Discussion in "Project Doubts" started by    onyot    Nov 23, 2010.
Tue Nov 23 2010, 06:56 AM
yes you can make it using ordinary push bottons......

see tutorial section of this site it also have a keypad circuit using simple switches and you can also google for it.....
Tue Nov 23 2010, 06:59 AM
yes. Thats the original concept of keypad. Did u see the code that i attached?

Ang also see this video im using ordinary tact switch here.

where do u having ur ojt onyot?
Tue Nov 23 2010, 07:04 AM
see this schematic this is simple 4*4 matrix keypad using simple switches...

Tue Nov 23 2010, 07:27 AM
what about 8 seven segment? do you have a link that I can use as a reference?
Tue Nov 23 2010, 09:05 AM
hi onyot.josephian
7-seg is an easy task not difficult
ru using 8 pieces of 7 segments
8051 has 4 ports and 1 segment piece need one port if we drive it by one port
it mean u only can attach a 4 segments to 8051 but not
there r multiplexing techniques that we can attach many 7- segments to only one port
Tue Nov 23 2010, 09:34 AM
hi onyot, there is also multiplexing technique in which u can save ports. There is a multiplexing tutorial here and u must read 8. I suggest u to start in one area like 4 example keypad interfacing an etc. Before u go to more complex things. Good luck to u yar!
Wed Nov 24 2010, 03:41 AM
Romel.. about that program you've given to me... what is the sample password? is it 12345?
Wed Nov 24 2010, 05:51 AM
hi onyot.josephian
i think code was 12345
romel can verify it
Wed Nov 24 2010, 05:56 AM
Majoka, in my project what is best to monitor, especially using a keypad? is it high or low? Is it okay to connect my keypad directly to the pins of 8051?

[ Edited Wed Nov 24 2010, 05:58 AM ]
Wed Nov 24 2010, 06:18 AM
#include <REG51.h>
#define display P3

sbit doorclose = P1^7;
sbit correct = P3^5;
sbit wrong= P3^4;
sbit key = P3^7;
void DelayMs(unsigned int);
void save (unsigned char);
void compare (void);

unsigned char keypad[4][3]= { '1', '2', '3',
'4', '5', '6',
'7', '8', '9',
'*', '0', '#'};

unsigned char displayb[4][3]= { 1 , 2 , 3 ,
4 , 5 , 6 ,
7 , 8 , 9 ,
0, 0 , 0};

unsigned char user[30]; //user is allowed to press 30 keys without entering
unsigned char q,a=0,z=0;
char t=1;
bit true;
char d;

void main(void)
{
unsigned char colloc,rowloc;

while(1)
{

do
{
}
while(colloc ==0xF0); // if any key pressed
DelayMs(1); // some delay
do
{
colloc &=0xF0;
}while(colloc==0xF0); // to verify is really key pressed

if(colloc !=0xF0)
{
rowloc=0;
goto next;
}

if(colloc !=0xF0)
{
rowloc=1;
goto next;
}
if(colloc !=0xF0)
{
rowloc=2;
goto next;
}

rowloc=3;
goto next;

next:
if (colloc==0xE0)
{
key=0; // verifying that key is pressed
DelayMs(145);
key=1;
display=((display & 0xf0) | (displayb[rowloc][0])); // display to 7 seg
}
else if(colloc==0xD0)
{
key=0; // verifying that key is pressed
DelayMs(145);
key=1;
display=((display & 0xf0) | (displayb[rowloc][1]));
}
else if(colloc==0xb0)
{
key=0; // verifying that key is pressed
DelayMs(145);
key=1;
display=((display & 0xf0) | (displayb[rowloc][2]));
}
DelayMs(100); // here this delay is important if this is less than 100ms then
// controller understand 1 key as press 2 or 3 times becoz that
//is fast as compaer o our pressing if u want to remove delay from here
// then increse the above 1ms to 100 ms
}
}

void save (unsigned char c)
{
if(c=='*')
{
if(a!=0)
a--;
return;
}

if(a==5 && c=='#')
{
a=0;
compare();

if(t==1)
{
if(true==1) // if match ok
{
DelayMs(800);
correct=0;
t=2;
for(d=0; d<7; d++) // on and after 10 sec off nw keypad can't get data
DelayMs(1000); // max delay u can get is DelayMs(65535) otherwise need looping for big delay
correct=1;
z=0;
a=0; // start agian from 0 location of array

}
else if(true==0)
goto error;

}
else if(t==2)
{
DelayMs(800);
doorclose=0;
t=1;
for(d=0; d<5; d++)
DelayMs(1000);
doorclose=1;
}
}

else if((a>5 && c=='#') || (a<5 && c=='#'))
{
error:
for(q=0; q<5; q++)
{
wrong=0;
DelayMs(420);
wrong=1;
DelayMs(420);
a=0;
}
z=z+1;

if(z==4)
{
for(q=0; q<10; q++)
{
wrong=0;
DelayMs(20000);
wrong=1;
z=0;
DelayMs(420);
}
}
a=0;
}
else
{
user[a]=c;
a++;

if(a==30) // if the user press 31 keys without entering it will automatically indicate an error
{
display=((display & 0xf0) | (displayb[3][1])); //brings a zero display on the seven segment
goto error; //redirect to error code
}
}

} //end of save

void compare (void)
{
unsigned char b;
for(b=0;b<5;b++)
{

true=1;
else
{
true=0;
break;
}
}
}

//---------------------------------------
// Delay mS function
//---------------------------------------
void DelayMs(unsigned int count)
{ // mSec Delay 11.0592 Mhz
unsigned int i;
while(count) {
i = 115;
while(i>0) i--;
count--;
}
}

What type of display is it? seven segment or lcd?

### Information

#### Conversation

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Tony Eldredge
Thu Jun 11 2020, 06:27 AM
anudee
sir could please send the code for I2C and wifi interfacing with 8051
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Does anyone have microcontroller programming software for STC15F104W (core 8051, 4 k, 128 byte, 6 I/O pin, UART ... DIL8), that works?
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Hi I am looking for a assembly language program for a digital decimal counter. Time counts max limit of 2 mins starting from 2.00 mins and ending at 0.00. time is to be displayed on 4 7-segment LED displays. Edsim51 simulator to be used. Thanks
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Sir kindly send the code file i2c for 8051
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ABEBE
how can get hadwere of this project
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Peter Parker
Is it possible to send multiple messages using only 1 GSM module?
Sat Feb 01 2020, 10:12 AM
Pearl Olin
Hello,

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