Introduction: Programmable Security Lock Using Arduino

Picture of Programmable Security Lock Using Arduino

Arduino based programmable security lock for locking electronic appliances. The appliance can be unlocked only if the correct password is fed.

- The numeric password can be of any length of our choice ( max.length 15).

- Password programmable by SMS from a unique authorised number.

- SMS Commands, Alerts , Maximum 3 wrong attempts , Emergency freeze mode for increased security.

- Developer : Mitu Raj

Step 1: Components Required

1) Arduino UNO

2) SIM 900A GSM module

3) 4x4 matrix keypad

4) 5V Relay Module

5) 16x2 LCD display

Step 2: Circuit Connection

Picture of Circuit Connection

1) 4x4 Keypad pins 1-8 are connected to D2-D9 pins of Arduino. If you get incorrect response from the keypad , it maybe because you connected it in the reverse order. Take a note of this.

2) SIM 900A GSM module's RX and TX are connected to D11, D10 respectively. We use these pins as software serial . GND of GSM is connected to Arduino GND .

3) Use 9V 2A adapter as power supply to GSM module. 2A is preferred over 1A rated adapter. The same may be used to power the Arduino too. Your wish.

4) The 5V relay module is connected to D12 pin. and "Busy" status LED . Choose the relay wisely ( generally capable to switch 24V DC/ 240V AC 5A rating).

5) Interface the LCD display as in the circuit diagram shown.

You are ready to GO !!!

Note : The Led in 13th pin is connected in reverse manner in the circuit diagram . please connect the positive of the Led to the Vcc of the arduino , and the negative to D13 via the resistor . Also connect the analog pins to LCD in the reverse order to that in the circuit diagram .

Step 3: Notes

Picture of Notes

Implement individual Keypad test , GSM test and testbench in Arduino before you proceed to the complete circuit implementation ( go through guidelines too in main code folder ). The necessary files and instructions have been attached with this. Also make sure that your Arduino IDE contains keypad.h , softwareserial.h libraries.

link to my paper :
For any queries please contact me

Thank You !

Mitu Raj


mail :

Step 4:


wan.norzahidah1997 (author)2017-07-19

Can i have the code?

please contact in mail

ShafiqR8 (author)2016-12-05


AmCoder (author)ShafiqR82016-12-06

please find it in the Attached RAR file

koruptx2 (author)2016-08-10

Sim 800 L GSM Module will do it ?

AmCoder (author)koruptx22016-08-10

yea it gotta work ! :)

ryasey made it! (author)2016-07-12

I made it. Quite interesting. Thank you for the project. I am actually presenting this for my final year project. technical and applied physics

AmCoder (author)ryasey2016-07-15

good luck man ;)

AmCoder (author)2016-04-23

u are welCome :)

About This Instructable




More by AmCoder:Distant Weather Monitoring Using Arduino and ESP8266Design of UART in VHDLSetting up Raspberry Pi 3
Add instructable to: