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I had built and worked similar project using ATMEL 89C52 and RFID bought from united77.com. The relay on board can be connected to any electromagnet to lock the door. they provide all details including schematics, PCB's and components with project description. Hope this will help you. The said kit is also available without RFID option. Chekout their website.
thanks for reply.can i use 2N4307?Because my school dont provide 2n2222 , but there is 2n4307.
Added after 2 hours 5 minutes:
erm mine teacher ask me test with relay RY5WFZ-K , instead of the magnetic lock.how do i connect the relay?pin 1 and 16?and from the power supply, there is 4 wire , 1 for 5 v , 1 for 12v.the two gnd wire should be connected together?
check page 7 of the data sheet frm which you will know the pin config (schematic)
Its a DPDT relay (Double Pole Double Throw)
Pin 1 and 16 is the relay coil,
pin no 8 is Common and 4 & 6 is its NC and NO respectively
and pin no 9 is Common and 13 & 11 is its NC and NO respectively
hey.. 8051 give a 3.3 volt.if i use direct power of 3.3 volt from the power supply , it can work.but when i use 8051 to give a high, it doesnt work.the circuit is working properly, i think the main part is on the 8051 part.
which port pin are you using? whats the value of the external pull up resistor
P0 does not have internal Pull up resistor so when you make any pin of P0 high it will be floating, so you will require external pull up resistor
P1, P2, P3 has internal 10k pull up so when you make any pin high the current will flow through the 10K resistor so if you require high current you will require external pull up resistor
how did u solve it? what changes did u make?
u require 12v for the relay so no need to change the transistor u can use BC 547 u may have to change the value of the resistor since you are using 3.3v as Vcc