Electronic Combination Lock using IC LS 7220
Electronic Combination Lock Circuit
Description
This is the circuit diagram of a simple electronic combination lock using IC LS 7220.This circuit can be used to activate a relay for controlling (on & off) any device when a preset combination of 4 digits are pressed.The circuit can be operated from 5V to 12V.
To set the combination connect the appropriate switches to pin 3,4,5 and 6 of the IC through the header.As an example if S1 is connected to pin 3, S2 to pin 4 , S3 to pin 5, S4 to pin 6 of the IC ,the combination will be 1234.This way we can create any 4 digit combinations.Then connect the rest of the switches to pin 2 of IC.This will cause the IC to reset if any invalid key is pressed , and entire key code has to be re entered.
When the correct key combination is pressed the out put ( relay) will be activated for a preset time determined by the capacitor C1.Here it is set to be 6S.Increase C1 to increase on time.
For the key pad, arrange switches in a 3X4 matrix on a PCB.Write the digits on the keys using a marker.Instead of using numbers I wrote some symbols!.The bad guys will be more confused by this.
Electronic Lock Circuit Diagram .
Pin Assignment of LS7220.
Parts List
C1 1 1uF 25V Electrolytic Capacitor
C2 1 220uF 25V Electrolytic Capacitor
R1 1 2.2K 1/4W Resistor
Q1 1 2N3904 NPN Transistor 2N2222
D1 1 1N4148 Rectifier Diode 1N4001-1N4007
K1 1 12V SPDT Relay Any appropriate relay with 12V coil
U1 1 LS7220 Digital Lock IC
S1-S12 12 SPST Momentary Pushbutton Keypad (see notes)
HD1 1 12 Position Header
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Hello, please I want toSimple electronic combination lock circuit
and circuit pcb
And please send
hi can u tell me the alternate of ls 7220 or can u tell me the place where i can buy it in karachi pakistan.
I want to make the simple project for digital lock. I am in 3rd semester, webmaster, would you help. I need the help of people
kindly send me the pcb layout for digital lock code using IC LS7220.thank you
what is the price of LS 7220…????
what is HD1..?
is the IC need to programed at fisrt, for entering the right code? and, how to make the analog lock, which it turned by relay? thanks
I too would like a PCB Layout of this project. I have been trying to make one myself but with very little success. Please help.
I WANT ASSEMBLE THE 6 CHANNEL OUTPUT HOMETHEATRE AMPLIFIER USING 4x35WATTS TDA7383 QUAD IC. KINDLY GIVE THE DETAILS. THANKING YOU.
Hi Sundeep as per proelectron standards first digit stands for material. B stands for silicon and if it is A it is germanium. The second digit indicates the application C stands low power small signal low frequency transistor. 107 stands for the type number (may be voltage current etc)for details refer manufacturers catalog. the suffic A, B, C stands for small signal current gain of the transistor. A 100 t0 250, B 200 to 450, C 400 to 900.
The following do not fall on any standards.
SL 100 & CL100 S stands for the manufacturer Semiconductor India Ltd., C stands for Continental devices India Ltd. L100 stand for medium power NPN transistor. if it is K100 stands for medium power PNP transistor. BEL100N and BEL100P are also similar trasistors.
what does BC stand for in BC107 SL stands for in SL 100 CL stands for in CL 100
Ilove the circuit. What I need to know is the Header (HD1). What is it? Is it part of the keypad or do I need to buy it?
Hi there,
Could you please explain what is header (HD1)?
Thanks in advance.
please! i have project based on sequence timers.
could u display a circuit about sequence timers using 555 0r 8051 micro controllers?
Hello admin your site is really interesting and helpful I’m impressed.. : )
please! please! please!
i have project based on solenoid.
could u display a circuit about solenoid??
please again!!
i still have problem with this will you please make it more simpler that would be very much kind of you
Hello, please I want to know how smart card digital lock system can be realized with possible circuit diagram.
really a valuable circuit, but what is a 12 position header. sorry to ask i am new to electronics.
I would like to have a PCB layout for the digital lock
Currently I dont have a PCB lay out of this circuit.I tested this circuit on the bread board only.
You can easily make the PCB by yourself using software like PCB123.Just have a try.
If you cant make one properly, mail me. I will make one for you.
regards CT
I am student of 4th year.let me know that i should make project on digital lock code or not???kindly send me the pcb layout for digital lock code.
thank you
i will add one soon
good website…….please send me the circuit of instrumentation amplifier………
please send price of IC LS7220 thanks
Самый интересный web сайт о новинках гаджетах, а также тесты мобильных устройств
Thanks
Hi there.
Just wanted to let everyone know that LS7220 ICs can be purchased over ebay.
i will add them soon
Hi hello
could you please post the circuite diagram of timer with 555(for power equipment)
and second
would you please post the circuite (and information ) about motor control( with pc)?
thanks
The ckt. used for making an electronic combinational lock is very easy to understand.
I must congratulate the concerned people for making site user friendly..
Hi Hello webmaster ! thanks i had been looking for this for a long time.nice work.would you please post the circuit diagram of a fridge door alarm.thanks in advance.