
ØVoice
communication
ØData
communication
ØControlling
devices
Components required:-
Ic
741 Op Amp
IC
7805 Voltage Regulator
Diode 4004 Pn diodes
IC
91214 DTMF encoder
IC
7447- Seven Segment Display driver IC
Seven Segment Dispaly
Ic8870 DTMF decoder
9
v Transformer 50mA
IR
Singal mode
Resistances- 10k,1k,4.7k,220k
Capacitors- 0.1microfarad,00.1 microfarad,1000µf,470µf
Cupper clad board
Fecl3 for PCB design
Software Required:-
Window os
OrCAD
MS
word
Introduction:-
In
this project we will learn about how to use IR for communication
purpose. IR need not to introduce. Everybody although he/she may be
from any field know about Optical. IR as we know a reliable, low
cost, flexible, large bandwidth communication medium. In this
communication system we will use condenser mic for txer . Condenser
mic is most sensitive mic. Its generally available and low cost.
In
this circuit voltage amplifier will amplify the mic signal then
signal will be amplified by power amplified.LED will transmit the
rxed voice signal via IR. On rxer side detector will detect the
signal then it will transfer the signal to special amplifier then
the signal will be input for speaker. We will use DPDT switch for
selecting voice and data signal
In
data transmission we will transfer the data using DTMF technology.
DTMF is dual tone multi frequency technology. In this we will use
dtmf encoder with keyboard for data generation purpose. On the
receiver side we will use dtmf decoder IC 8870 for it. Output of it
will be the input od seven segment display driver IC. Output of
Seven segment decoder IC will be the input of Seven segment display.
We will common anode seven segment display. Seven will show the no
entered with kryboard. When we will give signal on mic then speaker
will give voice signal output. We will make +5v power supply for
encoder & decoder ICs & +9v for amplifier circuits. In this project
will study about voice and data transmission.
In
this project we will learn about how to use IR for communication
purpose. IR need not to introduce. Everybody although he/she may be
from any field know about Optical. IR as we know a reliable, low
cost, flexible, large bandwidth communication medium.
In
this project we can control any electrical appliances through DTMF
dialing circuit for remote purpose . When we want to control any
electrical appliances through DTMF dialing circuit. Now again we
press the switch on/off code to on/off any electrical appliances.
With the help of this code unit is on and base unit give a
acknowledge pulse for on and off separately.
DTMF Encoder Circuit:-
in
this circuit we will use IC91214 for no of devices. We will add
keyboard with this IC. Ethis IC have option to generate 16 different
pulses with different frequencies. These dual tone multi frequencies
can be decoded at receiver side with IC8870 . these IC are esily
available in market. We will use LASER for data transmission.
1.
DTMF
DECODER
In
dtmf decoder circuit we use ic 8870 ic. IC 8870 is a dtmf decoder ic.
IC 8870 converts the dual tones to corresponding binary outputs.
DTMF SIGNALLING.
Ac register signaling is used in dtmf telephones, here tones rather
than make/break pulse are used fro dialing, each dialed digit is
uniquely represented by a pair of sine waves tones. These tones (
one from low group for row and another from high group fro column)
are sent to the exchange when a digit is dialed by pushing the key,
these tone lies within the speech band of 300 to 3400 hz, and are
chosen so as to minimize the possibility of any valid frequency pair
existing in normal speech simultaneously. Actually, this minimisator
is made possible by forming pairs with one tone from the higher
group and the other from the lower of frequencies. A valid dtmf
signal is the sum of two tones, one from a lower group ( 697-940
Hz) and the other from a a higher group ( 1209-1663 Hz). Each group
contains four individual tones. This scheme allows 10 unique
combinations. Ten of these code represent digits 1 through 9 and 0.
. tones in DTMF dialing are so chose that none of the tones is
harmonic of are other tone. Therefore is no change of distortion
caused by harmonics. Each tone is sent as along as the key remains
pressed. The dtmf signal contains only one component from each of
the high and low group. This significaly simplifies decoding because
the composite dtmf signal may be separated with band pass filters
into single frequency components, each of which may be handled
individually.
First ic of this section is ic 74154. IC 74154 is bcd to decimal
decoder. 74154 is active low ic. Pin no 20,21,22,23 is connected to
dtmf decoder ic.
Pin
no 18 and 19 of this ic is connected to the collector of one npn
transistor Base of the npn transistor is connected to the pin no 15
of the ic 8870. When dtmf decoder decode the signal at that time pin
no 15 is on for a time and acknowledge the signal. This signal is
fed to the base of NPN transistor through 1 kohm resistor. When
this signal is coming then 74154 is on and gives a output.
Then
output of 74154 is active low. We will use IC 74ls 74 or
transistors to invert the active low output. After that we will use
flip flop & SCRs or relays to control & to give 220v Ac to devices
for switching purposes.
8 9 10 11
12
PIN DESCRIPTION
IC
74154 is a BCD to Decimal converter. This IC is a 24 pin IC. Pin
no.20,21, 22,23 are the BCD input pins of this IC,pin no.
2,3,4,5,6,7,8,9,10,11, are the output pins, pin no.24 is connected
to the positive 5 volt supply and pin no.12 is the negative supply
pin. Pin no. 18 and pin no. 19 of this IC is enable pin. If the data
available on the pin no. 19 is negative then output is negative for
a time. The negative pulse is given by the NPN transistor collector
point. IC 74154 is a special package may be used to provide a 1 low
output out of 16 outputs or may be used to send input data to one
selected output of 16, the remaining 15 staying high.
Substitute IC:
No other
substitute easily available
PIN DESCRIPTION
IC
4049 is a hex inverter IC. Pin no. is connected to the positive
supply. Pin no. 7 is connected to negative supply. Pin no.
3,5,7,9,11 are the inputs of the IC and pin no. 2,4,6,10,12 are the
input pins of this IC. Since the output of IC 74154 are low hence IC
4049 is used to invert the output of IC 74154, ie , to convert the
low output of the decoder IC into high output
Substitute IC:
7404
IC 8870
PROCREDURE TO MAKE
PROJECT:-
- IDEA OF PROJECT
In this stage student select the topic of the project of the
project. It’s the main stage of project work.its the area where
talented students shows their innovative ideas. Innovative students
make project with a new idea then others. We selected this project
because we want to do something in with our own hands. We use main
electronics components uded in the industry. First of all we
selected the GSM based project. Then we drop idea because there was
little bit practical electronics to learn and mobile companies
already providing those facility.
- STUDY MATERIAL AND
CIRCUIT DIAGRAM
In this section we collected the study material. We searches about
our project on google.com,www.yahoo.com,www.msn.com
TESTING OF MAIN CIRCUIT-
Then we collect the components of project. It was not a easy task.
Because no shop in our area have all the components. Then after
collection of components we test the circuit on bread board - step
by step. Because we want to sure about the circuit. We checked it in
different steps beacuuse it was a big project and was not possible
to check it in a single step.
- PCB DESIGNING
- After Testing of circuite sure about the circuit.
First of all we designed the layout of PCB .
Then we made a screen .
After that we mark the layout on clad board with the help of paint
and screen.
Then we dip that painted PCB in Ferric chloride solution.
After that we drill holes in PCB.
Then we washed PCB with Isopropyl solution.
- COMPONENT MOUNTING-
We kept the hole size from 0.8mm yo 1 mm for leads of components.
Then we insert components according ton their pitches.
- SODERING-
Afgter mounting components we solder the components ane by one. We
kept the temperature of iron at 250 degree to 400 degree. Because
above this temperature it can damage to component. We used general
iron available in the market of siron company. Its temperature was
nearly 350 degree acc to company specifications. We used
soldering wire of 22 gauge with flux inbuilt.
- FINAL TESTING-
After that we test the circuit step by step . and insert the ICs
after testing the one portion of the circuit an then after other
step by step. Its was tough work we tested voltage across the
compents with erepect to ground. And current in series.
- TROUBLSHOOTING-
Then we tried to troubleshoot the errors in the project.
reduce the ripple factor of power supply.
Notes by
Innovative project solutions
Sco-54,new grain market
Ludhiana
www.ludhianaprojects.com
Applications:-
Ø
Networking
between Computers.
Ø
Because of
large bandwidth used for telephone,tv network & internet comm..
Ø
Communication
between Buildings
Ø
For sensing
purpose- its use as a senser
Ø
For Security
purposes- To protect house or lockers
Ø
For Military
equipments- Because it’s a secure data transmission syatem
Ø
For Medical
machines- used as a sensing device
Ø
For
lightening purpose in decoration
Bibliography:
www.optoprojects.com/optical.doc
www.electrooptical.com/sensor.pdf
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