RFID Based Security System (AT89S52 + RFID)

please can u tell me about this circuit rfid based security system

Sir, what are the purpose of up and down keys in this project?

question

hi i am doing this home security project but it is my first so can u lead me ? i have some questions now. in the second picture there are a DEV2 chip and DEV3 coil, what are their type? so in the first picture we have a keyboard , for what do we need this ? and A connector exist on 2 side one is uln2830 and second is on AT89S52chip but others (B,C,D) connected only uln2830. do they connect to AT89S52 chip?

yes the ABCD is to be connected to the microcontroller.

i have some questions now. in the second picture there are a DEV2 chip and DEV3 coil, what are their type? so in the first picture we have a keyboard , for what do we need this ?

how and where should i connect my reader to the microcontroller in the ckt diagrm of rfid security system.........please tell me........thank u sir...........

hi frnds iam facing many prblms vth my ckt
RFID circuit vch published in EFY
i invested about 3k till now
please can u help me in interfacing of the at89s52 vth RFID module generally available in market

sir i have complted rfid based security system but i want to make it more secure and want to use keypad lock with it
i need theinformation regarding the interfacing of rfid and keypad lock

Hi

Can I know why you are using that external timer Circuit & can you say whether we can replace 89c51 in that circuit ?