#Pin keypad layout how to#
#Pin keypad layout password#

The above mentioned process continues till output Q4 – pin #10 turns high.As soon as you press the button at pin #2, high signal reaches the clock pin, which makes output Q1 – pin #2 low and Q2 – pin #4 high.Once the high signal reaches pin #14, the output Q0 – pin #3 turns low and output Q1 – pin #2 turns high, now we need to press the 2 nd digit of the password, which is the button connected to pin #2.When we press the button connected at pin #3 which is the first digit of the password, sends a high signal to clock pin #14. When the circuit is turned ON, the output pin #3 (Q0) will be high initially.

#Pin keypad layout password#

The output from Q0 to Q9 is in the sequence (pin number): 3, 2, 4, 7, 10, 1, 5, 6, 9 and 11 respectively.īy now you should have some understanding how IC 4017 functions, now let’s see how the sequential output can be developed into an electronic password lock circuit.This is true for outputs from Q0 to Q9 and repeats. When you apply another clock pulse Q2 turns high and Q1 turns low.

When no clock pulse is applied initially, output Q0 will stay high, when you apply one clock pulse, output Q1 turns high and output Q0 turns low. Pins 1 to 7 and 9 to 11 are outputs: There are 10 output pins which turn high one by one sequentially (reset of the output stays low).Pin 12: Carry out – This pin is used for cascading two or more IC 4017, this pin turns high if the count of the IC exceeds 9.When pin #13 is connected to high, the clock pulse applied on pin #14 gets ignored by the IC. Pin 13: Clock enable – when this pin is connected to ground, the clock pin #14 accepts clock signal.Pin 14: Clock input – we need to apply a clock pulse to this pin to make the IC count from 0 to 9.Pin 15: Reset pin, during normal operation the pin must be grounded, when this pin connected to high the count of the IC will get reset.To understand how the circuit functions, we need to know the pin configuration of IC 4017 and how the IC functions: The relay we are going to use in the circuit comes in a breakout board and the input of the relay is active low, meaning if we apply GND signal to the input terminal the relay gets activated. The proposed electronic lock circuit consists of just few components an IC 4017 which is the heart of the circuit, 11 push buttons for entering the pin number, 5 diodes to prevent short-circuit between output pins, couple of LEDs for indicating the status whether the circuit is locked or unlocked, couple of pull-down resistors, couple of current limiting resistors and a low power NPN transistor for triggering the 5V relay.

#Pin keypad layout how to#

How to set a new password / change password:.