Innovative project of my Innovative idea

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DTMF BASED HOME AUTOMATION
Sri Vasavi Institute Of Engineering and Technology
(affiliated to JNTUK,Kakinada and Approved by AICTE,New Delhi)
Nandamuru,Pedana Mandal, Krishna District, Andhra Pradesh
2015-2018
By
S.L.PRASANTH

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Contents:
• Introduction
• Circuit diagram
• Components
• Working
• Advantages
• Disadvantages
• Applications
• Conclusion

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INTRODUCTION
 We use many different types of communication in control
applications to control home appliances, industrial appliances,
and other type of automation.
 There are two types of communication that is we generally use -
one is wired and other one is wireless. In wireless communication
we transmits signal wirelessly, like using radio frequency (RF)
and in wired communication in which we uses wires like copper
wire.
 In this project “DTMF Based Home Automation System” we are
going to control our home appliances wirelessly.

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 DTMF controlled home automation
project works over mobile DTMF
technology that exists in Dial tone.
 DTMF stands for Dual Tone
Multiple Frequency.
 In simple words by adding or mixing
two or more frequencies generates
DTMF tone.

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CIRCUIT DIAGRAM

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COMPONENTS
MT8870 DTMF Decoder Capacitors(22pf,0.1uf)
ULN2003 LED’s
7805 regulator 3.57Mhz crystal
5V Relay Mobile phone
Resistors(100k,330k,1k) 9v battery
Connecting wires Aux wire

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MT8870
• The MT8870D is a complete
DTMF receiver integrating both
the band split filter and digital
decoder functions. The filter
section uses switched capacitor
techniques for high and low
group filters; the decoder uses
digital counting techniques to
detect and decode all 16 DTMF
tone-pairs into a 4-bit code.

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ULN2003
• Driver Ic’s are used when
Driving a wide range of loads
and are used as relay drivers,
display drivers, line drivers
etc.
• ULN2003 is also commonly
used while driving Stepper
Motors

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7805 Voltage Regulator
• 7805 is a voltage regulator
integrated circuit.
• The voltage regulator IC
maintains the output voltage
at a constant value.

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Relay Switch
• Relay is an electromagnetic device which is used to
isolate two circuits electrically and connect them
magnetically. They are very useful devices and allow
one circuit to switch another one while they are
completely separate.
• A relay switch can be divided into two parts: input
and output. The input section has a coil which
generates magnetic field when a small voltage from
an electronic circuit is applied to it.
• In a basic relay there are three contactors: normally
open (NO), normally closed (NC) and common (COM).

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Crystal oscillator
• A crystal oscillator is an electronic oscillator
circuit that uses a piezoelectric resonator, a
crystal, as its frequency-determining element.
Crystal is the common term used in electronics
for the frequency-determining component, a
wafer of quartz crystal or ceramic with
electrodes connected to it. A more accurate
term for it is piezoelectric resonator. Crystals
are also used in other types of electronic
circuits, such as crystal filters.

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Resistors & Capacitors
• A resistor represents a given
amount of resistance in a circuit.
Resistance is a measure of how
the flow of electric current is
opposed or "resisted.“
• A capacitor represents the
amount of capacitance in a circuit.
The capacitance is the ability of a
component to store an electrical
charge.
Capacitor Symbol
Resistor Symbol

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Light-emitting diode
• A light-emitting diode (LED) is a two-lead
semiconductor light source. It is a p–n
junction diode, which emits light when
activated. When a suitable voltage is applied
to the leads, electrons are able to recombine
with electron holes within the device,
releasing energy in the form of photons. This
effect is called electroluminescence, and the
color of the light (corresponding to the
energy of the photon) is determined by the
energy band gap of the semiconductor.

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Nine-volt battery
• The nine-volt battery, or 9-volt battery, in its most
common form was introduced for the early
transistor radios. It has a rectangular prism shape
with rounded edges and a polarized snap connector
at the top. This type is commonly used in walkie
talkies, clocks and smoke detectors.
• The nine-volt battery format is commonly available
in primary carbon-zinc and alkaline chemistry, in
primary lithium iron disulfide, and in rechargeable
form in nickel-cadmium, nickel-metal hydride and
lithium-ion.

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Auxiliary wire
• A phone connector, also known as phone
jack, audio jack, headphone jack or jack plug, is
a common family of electrical connector
typically used for analog signals, primarily audio.
• It is cylindrical in shape, typically with two,
three, four and, recently, five contacts. Three-
contact versions are known as TRS connectors,
where T stands for "tip", R stands
for "ring" and S stands for "sleeve". Similarly,
two-, four- and five- contact versions are called
TS, TRRS and TRRRS connectors respectively.

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WORKING
• Here we have connected a
mobile phone using aux wire to
the DTMF decoder circuit.
• If we press any key on the
mobile phone then the
corresponding row and column
frequencies are given to DTMF
decoder.
• Here the DTMF decoder will
mix those frequencies and
generates corresponding binary
value. i.e.;

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key
Q4 Q3 Q2 Q1
1 0 0 0 1
2 0 0 1 0
3 0 0 1 1
4 0 1 0 0
5 0 1 0 1
6 0 1 1 0
7 0 1 1 1
8 1 0 0 0
9 1 0 0 1
0 1 0 1 0
* 1 0 1 1
# 1 1 0 0
Digital output

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 The DTMF decoder output is connected to driver IC.
 Here the driver IC is used to drive the relays for supplying
the constant voltage.
 Here the relays are connected to the driver IC.
 Relay is ON when the decoder output is HIGH otherwise
the relay is OFF state.
 The outputs of relays are Q1,Q2,Q3,Q4 and they are
connected to different electronic appliances like
AC,FAN,MOTOR,....... etc;
 If Q1 is 1(i.e.; HIGH) then the corresponding device is ON.
 If it is 0(i.e.; LOW) that device is OFF.
WORKING

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ADVANTAGES
 Easy to maintain and repair.
 Comparatively the operation cost is less.
 Design is efficient and low cost.
 Power consumption is low.
 Controlling electrical devices wirelessly
 Saves electricity (when we forget to switch off and go out).
 We can control appliances from any place round the globe.
 No coding is required.

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DIS ADVANTAGES
 This system is not capable of displaying the feedback status of
the devices being operated.
 This system needs a cell phone to be placed in circuit.
 Anyone who knows the phone number and can control our
electrical appliances
 Number of electrical appliances that can be controlled by this
circuit is limited.

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APPLICATIONS
 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 using 4 x16 decoder IC.

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CONCLUSION
• In these by 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.