Wednesday, 15 April 2015



While IoT projects were buzzing all around, I  decided  to make one and came up with Nucleus.It's a Smart lock based on Internet of things(IoT) built on Arduino uno and Ethernet shield.It can  be  accessed by a Key and internet through Software interface built in Java.There are many Electronic   locks available in Market ,but they are Expensive as  they  use  Fingerprints,   RFID card, Keypad (Password) as Key. I've used an I2C EEPROM as key which hardly costs 15 Cents resulting in an Inexpensive Key.Thus Nucleus can be Inexpensive as compared to other Electronics locks.As Nucleus is IoT lock,you can access it anywhere in the world if you are online.I will also develop Mobile apps to access the Nucleus though Mobile.Thanks to for providing free IoT services.Here's a snapshot of my project..

 Let's see what the project is made up of..


 Image source:

Arduino Uno is do-it-yourself kit with AVR Atmega328P Microcontroller which  can be programmed through IDE provided by Arduino and Codebender.  Its simple to use as there are many Libraries available online useful to interface different sensors and devices to Ardiono Uno.Learn more here.


Ethernet shield is built on Winzet W5100 which provides a network  (IP) stack capable of both TCP and UDP. It connects Arduino Uno to internet.I've used a MEGA Compatible Ethernet shield in Nucleus which is similar to Arduino's Ethernet Shield. In Nucleus,Arduino Uno interfaced with Ethernet shield acts    as Webclient.The Ethernet shield also has SD card slot to store and retrieve  data from Micro SD card. 


IC 24C32

I've used IC 24C32 as key.It   is  a  Serial  CMOS  EEPROM  that  uses  I2C Protocol to communicate with Micro-controller.It's a 8 Pin DIP IC. There  is a post in Arduino Play ground regarding interfacing 24C32 with Arduino Uno.


IC L293D

L293D is motor driver IC .I've used it to connect Motor to Arduino Uno.It's a 16-pin DIP IC.It has capability to control two Motors at time.   Engineer's    Garage has got nice post regarding L293D.It has internal   buffers    which     protect the circuit from back EMF of motor and avoid power loading.

Apart from the above parts, I've used a Geared Motor, Buttons, LED's ,  Connecting wires and Breadboard.


Key Features

  • Nucleus can be unlocked/locked by Multiple Authorized Keys and Software over Internet.

  •  Owner can Add or Remove Keys through Software.

  • The Software displays logs regarding the access of lock.

  • The Software show the status of Key add request. 

Circuit Diagram

Circuit Diagram
Circuit designed in fritzing

Actual Circuit: