control ur appliances by using bluetooth

1. Bluetooth based home
appliances control

2. Introduction
This project is designed to operate electrical loads using any
Bluetooth enabled device. The system operates electrical loads
depending on the data transmitted from the Android application
device. Operating conventional wall switches is difficult for elderly or
physically handicapped people. This proposed system solves the
problem by integrating house hold appliances to a control unit that
can be operated by a smart-phone/Tablet etc.

3. Bluetooth communication
Bluetooth is a wireless technology standard for exchanging data over
short distances (using short-wavelength UHF radio waves in the ISM
band from 2.4 to 2.485 GHz) from fixed and mobile devices, and
building personal area networks (PANs). Invented by telecom
vendor Ericsson in 1994, it was originally conceived as a wireless
alternative to RS-232 data cables. It can connect several devices,
overcoming problems of synchronization. Bluetooth is managed by
the Bluetooth Special Interest Group (SIG), which has more than
25,000 member companies in the areas of telecommunication,
computing, networking, and consumer electronics.

4. Design principle and operation
In this project Bluetooth module is interfaced to 8051 microcontroller through a
DTMF decoder. This Bluetooth receives the DTMF commands from the mobile
phone using Bluetooth communication device using wireless communication. The
program which is written to the 8051 microcontroller communicates with
Bluetooth module to receive the commands through a decoder after a successful
pairing. The Bluetooth based Wireless Appliance control system accepts input
from a mobile console. The mobile sets must have a key pad, few keys from that
keypad designated for control of the Appliances connected at the user end. In this
project ‘1’,’2’, ‘3’,’4’,’5’ & ’6’ of the keyboard is activated, each key is assigned with
one of the appliance through an non potential contact relay. On pressing a Key
automatically one DTMF code is generated and transmitted. Microcontroller
switches the electrical loads automatically based on the commands received from
the Bluetooth. All the loads are connected through a solid state relay and motor
driver.

5. Block diagram

6. Sections description
Power supply
In this we are using Transformer (0-12) v, 1Amp, IC 7805 &
7812, diodes IN 4007, LED & resistors. Here 230V, 50 Hz ac
signal is given as input to the primary of the transformer and
the secondary of the transformer is given to the bridge
rectification diode. The o/p of the diode is given as i/p to the
IC regulator (7805 &7812) through capacitor (1000mf/35v).
The o/p of the IC regulator is given to the LED through
resistors.

7. Circuit diagram
LED
LED
1k
- +
IN4007 * 4
GND
9-0-9Vac/1Amp
1000uF/35V
7812
POWER SUPPLY
+5V
+12V230VAC
50Hz 2.2k
7805

8. DTMF decoder
Introduction to DTMF
DTMF means: Dual Tone Multi-
Frequency, There is no base band
multiplexing done on DTMF signals.
The signal generated by a DTMF
encoder is a direct algebraic
summation, in real time, of the
amplitudes of two sine (cosine)
waves of different frequencies. i.e.
pressing '1' will send a tone made by
adding 1209 Hz and 697 Hz to the
other end of the line.

9. DTMF decoder
There are many ways to detect and decode these DTMF tones. One idea could be
an eight sharp-tuned filter combination with detection circuits. Needless to say,
this is very impractical, considering the various ICs (Integrated Circuits or 'chips')
made by different manufacturers all over the world. Most of these ICs do not
require more than one (inexpensive) 3.58 MHz x-tal or resonator and the power
circuitry. Usually the output is 4-bit binary + 1 strobe.
Decoder IC Operation.
The Bluetooth receiver receives the frequency modulated DTMF signals and the
output (DTMF tones) are fed to the dedicated IC KT3170 which is a DTMF-to-
BCD converter. This IC when fed with the DTMF tones gives corresponding BCD
output; for example, when digit 1 is pressed, the output is 0001 and when digit 4
is pressed the output is 0100. This IC also requires a 3.58MHz crystal for its
operation.

10. Circuit diagram
1m
15
DTMF DECODER
LED
1
14
0.1uf
0.1uf
18
95
2
17
11
CM 8870
4
12
330e
8
signal i/p
6
7
16
3
CRYSTAL
VCC
101m
13
330k

11. Mother board
The motherboard of this project is designed with a MSC –51 core compatible
micro controller. The motherboard is designed on a printed circuit board,
compatible for the micro controller. This board is consisting of a socket for micro
controller, input /output pull-up registers; oscillator section and auto reset
circuit.
Micro controller core processor:
Introduction
Despite it’s relatively old age, the 89C51 is one of the most popular Micro
controller in use today. Many derivatives Micro controllers have since been
developed that are based on--and compatible with--the 8051. Thus, the ability to
program an 89C51 is an important skill for anyone who plans to develop
products that will take advantage of Micro controller.

12. Mother board
The memory types are illustrated in the following graphic.
They are: On-Chip Memory, External Code Memory, and
External RAM. On-Chip Memory refers to any memory
(Code, RAM, or other) that physically exists on the
Microcontroller itself. On-chip memory can be of several
types, but we'll get into that shortly.
External Code Memory is code (or program) memory
that resides off-chip. This is often in the form of an external
EPROM.
External RAM is RAM memory that resides off-chip. This
is often in the form of standard static RAM or flash RAM.
Code Memory
Code memory is the memory that holds the actual 8051 program that is to be
run. This memory is limited to 64K and comes in many shapes and sizes: Code
memory may be found on-chip, either burned into the Microcontroller as ROM
or EPROM. Code may also be stored completely off-chip in an external ROM or,
more commonly, an external EPROM.

13. Mother board
Auto reset circuit
The auto reset circuit is a RC network as shown in the mother board circuit
diagram. A capacitor of 1-10mfd is connected in series with a 8k2 resister the R-C
junction is connected to the micro controller pin –9 which is reset pin. The reset
pin is one when ever kept high( logic 1) the program counter (PC) content resets
to 0000h so the processor starts executing the program. from that location.
When ever the system is switched ON the mother board gets power and the
capacitor acts as short circuit and the entire voltage appears across the resistor,
so the reset pin get a logic 1 and the system get reset, whenever it is being
switched ON.

14. Circuit diagram
RST
10uF
22pF
22pF
8.2k
4 - 12Mhz
VCC=+5vdc
AT89C51
9
18
19
29
30
31
1
2
3
4
5
6
7
8
21
22
23
24
25
26
27
28
10
11
12
13
14
15
16
17
39
38
37
36
35
34
33
32
RST
XTAL2
XTAL1
PSEN
ALE/PROG
EA/VPP
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
P2.7/A15
P3.0/RXD
P3.1/TXD
P3.2/IN T0
P3.3/IN T1
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
P0.0/AD0
P0.1/AD1
P0.2/AD2
P0.3/AD3
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
MICROCONTROLLER

15. Mother board
Crystal Oscillator
The 8051 family
microcontroller contains an
inbuilt crystal oscillator, but
the crystal has to be connected
externally.
This family of microcontroller can support 0 to 24MHz crystal and two numbers
of decoupling capacitors are connected as shown in the figure. follows, . These
capacitors are decouples the charges developed on the crystal surface due to
piezoelectric effect. These decoupling capacitors are normally between 20pf to
30pf. The clock generator section is designed as

16. Motor driver
The D.C. Motor used in this project operates at
12 volt and carries approximately 400mA of
current. The motor driver is designed to inter
face the motor with micro controller. The micro
controller out put is +5volt and can maximum
give a current of 5mA. The driver stage changes
the current and voltage level suitably to drive
the motor. The driver stage not only drives the
motor but also helps to control the direction of
rotation. As the output current (Ic) is large the
driver section requires a Darlington pair to
switch the load. The Darlington pair I.C. TIP 122
is used here for designing.

17. Solid state relay
Here in this section, to activate/deactivate the load a solid state device is
used to drive the load but the load is an AC load for that we have to isolate
that for that we have used an opto-isolator (MOC3201) as a driver. It is an
electronics device which isolates between input to output, that device is
consisting of a LED and a DIAC which is fabricated on a single chip.
Whenever a high voltage is given as input to the LED the LED gets forward
biased which in turn ON the LED, the light falls on the DIAC which in turn
the DIAC thus gets a sufficient current to drive the gate of the TRIAC to
make turn ON the LOAD.

18. Circuit diagram

19. Buzzer driver
This section interfaces one audible piezo electric buzzer with the controller. The
controller activates the buzzer whenever there is any valid data receives.
PIEZO ELECRTIC BUZZER:
It is a device that converts electrical signal to an audible signal (sound
signal).The Microcontroller cannot drive directly to the buzzer, because the
Microcontroller cannot give sufficient current to drive the buzzer for that we
need a driver transistor (BC547), which will give sufficient current to the
buzzer.Whenever a signal received to the base of the transistor through a base
resistance (1.5k) is high, the transistor comes to saturation condition i.e. ON
condition thus the buzzer comes to on condition with a audible sound.
Similarly, whenever the signal is not received to the base of the transistor, thus
the transistor is in cut-off state i.e. is in OFF state thus the buzzer does not gets
activated.

20. Circuit diagram
BUZZER DRIVER
1.5K
BC547
DATA
INPUT
BUZZER
VCC

21. Conclusion
The system is designed in the laboratory and tested in the
laboratory condition. It is observed that the system is operating
satisfactorily with a very minimum error which is quit less than the
experimental tolerance level. The design is quite stable and
economical.

22. Future expansion
This project has a vast field for expansion. The controller is designed with latest
technology of communication and control. This project is designed with constraint
of time and cost. This project can be modified and expanded in the following
fields,
-The controller can be interfaced to with sensor to send back the information to
the user regarding its initial position.
-The music generator can be replaced with multiple voice stack. So a status
message can be send back to the user.
-Multiple devices can be controlled by single command.
-A timer base control unit can be developed so that ON TIMER and OFF TIMER
can be implemented
-A SMS base protection system or security system can be combined with this
Design.

23. ------------------ Thank you --------------------