RFID Based Attendance System (AT89S52 + RFID)

Can anybody tell how it is work .

cn any1 giv m a pcb layout for rfid based attendance system project using AT89S52?

this might help the ones requiring a vai27 diagram

vai27 diagrams

sir i have run program in keil soft then it shows me 2 errors after solving error it shows warnings as below


Build target 'Target 1'
assembling 2047.asm...
linking...
*** WARNING L4: DATA SPACE MEMORY OVERLAP
FROM: 0000H
TO: 005BH
Program Size: data=100.0 xdata=0 code=7944
creating hex file from "2047"...
"2047" - 0 Error(s), 1 Warning(s).



sir how can i solve this problem????
because of this i can not burn hex file to controller ic
sir plz help me out.....

Sir,
1)Master Card is same as user card(looks and function)?
2)Master card has to be purchased separately than user cards?
3) Or it has to be programmed?????
4)If not connected to PC,then why MAX232 & RS232 is used in the ckt.??
5)10 k Variable resistor is connected to which three connnections....?
6) Is it compusary to use keyboard????If not used than what changes occur.....?
7) To add master card program has to be changed????

Plsssssss......Sir ..Reply SOON......Its very urgent......Pls.....

hi,
I am hemant. I was decide to do this project in my final yrs be, but it is getting me diffult to prepare a pcb..........will you plz make me available the pcb print.
thnx

Sir, I have implemented the same project using EM18 RFID module. I have checked the module on DSO for its working. It is working properly. But the LCD interfaced with the 8051 uC is not showing any results. It is only showing boxes. Please help Sir, I need to submit this project next week. I have used USB for 5V power supply.

which microcontroller are you using?

AT89S51 MIcrocontroller.

Also please tell which burning program to use.

I have tried using PROG51 IDE AND SPI PGM but showing some memory problem perhaps like'out of memory, should be in the range 0-4095'.

What do you suggest ?

Kindly tell.
thnks !