break;
}
output_b(0x04);
colloc = input_c();
colloc &= 0x0F;
if(colloc != 0x00)
{
rowloc = 1;
break;
}
output_b(0x02);
colloc = input_c();
colloc &= 0x0F;
if(colloc != 0x00)
{
rowloc = 2;
break;
}
output_b(0x01);
colloc = input_c();
colloc &= 0x0F;
if(colloc != 0x00)
{
rowloc = 3;
break;
}
}
if(colloc == 0x01)
x = keypad[0][rowloc];
else if(colloc == 0x02)
x = keypad[1][rowloc];
else if(colloc == 0x04)
x = keypad[2][rowloc];
else
x = keypad[3][rowloc];
return(x);
}
/////////////////////////////// lcd
////////////////////////////////
void
string(char str[])
{
int
i=0;
lcd_init();
while(str[i]!='\0')
{
output_d(str[i]);
data();
delay_ms(3);
i++;
}
delay_ms(20);
output_d(0x01);
command(); }
/////////////////////////////////////////////////// READ
////////////////////////////////////////////////
void
read()
{
unsigned
char c;
for(i=0;i<3;i++)
{
i = 0;
for(j=0;j<3;j++)
{
for(k=0;k!='\0';k++)
{
c = vehicle[i][j][k];
c =
output_d(c);
data();
}
}
}
}
/////////////////////////// DEDUCT ////////////////////////////
int
deduct(char str[])
{
int x,a,b;
x = str[0]*100;
i++;
x = x + str[1]*10;
i++;
x = x + str[2]*1;
return(x);
x = x-10;
a = x/100;
str[0] = a;
a = x%100;
b = a/10;
str[1] = b;
b =
a%10;
str[2] = b;
}
///////////////////////// CHECK
//////////////////////////////////////
check(char
str[])
{
if(strcmp(str,vehicle[0][1])==0)
deduct(vehicle[0][2]);
else if(strcmp(str,vehicle[1][1])==0)
deduct(vehicle[1][2]);
else if(strcmp(str,vehicle[2][1])==0)
deduct(vehicle[2][2]);
}
//////////////////////////////////////////////////////////////////////////////
void
keyboard()
{
unsigned
char c;
int i,j,k;
string(str_1);
for(i=0;i<3;i++)
{
if(i==0)
string(veh1);
else if(i==1)
string(veh2);
else if(i==2)
string(veh3);
for(j=0;j<3;j++)
{
if(j==0)
string(str1);
else if(j==1)
string(str2);
else if(j==2)
string(str3);
for(k=0;k<10;k++)
{
c = get_key();
if((c=='E')||(c=='X'))
break;
vehicle[i][j][k]= c;
output_d(c);
data();
}
if(c=='X')
break;
}
if(c=='X')
{
string(str_2);
break;}
}
}
void
main()
{
int x;
lcd_init();
while(!input(PIN_A0));
keyboard();
while(1)
{
if(input(PIN_A1))
read();
for(i=0;i<10;i++)
{
a[i]=getc();
}
a[i]='\0';
x = check(a);
}
}
-----------------------------
