Home Automation and Security System using Microcontroller ATMEGA8 with Arduino Programming

Home automation and security systems have become very popular these days, today industrial automation techniques are widely adopted by luxurious homes and apartments. Here I’m going to give a worthy home automation security and monitoring project for engineering students. On the whole this microcontroller based home automation system with security performs the following series of processes, making it the best home automation system.

  • Sense the temperature level of the room and monitor it using LEDs.
  • Controls the temperature using exhaust fan.
  • Automatically open and close the door to make fast temperature control.
  • Pump water if necessary, in case fire is detected.

I happened to develop this for a science fare exhibition in one of the schools. You can also make use of this kitchen automation as major project for engineering or diploma final year.

School projects:

Components required

  1. Arduino UNO
  2. IC 74138
  3. L293D
  4. Exhaust fan (12V)
  5. Vehicle glass washer pump motor (12V)
  6. MQ6 GAS sensor
  7. Thermistor (High resistance type)
  8. Transistor (BC548x3)
  9. Buzzer 5V
  10. LEDs (Greenx3, Yellowx3, Redx2)
  11. POT (10Kx2)
  12. Resistor (1Kx3, 10k)
  13. Relay 12V
  14. DVD loader tray
  15. 12v Power supply
  16. USB cable

Setting up the project

Built around ATMEGA8 microcontroller, the main advantage of this system is that it uses Arduino programming which makes easy embedding of program and at the end of the day it leads to a drastic reduction of cost from about Rs.1500 to around Rs.80.

For demonstration purpose I have used a DVD loader assembly to open and close the door, it has an inbuilt open close sensor which I have used here. Moreover the MQ6 GAS sensor for detecting the leakage of LPG is an added advantage of this project. When leakage is detected it should run an alarm and switch on exhaust fan to reduce the density of GAS.

Circuit Diagram

microcontroller based home automation system with security

Working of home automation and security system

Now let me get in to the working of our home automation and security system section by section. The main sensors that I have used here is a thermistor to detect the temperature level and a MQ6 GAS sensor to detect the presence of LPG.

Thermistor Section

  • Firstly read the temperature value from thermistor and monitor on LED with the help of 74328 IC which is a 3 to 8 decoder.
  • Two threshold values are used, first one to enable open/close of the door and the other one for fire alarm.
  • The temperature level from thermistor is checked. If the level is less than first threshold then it does nothing. Else if it’s greater than the first threshold it opens the door with the help of ‘ON OFF touch switch’ (Eject button) in DVD loader assembly, thereby switching on exhaust fan.
  • If the temperature level is greater than second threshold level (it means there will be a presence of fire) then the controller will switch on water pump motor to extinguish the fire.

MQ6 GAS Sensor Section

  • Then the controller listens to the gas sensor output and compares it with a threshold value, when it’s greater than threshold, controller will switch ON exhaust fan and make buzzer ON and OFF to make “beep” sound.
  • If the level comes down it switches off the fan and closes the door.

MQ6 -1

MQ6-2

Programming Explanation

  1. Programming Steps
  2. Variable declaration
  3. Pin initialization
  4. User defined sub functions
  5. Infinite Loop

Variable Declaration

  • Declare four variables A,B,C,D.
  • A →Stores the value read from thermistor via analog pin ADC0.
  • B→Stores the mapped values of ‘A’.
  • As the arduino has a 10bit ADC the value can vary from 0 to 1023. To monitor these analog temperature values using 8 LEDs we have to map 0→1023 to 0→8. These mapped values are stored on an integer variable ‘B’.
  • C →Store the analog value read from MQ6GAS sensor through analog pin ADC1.
  • D →Stores mapped values of ‘C’.
  • Here mapping to 0-100 (Just to get a threshold for the program).

Pin Initialization

Next initialize the input and output pins which include analog and digital pins. Here we are specifying whether the pin is input or output, pin Mode command is used for it.

User Defined Sub Functions

Then create separate sub functions for open door, close door, buzzer, water pumping, fan ON and fan OFF.

Infinite Loop

  • In loop function analog values are read from both thermistor and GAS sensor and then mapped to corresponding variables.
  • Then it checks the temperature value and then sets the corresponding pins as binary value (pin 0, 1, 2 in Arduino), which is decoded by a 3 to 8 decoder IC 74138. It then drives corresponding LEDs.
  • It then checks the GAS sensor mapped value, if it’s greater than 50 (threshold) then turns ON the fan and makes buzzer ON for some time and then fan is switched OFF.
  • Checks the temperature level and if the value is in between 3 (first threshold) and 6 (second threshold), then opens the door and turns ON the fan.
  • If the value becomes less than 3 it switches OFF the fan and closes the door.
  • If the door is either fully opened or fully closed then the controller stops the current supply to the door motor, thereby saving current and ensuring long life of door motor. It is achieved via special arrangements in the DVD loader.

DVD Drive

  • When the door fully opens, the middle pin of DVD loader gets connected to +5V. Similarly when it’s fully closed it gets connected to ground supply, the middle pin is connected to the controller and it disconnects the motor supply according to the values of this input.
  • In case temperature level exceeds the value 6 (indicates the presence of fire) then it switches ON the water pump and makes buzzer ON sometime.
  • When temperature level decreases, turn OFF the water pump.

Automation and Security System Embedded Program Code

You can request the Microcontroller program codes for Automation and Security System project.
Request the program codes from the following link
CircuitsGallery Embedded programs

Hope this was helpful, stay tuned as we’ll be coming up with more arduino home automation DIY projects ideas.

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