2. To design a project “Home Automation Control
System Using DTMF” to control Electrical devices using
mobile phone.
Aim Of The Project
3. As technology advanced man was able to control everything from one
place.
Now-a-Days Automation is playing an important role in each and
Every field such as Industrial, Home, Rural and Agricultural Areas.
Usually we used to control the industrial equipment's by manual
operation, which increases the human effort and maintenance cost.
In order to overcome this problem, the system is designed to control
devices at remote place.
To control the devices from remote place we are using a DTMF(Dual
Tone Multi Frequency) technique.
Introduction
6. Call to phone which is connected to project. Receiver phone is set as
auto answer mode i.e. call is received automatically after some time.
When we press keys in calling cell Phone when call is in progress,
the other person will hear some tones with respect to keys pressed.
These tones are based on the DTMF technology.
And Just connect your cell phone headset (headphone) jack to the
mobile phone.
The tones produced by the mobile keypad which have some
frequency.
DTMF Decoder converts the desired frequency into analog signals
and gives to PIC microcontroller.
Working
7. The microcontroller is used for switching the load equipment
according to the frequency received by the DTMF receiver by using a
combination of Relays.
The working of project is when we press 1 in calling phone then the
frequency is send from received phone to DTMF decoder IC and
decode the incoming frequency and give it microcontroller in the
binary code.
For key 1 is pressed device 1 is on and for key 2 is pressed device 1 is
off, same working follow as remaining devices.
8. The input to the circuit is applied from the regulated
power supply, i.e. 240V A.C. is converted into 5V pure D.C.
And given to the circuit.
components of power supply
Power Supply
9. The purpose of DTMF decoding is to detect sinusoidal signals in the
presence of noise and the DTMF decoder IC interfaces with a
microcontroller.
DTMF Decoder consists of MT8870 IC, it detects the number or
code represented by DTMF jack, through the inspection of the two
transmitted frequencies.
DTMF Decoder
10. PIN DIAGRAM OF DTMF DECODER IC
Fig. Pin Diagram of DTMF Decoder IC
11. DTMF (Dual tone multi
frequency) as the name suggests
uses a combination of two sine
wave tones to represent a key.
These tones are called row and
column frequencies as they
correspond to the layout of a
telephone keypad.
DTMF MODULE:
12. PIC MICROCONTROLLER:
A microcontroller is a single chip
that contains the processor (the
CPU), non-volatile memory for the
program (ROM or flash), volatile
memory for input and output
(RAM), a clock and an I/O control
unit.
Microcontroller is also called as
“computer on a chip”.
14. Description
PIC microcontroller are developed by microchip
technology.
PIC 18F4520 belongs to a 8-bit microcontroller of RISC
(Reduced Instruction Set Computing) architecture.
RISC (Reduced Instruction Set Computing) as the name
says has less number of instructions.
15. Key Features of PIC 18F4520
High performance 8-bit microcontroller
75-powerful instructions ; most single clock cycle execution
32*8 general purpose working registers
32Kbytes flash program memory, 256 Bytes EPROM, 1536byte
internal SRAM
5 i/o port
13-channel, 10-bit ADC
36 programmable i/o lines
Operating voltages 2.0-5.5V
Operating speed DC-40 MHz
16. Relay Driver IC
The eight NPN Darlington connected transistors in this family of array
are ideally suited for interfacing between low logic level digital
circuitry (such as TTL, PMOS/NMOS) and the higher current/voltage
requirements of lamps, relays, printer hammers or other similar loads
for abroad range of computer, industrial, and consumer applications.
All devices feature open–collector outputs and freewheeling clamp
diodes for transient suppression. The ULN2803 is designed to be
compatible with standard TTL families while the ULN2804 is
optimized for 6 to 15 volt high level MTOS or PMOS.
17. Fig. Pin Diagram of ULN2803 Relay Driver IC
PIN Connection OF ULN2803A
18. The relay takes advantage of the fact that when electricity
flows through a coil, it becomes an electromagnet.
The electromagnetic coil attracts a steel plate, which is
attached to a switch. So the switch's motion (ON and OFF) is
controlled by the current flowing to the coil, or not,
respectively.
Relay:
19. LCD is used in a project to
visualize the output of the
application. We have used 16x2
LCD which indicates 16
columns and 2 rows. So, we can
write 16 characters in each line.
So, total 32 characters we can
display on 16x2 LCD.
Liquid Crystal Display:
Fig. Pin Discription
20. APPLICATION
This system can be used in industrial applications.
This system can be employed in houses, where people
often forget to switch off electrical appliances.
This system can be used to control AC’s to set the room
temperature when we are outside.
We can extend this circuit to control many electrical
devices with some modifications.
21. Quick response is achieved.
Construction is easy.
Easy to maintain and repair.
Comparatively the operation cost is less.
Design is efficient and low cost.
Power consumption is low.
We can Control electrical devices wirelessly.
It Saves electricity (when we forget to switch off and go out).
We can control appliances from any place round the globe.
ADVANTAGES
22. This project can be further enhanced to be high voltage ac
applications by changing the rating of the Relay
We can control and monitor the high speed induction motors as
well as synchronous motors. This can be done in an economical
way.
In this project in future we can add a multimedia camera to see
what is going inside the home by sitting in office or somewhere.
Future Scope
23. CONCLUSION
In these my making these the circuit as the device
is connected to a corresponding circuit, its gets activated as
soon as the call is made to the circuit in which mobile or
equivalent GSM module is present to perform a specific
operation as per the relay device is connected. In these as
the keypad has12 different key, it can perform 12 distinct
operation as per connected to a relay.
