Download Remote Control of Industrial Machines Using Mobile Phone

International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 1, January 2013)
Remote Control of Industrial Machines Using Mobile Phone
Poulastya Mukherjee1
Poulastya Mukherjee (B.Tech P-283A, Narkeldanga Main Road, Kolkata-700054)
2
Second Author Affiliation & Address
3
Third Author Affiliation & Address
Abstract— In today’s world basic requirement for a factory
to run is that it should be completely remote controlled using
PLCs and DCS. However PLCs and DCS are very costly and
often cannot be afforded by small and medium scale
industries but the requirement of remote control is still very
much present. This project attempts to fill this very gap.
A. Project outline
 A brief introduction to internal architecture of micro
controller.
 An over view of programming of micro controller.
 An overview on assembly language.
 An overview of DTMF decoder MT8870.
 An overview on interface of switches and relays.
Keywords—MT8870, ATMEGA 16, L293D, DTMF, Relay.
I. INTRODUCTION
B. Interfaces Used
In this circuit we use DTMF(dual tone multiple
frequency)tones to control the machines. DTMF tones are
generated when during a call from one phone to another
keys are pressed. Each of these tones have a specific
frequency. These frequencies are decoded using a DTMF
decoder-MT8870. The output of this circuit is be fed to the
microcontroller and processed. The output of the
microcontroller is subsequently used to turn on or off
devices via relay.
The version of DTMF used for telephone tone dialing is
known as ‘Touch-Tone’. DTMF assigns a specific
frequency to each key so that it can easily identified by the
electronic circuit. The signal generated by the DTMF
encoders a direct algebraic summation, in real time, of the
amplitudes of the two sinusoids.
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DTMF decoder interfacing
Microcontroller interfacing
Motor driver interfacing
Keypad interfacing
Switches, led and fan interfacing
C. Software Used
A cross compiler - CVAVR for compiling and linking
the code written for ATMEGA 16.
Serial communication software for downloading code to
ATMEGA 16
II. CIRCUIT DESCRIPTION
The important components of this project are a DTMF
decoder, microcontroller and relay.
A CM8870 series DTMF decoder is used here. All types
of the CM8870 series use digital counting techniques to
detect and decode all the 16 DTMF tone pairs into a 4-bit
code output. The built -in dial tone rejection circuit
eliminates the need of pre-filtering.
When the input signal are given at pins 1 (IN+) &
2(IN-), a different input configuration is recognized to be
effective, the correct 4-bit decode signal of the DTMF tone
is transferred to pin 11 through pin 14 outputs.
Figure 1:- Basic project outline
648
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 1, January 2013)
Figure 2:-Main Circuit Diagram
Before the DTMF here we used two zener diode to
regulate the input voltage and two capacitor to protect the
circuit from unwanted signal. Here in this circuit DTMF
pin 17 and pin 16 are shorted together by a diode. The
purpose of this diode to increase the output holding time.
The pin 11 to pin 14 of DTMF decoder are connected to
the pins of one inverter 74LS04 to invert the output and
then the output of the inverter connected to the pins of
ATMEGA 16 microcontroller( pin37 to pin 40).
The output of a microcontroller is approximately 5V
which is insufficient to drive a relay. So we have used a
motor driver L293D through which we can get a voltage of
12V which can drive a relay.
Outputs from pins 14 to pin 21 of the microcontroller are
fed to the pins 2 and 10 while 7 and 15 are grounded. The
output from pins 3,6,11 and 14 are given as inputs to the
relay. Which is subsequently fed to the final output devices.
The version of DTMF used for telephone tone dialing is
known by the trademarked term Touch-Tone and is
standardized by ITU-T Recommendation Q.23. It is also
known in the UK as MF4. Other multi-frequency systems
are used for signaling internal to the telephone network.
DTMF signaling is used for telephone signaling over the
line in the voice-frequency band to the call switching
center. The version of DTMF used for telephone tone
dialing is known as TOUCH-TONE.
DTMF assigns a specific frequency to each key so that it
can easily identified by the electronic circuit. The signal
generated by the DTMF encoder is a direct algebraic
summation, in real time, of the amplitudes of the two sine /
cosine waves.The MT8870 DTMF decoder decodes this
DTMF tone into its equivalent binary codes and then sends
to the microcontroller. The microcontroller is designed to
take decisions for any given input to generate a specific
output. Thus the mobile phone acts as a remote control.
The table below gives the list of higher and lower group
of frequencies, the combination of which gives the
respective digits. The decoder converts these decimal digits
to 4bit binary output given as D0, D1, D2, D3 where D0 is
LSB and D3 is MSB
A. Main Technology Used
The main technology we have used is DTMF(Dual Tone
Multiple Frequency).
Dual-tone multi frequency signaling is used for
telecommunication signaling over analog telephone lines in
the voice frequency band between telephone handsets and
other communications devices and the switching center.
649
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 1, January 2013)
TABLE I
DTMF DATA OUTPUT
Low
Group (Hz)
697
697
697
770
770
770
852
852
852
941
941
941
697
770
852
941
High
Group
(Hz)
1209
1336
1477
1209
1336
1477
1209
1336
1477
1336
1209
1477
1633
1633
1633
1633
Digit
OE
D3
D2
D1
D0
1
2
3
4
5
6
7
8
9
0
*
#
A
B
C
D
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
B. Devices Used
2) ATMEGA 16 Microcontroller:
The main brain of this project is the ATMEGA 16
microcontroller. It is a very versatile device using RISC
architecture. It receives output from the MT8870 chip via
the NOT gate. It receives a 4bit input and according to the
combination of input bits it gives out a 4bit output.
The input comes to pins 37-40 of Port A. The output is
from pins 14-17 of Port D.
The programming of this device was done by CV AVR
software which supports coding in C language.
1) Dtmf Decoder:
The M-8870 decoder uses a digital counting technique to
determine the frequencies of the limited tones and to verify
that they correspond to standard DTMF frequencies. A
complex averaging algorithm is used to protect against tone
simulation by extraneous signals (such as voice) while
tolerating small frequency variations.
The algorithm ensures an optimum combination of
immunity to talk-off and tolerance to interfering signals
(third tones) and noise. When the detector recognizes the
simultaneous presence of two valid tones. (known as signal
condition), it raises the Early Steering flag (ESt). Any
subsequent loss of signal condition will cause ESt to fall.
Figure 3:- MT 8870 DTMF decoder
Figure 4:- ATMEGA 16 microcontroller
650
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 1, January 2013)
3) L293D Motor Driver:
As mentioned earlier that microcontroller output is
incapable of driving a relay, we have used L293D motor
driver to provide a 12V output which can sufficiently drive
a relay. We have kept the enable pins high and in the input
pair 1 and 2 given input only to input 1 or pin2 and have
grounded the input 2 or pin 7, so that it acts as a switch and
gives a 12V output only when it receives an input at pin no.
2.
III. BASIC WORKING PRINCIPLE
When we press any key on the mobile phone a dtmf tone
is generated which is transmitted to the DTMF decoder
using an earphone. Upon receiving the signal the MT8870
decoder converts it to a 4bit binary number. This number is
sent to a NOT gate(a negative logic design has been used in
this project) and then it is subsequently sent to the
microcontroller. The microcontroller gives out a output
based on the input, which acts as a input to the motor
driver. The output from the motor driver then turns on the
relay and the subsequent output device.
IV. FURTHER APPLICATIONS
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Figure 2:- L293D Motor Driver
Long range robotic devices
Pump station supervising and irrigation
Home automation system
Un-manned equipment monitoring
REFERENCES
The heading of the References section must not be
numbered. All reference items must be in 8 pt font. Please
use Regular and Italic styles to distinguish different fields
as shown in the References section. Number the reference
items consecutively in square brackets (e.g. [1]).
4) Relay:
The output from the motor driver is given to the relay.
When the relay turns on the final elements like heater,
cooling fan or other industrial equipments can be turned on
or off.
[1]
P.Raghavendra Prasad and K.Susram Rahul for publication of their
project paper on Cell-phone Operated Land-rover (Microcontroller
based) on www.efymag.com
[2]
Table and chip images from documentation of MT8870 DTMF
Decoder chip from http://www.wulfden.org/TheShoppe.shtml
[3]
www.wikipedia.org for papers and review works on related projects
[4]
Demo project paper published on [email protected]
[5]
Documentation of AVR development tools by [email protected]
Tavel, P. 2007 Modeling and Simulation Design. AK Peters Ltd.
[6]
ATmega16 datasheet by ATMEL
Figure 3:- A relay
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