Transcript Project Presentation

BY:
SHEETAL DADLANI
RONAK KHARA
SHANTANU KHARE
RINKU ROHIRA
PROJECT GUIDED BY:
MRS. ARCHANA SINGHI MAM
HEAD OF DEPARTMENT:
MRS. SUNITA SHARMA MAM
ABSTRACT
DTMF controlled robot is proposed that can move in any direction on a
plain surface which can be controlled by using a GSM or CDMA mobile
phone where the medium of communication is DTMF tones.
The robot can revolutionize the transport system of the robots and the way
we operate it by a small embedded system device.
The robot is an Omni-directional robot which can be manoeuvred by a cell
phone and can be used as a compact, quiet, mobile, and durable transport
vehicle in cramped environments and in loading and unloading stations.
The main focus was laid on the type of movement the robot makes on the
spot and its control using a cell phone.
INTRODUCTION
Conventionally, Wireless-controlled robots use RF circuits, which have
the drawbacks of limited working range, limited frequency range and the
limited control. Use of a mobile phone for robotic control can overcome
these limitations. It provides the advantage of robust control, working
range as large as the coverage area of the service provider, no interference
with other controllers and up to twelve controllers.
Although the appearance and the capabilities of robots vary vastly, all
robots share the feature of a mechanical, movable structure under some
form of control. The Control of robot involves three distinct phases:
perception, processing and action.
Generally, the preceptors are sensors mounted on the robot, processing is
done by the on-board microcontroller or processor, and the task is
performed using motors or with some other actuators.
BLOCK DIAGRAM
WORKING OF BLOCK DIAGRAM
In this project the robot, is controlled by a mobile phone that makes call to
the mobile phone attached to the robot. In the course of the call, if any button
is pressed, a tone corresponding to the button pressed is heard at the other
end of the call. This tone is called DTMF tone. The robot receives this
DTMF tone with the help of phone stacked in the robot.
The received tone is processed by the atmega16 microcontroller with the
help of DTMF decoder MT8870. The decoder decodes the DTMF tone in to
its equivalent binary digit and this binary number is send to the
microcontroller. The microcontroller is preprogrammed to take a decision for
any give input and outputs its decision to motor drivers in order to drive the
motors for forward or backward motion or a turn.
The mobile that makes a call to the mobile phone stacked in the robot acts
as a remote. So this simple robotic project does not require the construction
of receiver and transmitter units.
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 dialing is known as ‘Touch –Tone’.
DTMF assigns a specific frequency (consisting of two separate tones) to
each key s that it can easily be identified by the electronic circuit. The signal
generated by the DTMF encoder is the direct al-gebraic submission, in real
time of the amplitudes of two sine (cosine) waves of different frequencies,
i.e., pressing ‘5’ will send a tone made by adding 1336Hz and 770Hz to the
other end of the mobile. The tones and assignments in a DTMF system
shown below
DTMF BASICS
DTMF is a tone composed of two sine waves of given frequencies. Individual
frequencies are chosen so that it is quite easy to design frequency filters, and so that
they can easily pass through telephone lines (where the maximum guaranteed bandwith
extends from about 300 Hz to 3.5 kHz). DTMF was not intended for data transfer; it is
designed for control signals only.
DTMF USAGE
DTMF is the basis for voice communications control. Modern telephony uses DTMF to
dial numbers, configure telephone exchanges, and so on. It is used to transfer
information between radio transceivers, in voice mail applications, etc.
HOW TO TRANSMIT DTMF
Most often, dedicated telephony circuits are used to generate DTMF. On the other hand,
a microprocessor can do it, too. Just connect a RC filter to two output pins, and generate
correct tones via software.
1209
Hz
FREQUENCY TABLE
This table resembles a matrix keyboard.
The X and Y coordinates of each code give
the two frequencies that the code is
composed of. There are 16 codes;
however, common DTMF dialers use only
12 of them. The "A" through "D" are
"system" codes. Most end users won't need
any of those; they are used to configure
phone exchanges or to perform other
special functions
697
Hz
770
Hz
852
Hz
941
Hz
1336
Hz
1477
Hz
1633
Hz
1
2
3
A
4
5
6
B
7
8
9
C
*
0
#
D
HOW TO DECODE DTMF:
It is not easy to detect and recognize DTMF with satisfactory precision. Often,
dedicated integrated circuits are used, although a functional solution for DTMF
transmission and receiving by a microprocessor .It is rather complicated, so it is used
only marginally. Most often, a MT 8870 or compatible circuit would be used.
SERVO MOTORS
Specialized motors that can move their shaft to a specific position
DC motors can only move in one direction
“Servo”
• capability to self-regulate its behavior, i.e., to measure its own position and
compensate for external loads when responding to a control signal
Hobby radio control applications:
• Radio-controlled cars: front wheel steering
• RC airplanes: control the orientation of the wing flaps and rudders
Servo motors are built from DC motors by adding:
• Gear reduction
• Position sensor for the motor shaft
• Electronics that tell the motor how much to turn and in what direction
Movement limitations
• Shaft travel is restricted to 180 degrees
• Sufficient for most applications
OPERATION OF SERVO MOTORS
The input to the servo motor is desired position of the output shaft.
This signal is compared with a feedback signal indicating the actual
position of the shaft (as measured by position sensor).
An “error signal” is generated that directs the motor drive circuit to power
the motor
The servo’s gear reduction drives the final output.
CONTROL OF SERVO MOTORS
Input is given as an electronic signal, as a series of pulses
• length of the pulse is interpreted to signify control value:
pulse-width modulation
Width of pulse must be accurate (s)
• Otherwise the motor could jitter or go over its
mechanical limits
The duration between pulses is not as important (ms
variations)
• When no pulse arrives the motor stops
Three sample waveforms
for controlling a servo
motor
DEGREES OF FREEDOM (DOF)
DOF: any direction in which motion can be made
The number of a robot’s DOFs influences its performance of a task
Most simple actuators (motors) control a single DOF
• Left-right, up-down, in-out
Wheels for example have only one degree of freedom
Robotic arms have many more DOFs
USES OF EFFECTORS
Locomotion
• Moving a robot around
Manipulation
• Moving objects around
Effectors for locomotion
• Legs: walking/crawling/climbing/jumping/hopping
• Wheels: rolling
• Arms: swinging/crawling/climbing
• Flippers: swimming
Most robots use wheels for locomotion
STABILITY
Robots need to be stable to get their job done
Stability can be
• Static: the robot can stand still without falling over
• Dynamic: the body must actively balance or move to remain stable
Static stability is achieved through the mechanical design of the robot
Dynamic stability is achieved through control
STATICALLY STABLE WALKING
If the robot can walk while staying balanced at all times it is statically
stable walking
 There need to be enough legs to keep the robot stable
• Three legged robots are not statically stable
• Four legged robots can only lift one leg at a time
• Slow walking pace, energy inefficient
• Six legs are very popular (both in nature and in robotics) and
allow for very stable walking
GETTING THERE
Robot locomotion is necessary for
• Getting the robot to a particular location
• Having the robot follow a particular path
Path following is more difficult than getting to a destination
Some paths are impossible to follow
• This is due to non-holonomicity
Some paths can be followed, but only with discontinuous velocity (stop,
turn, go)
• Parallel parking
TYPES OF JOINTS
There are two main types of joints
Rotary
• Rotational movement around a fixed axis
Prismatic
• Linear movement
ANOTHER BASICS INVOLVED
DC Motors
Motor Efficiency
Operating Voltage
Operating/Stall Current
Torque
Stall Torque
Power of a Motor
How Fast do Motors Turn?
Gearing
Meshing Gears
Gearing Effect on Speed
Torque – Speed Tradeoff
LIST OFCOMPONENTS
SR. No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Description
Transformer 12-0-12V,750mA
Diode 1N4007
Capacitor1000uF,25V
Voltage regulator IC 7805
Capacitor 1uF
LED
Resistors
Disc capacitors
IC Base
PCB
Wires
Solder wire
Cabinet
Mains cord
Transistor BC548
FUTURE SCOPE
IR Sensors
• IR sensors can be used to automatically detect & avoid obstacles if the robot
goes beyond line of sight. This avoids damage to the vehicle if we are
maneuvering it from a distant place.
Password Protection
• Project can be modified in order to password protect the robot so that it can be
operated only if correct password is entered. Either cell phone should be
password protected or necessary modification should be made in the assembly
language code. This introduces conditioned access & increases security to a
great extent.
Alarm Phone Dialer
• By replacing DTMF Decoder IC CM8870 by a 'DTMF Transceiver IC’
CM8880, DTMF tones can be generated from the robot. So, a project called
'Alarm Phone Dialer' can be built which will generate necessary alarms for
something that is desired to be monitored (usually by triggering a relay). For
example, a high water alarm, low temperature alarm, opening of back
window, garage door, etc.
• When the system is activated it will call a number of programmed numbers
to let the user know the alarm has been activated. This would be great to get
alerts of alarm conditions from home when user is at work.
Adding a Camera
• If the current project is interfaced with a camera (e.g. a Webcam) robot can
be driven beyond line-of-sight & range becomes practically unlimited as GSM
networks have a very large range.
APPLICATIONS
Scientific
• Remote control vehicles have various scientific uses including hazardous
environments, working in the deep ocean , and space exploration. The majority
of the probes to the other planets in our solar system have been remote control
vehicles, although some of the more recent ones were partially autonomous. The
sophistication of these devices has fueled greater debate on the need for manned
spaceflight and exploration.
Military and Law Enforcement
• Military usage of remotely controlled military vehicles dates back to the first
half of 20th century. Soviet Red Army used remotely controlled Teletanks during
1930s in the Winter War and early stage of World War II.
Search and Rescue
• UAVs will likely play an increased role in search and rescue in the United
States. This was demonstrated by the successful use of UAVs during the 2008
hurricanes that struck Louisiana and Texas.
Recreation and Hobby
• See Radio-controlled model. Small scale remote control vehicles have long
been popular among hobbyists. These remote controlled vehicles span a wide
range in terms of price and sophistication. There are many types of radio
controlled vehicles. These include on-road cars, off-road trucks, boats,
airplanes, and even helicopters. The "robots" now popular in television
shows such as Robot Wars, are a recent extension of this hobby (these
vehicles do not meet the classical definition of a robot; they are remotely
controlled by a human).
ADVANTAGES
DTMF’s technology is simple, low cost, as well as its already popular
status in the telephone industry of today.
In the networks there are large number of nodes that are very simple and
act merely as relay stations.
In healthcare (hospital and home environments), a robot that is capable of
sending acoustic commands to turn on/off devices such as light switch or
closing door while letting the user know that the process is taking place will
be very helpful in allowing the user to feel more comfortable around robots.
CONCLUSION
This paper has described the design and implementation of experiments to test
the feasibility of using the Dual Tone Multi-Frequency encoding scheme as a
method for communicating simple messages.