I made this project soon after completing my trainee period. This project was aimed at reducing human effort and allowing ease of access to differently-abled people. Home automation using bluetooth is really cheap to build and easy install in your home.
3. COMPANY PROFILE
• i3indya™ Technologies ( A unit of I THREE INFOTECH PVT
LTD ) with its foundation pillars as Innovation, Information and
Intelligence is exploring indefinitely as a Technology service
provider and as a Training Organization.
• i3indya™ was started by a group of entrepreneurs with a sole
mission of establishing a dedicated Research & Development
Cell and bringing the findings to the benefit of budding
Engineers. Little did they know that their efforts will bring an
enormous change in the world of technology & training. Today
in just four years of its existence, i3indya™ has a pan India
acclaim for its unmatched quality services.
5. WHAT IS HOME
AUTOMATION?
Home automation is the control of electrical/electronic
appliances reducing human effort. Home automation may
include centralized control of lighting, HVAC (heating, ventilation
and air conditioning), appliances, security locks of gates and
doors and other systems, to provide improved convenience,
comfort, energy efficiency and security. Home automation for
the elderly and disabled can provide increased quality of life for
persons who might otherwise require caregivers or institutional
care. The popularity of home automation has been increasing
greatly in recent years due to much higher affordability and
simplicity through smartphone and tablet connectivity.
7. COMPONENTS
• A microcontroller board(ATmega8)
• A 9v adaptor
• A no. of relays
• ULN2803 for driving relays
• A power supply circuit
• A cell-phone running Android OS
• And most importantly Bluetooth module
8. ATMEGA8L Features
• High Performance, Low-power AVR 8-bit Microcontroller.
• Advanced RISC Architecture
– 130 Powerful Instructions
– Most Single-clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16 MHz
• Nonvolatile Program and Data Memories
– 8K Bytes of In-System Self-Programmable Flash
– 512 Bytes EEPROM
– 1K Byte Internal SRAM
9. FEATURES
• I/O and Packages
– 23 Programmable I/O Lines
• Operating Voltages
– 4.5 - 5.5V
• Speed Grades
– 0 - 16 MHz
• Special Microcontroller Features
– Internal Calibrated RC Oscillator
– External and Internal Interrupt Sources
11. Pin Descriptions
• VCC : Digital supply voltage.
• GND : Ground.
• Port B (PB7..PB0) : Port B is an 8-bit bi-directional I/O port
with internal pull-up resistors (selected for each bit).
• Port C (PC5..PC0)/(ADC5..ADC0): Port C is an 7-bit bi-
directional I/O port with internal pull-up resistors (selected for
each bit).These pins also serve as analog inputs to the A/D
converter .
• PC6/RESET: If the RSTDISBL Fuse is programmed, PC6 is used
as an I/O pin. If the RSTDISBL Fuse is unprogrammed, PC6 is
used as a Reset input.
12. • Port D (PD7..PD0): Port D is an 8-bit bi-directional I/O port
with internal pull-up resistors (selected for each bit).
• AVCC : AVCC is the supply voltage pin for the A/D Converter. It
should be externally connected to VCC, even if the ADC is not
used.
• AREF: AREF is the analog reference pin for the A/D Converter.
AREF is used to set the TOP value for Analog to Digital
conversion.
13. WHAT’S A RELAY?
• A relay is an electrically operated switch. Relays are used
where it is necessary to control a circuit by a low-power signal
with complete electrical isolation between control and
controlled circuits, or where several circuits must be
controlled by one signal.
• In this figure, you can see that relay consist
of two separate and completely
independent Circuit (1-3 & 2-4). When the
electromagnet is ON, and it attracts the
armature. The armature is acting as a
switch in the second circuit.
• When the electromagnet is energized, the
armature completes the second circuit and
the light is ON and vice-versa.
14. TO DRIVE A RELAY…
• To drive a relay, we need the ULN2803A IC which is a high-voltage,
high-current Darlington transistor array. The device consists of eight
NPN-Darlington pairs that feature high-voltage outputs for
switching inductive loads. The collector-current rating of each
Darlington pair is 500 mA.
• Applications include relay drivers, lamp drivers, etc. The ULN2803A
has a 2.7-kΩ series base resistor for each Darlington pair for
operation directly with TTL or 5-V CMOS devices.
15. POWER SUPPLY
The above shown circuit is used to provide 5v regulated DC
power supply for our Home Automation circuit. This circuit uses
a 7805 5v regulator IC which is used to step down higher DC
voltages to +5v DC voltage. Two different capacitors are used in
this circuit to bypass any AC voltage component present.
16. ANDROID SMARTPHONE
• Any smartphone with any version of Android installed on it
will do the task.
• We are using an Android application named “Bluetooth
Terminal” which can be easily found on Google Play Store and
installed on the phone.
17. BLUETOOTH TERMINAL
• Bluetooth Terminal is an Android application that is a
VT-100 terminal emulator for communicating with
serial devices using a Bluetooth module.
• One can download this application from here
https://play.google.com/store/apps/details?id=es.py
masde.blueterm&hl=en
19. Description
• The Bluetooth module used in this project is HC-05 Linvor
Bluetooth module.
• It is an easy- to-use Bluetooth serial port protocol (SPP)
module, designed for a transparent wireless serial connection
set-up.
• The module has 34 PINS for configuration/interfacing of
Bluetooth module with microcontrollers.
• Bluetooth Serial module can communicate with the other
Bluetooth devices but requires at least two conditions:
(1) The communication must be between master and slave.
(2) The password must be correct.
20. Pins Description
• PIN1: UART_TXD, Bluetooth serial signal sending PIN, can
connect with MCU’s RXD PIN
• PIN2:UART_RXD, Bluetooth serial signal receiving PIN, can
connect with the MCU’s TXD PIN
• PIN11:RESET, the reset PIN of module
• PIN12:VCC, voltage supply for logic, the standard voltage is
3.3V
• PIN13:GND
• PIN 31:It is used to indicate module state.
• PIN32:Used to control LED indicating pairing. It will be steady
on when pairing is successful.
21. Hardware details
• Built-in CSR company Bluetooth chip BC417143.
• Bluetooth Technology v2.0+EDR.
• Coverage up to 30 ft/10 m.
• Built-in antenna.
• Power input: +3.3V DC.
• The maximum serial baud rate: 1382400 bps.
• Connection/non-connection status indicator.
• Frequency: 2.4GHz ISM band
• Modulation: FSK (Frequency Shift Keying)
• Emission power: ≤4dBm, Class 2
• Speed: Asynchronous: 2.1Mbps (max.)/160 kbps
• Dimensions: 26.9mm×13mm× 2.2mm
22. Communication between
Smartphone and MCU
• Start the Bluetooth manager(e.g. Bluetooth Terminal available
on Google play Store).
• Connect device(should find module).
• Pair.
• Send Commands from phone.
• See the magic being done.
24. USART/UART
UART stands for Universal Asynchronous
Receiver/Transmitter
UART helps to communicate with:-
• Another microcontroller
• Multiple microcontrollers
• Computer using a voltage level shifter or converter
• Other devices that are compatible with USART/UART
25. WHAT DOES UART DO?
UART can :-
• Transmit data using a buffer and a shift register
• Receive data using a shift register and buffer
• Create a frame of data that is recognised on both the
receiving end and the transmitting end.
All of this, works according to an agreed upon speed
from both sides, or with synchronous mode where
the clock line is directly connected.
26. Transmission/Reception in
UART
Data to be
transmitted
Data sent to
a buffer
Data is sent
to shift
register
Data moves
along
transmit wire
• This is how transmission is done.
• Receiving information is done in the reverse order
of transmission.
28. Baud Rate-the driving force
The baud is the clock that pushes the data
along the line.
In USART, a clock wire must be connected between
each microcontroller. This wire will pulse like a
heartbeat. In the case of asynchronous(UART), each
microcontroller has its own clock, the clock(baud
rate) at transmitter and receiver end must be same
i.e. the receiving microcontroller must be receiving
data at the same pace at which it is transmitted.
29. Initializing the UART
Function to initialize the UART :-
void UART_INIT(unsigned int baud)
{
UBBRH=(unsigned char)(baud>>8);
UBBRL=(unsigned char)baud;
//Enable the receiver and transmitter
USCRB=(1<<RXEN)|(1<<TXEN);
UCSRC=(1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
}
• When TXEN is set(Transmitter enabled), the general
purpose function of that pin is not available until TXEN is
disabled. Same idea goes for RXEN pin.
31. RECEPTION
Function for receiving :-
unsigned char UART_Receive(void)
{
while(!(UCSRA&(1<<RXC));
//wait for RXC to not have 0
return UDR; //get that data out of there and back to
the main program
}
32. UART I/O Data Register-UDR
UART Control and Status Register A-UCSRA
REGISTERS
33. UART Control and Status Register B –
UCSRB
UART Control and Status Register C – UCSRC
36. PCB LAYOUT
• To the left is the actual PCB
layout of the product.
• This shows both the
bottom and top copper
layers.
• This image also shows the
silkscreen for placing the
components on the PCB.
37. • The actual product contains all of the above
mentioned/explained components.
• These components are soldered on a home
made PCB(printed circuit board).
• The product needs some improvisation will be
ready to install at home/office.
• The home automation board has small
dimensions and can be easily installed by any
electrician.
