DTMF technology

1. Project presentation on
Gsm controlled robot with obstacle avoidance using ir sensors
Submitted by:
V.Rahul T.Sneha O.Srinath

2. CONTENTS
• Introduction
• Basic blockdiagramof project
• Schematicdiagram
• Technology used
• Componentsused
• Working mechanism
• Softwareused
• Algorithm
• Advantages anddisadvantages
• Applications
• Futurescope
• Conclusion
• References

3. INTRODUCTION
• In this project, the robot is controlled by a mobile phone that
makes a call to the mobile phone attachedto the robot.
• WHAT IS DTMF?
• “Dual Tone Multiple Frequency”
• The received tone is processed by the microcontrollerwiththe help
of DTMF decoder.
• The microcontroller then transmits the signal to the motor driver
ICs to operate the motors & our robot starts moving.

4. BASIC BLOCK DIAGRAM OF
THE PROJECT
TELEPHONE
DTMF DECODER
POWER SUPPLY
ATMEGA8
MICRO
CONTROLLER
IR SENSOR
L293D IC
MOTOR
MOTOR

5. SCHEMATIC DIAGRAM

6. TECHNOLOGY USED
• DTMF  Dual Tone Multiple Frequency
• The versionof DTMFused for telephonedialing is knownas touchtone.
• DTMFassignsa specificfrequency (consisting of two separate tones) to eachkey’sthatit
can easilybe identifiedby the electroniccircuit.
• DTMF assigns a unique‘sound’ to each key.
• Keysare arrangedin a matrix of 4 columns and 4 rows.

7. • The signal generated by the DTMF encoder is the direct algebraic
submission, in real time of the amplitudes of two sine (cosine)
waves of different frequencies, i.e., pressing5 will send a tone made
by adding1336 Hz and 770 Hz to the otherend of the mobile.

8. COMPONENTS USED
• ATMEGA8 MC DEVELOPMENT BOARD
• DTMF DECODER –HT9170D IC
• IR SENSOR-LM358 IC
• MOTOR DRIVING IC-L293D IC
• GSM MOBILES
• MOTORS

9. WORKING MECHANISM
• Controlof robot involves4 different phases:
a) Perception
b) Processing
c) Action
d) Detection
1.PERCEPTION
• First part is to make a call to the mobilephonewhichis attached to the robot.
• Next partis the decoding of DTMFtone generatedby pressinga key in calling phone.
• Audiosignal output fromreceivingphoneis fedto DTMFdecoderchip.
• DecoderchipconvertsDTMFtoneintobinary codesto be fedto microcontroller.
• HT9170D IC usedas DTMFdecoder in our project.

10. TRUTH TABLE FOR DTMF
DECODER

11. 2. PROCESSING
• Afterperceptionstage,microcontrollerprocessesthebinary codesit receives.
• Microcontrollerispre-programmedin “EmbeddedC” to performspecifictaskaccordingto inputbits.
• Atmel’sATmega8is usedfor processing
3. ACTION
• Finalstageisrotationof motorsbasedon inputgivenby the microcontroller.
• Inthisprojectwehaveused5 keysforcontrollingtherobotandtheirdualtonesare
Key's on mobile Operation Low frequency High frequency
1 "FORWARD" 697 1209
2 "BACKWARD" 697 1336
3 "TURN RIGHT" 697 1477
4 "TURN LEFT" 770 1209
5 "STOP" 770 1336

12. 4. DETECTION
• For obstacledetection,a IR transmitterand receiveris used
• When the obstaclecome near the robot,the IR transmitterwilltransmitthe IR rayson the objectand the
objectwill reflect the IR raysto the IR receiver.
• The IR receiverwill receivethe IR raysand it will activatethe microcontrollerand performitsspecified
task.
• In thisproject whenkey "1" is pressedthe robotmovesin forwarddirectionand while movingin the
forwarddirectionif the robot has come acrossan obstaclethenthe robot stops and we can control the
robotwith othercommands

13. SOFTWARE USED
• The code is writtenin ‘EmbeddedC’ language
• Hexcode for Atmega8 is generated by using ‘ATMEL STUDIO6.0 ‘
• The next software we used is ‘PROTEUS 7.7 PROFESSIONAL’ for circuit schematic
designand layout design.
• Finally we have used ‘PROG ISP’ software for dumping the hex code generated into
the hardware

14. ALGORITHM
• STEP 1: START
• STEP 2: DECLARE VARIABLES
• STEP 3: SET PORT B AS I/P PORT
• STEP 4: SET PORT D AS I/P PORT
• STEP 5: SET PORT C AS O/P PORT
• STEP 6: ACCEPT INPUT
• IF I/P IS 0X05 THEN MOVE MOTOR IN FORWARD DIRECTION
• IF I/P IS 0X0A THEN MOVE MOTOR IN BACKWARD DIRECTION
• IF I/P IS 0X01 THEN MOVE MOTOR TO RIGHT
• IF I/P IS 0X04 THEN MOVE MOTOR TO LEFT
• IF I/P IS 0X00 THEN STOP MOVING MOTOR
• STEP 7: STOP

15. ADVANTAGES
• This wirelessdevice has noboundationof range andcan be controlledas far as network
of cell phone
• Usedto control house holdappliances
• In industries and factories for remotesensing
• Using 3g technology we canspy a place
DISADVANTAGES
• Not at all usefulif we do not have network
• Call charges
• Headphoneswhich wouldbe damaged very frequently

16. APPLICATIONS
• ScientificUse
• Military and Law Enforcement
• Search and Rescue
• Forest Conservation

17. FUTURE SCOPE
• Password Protection
• Alarm-Phone Dialer
• Adding a Camera
• Adding a microphone

18. CONCLUSION
• This project hadthe goal of manipulating different parts of the robot to make it
react accordingto our desire.
• Conventional radio frequency robot control techniques haddisadvantages like,
limitedworkingrange,and limitedfrequencyandbandwidthranges, andwith
less operational control.
• In this project usingmobile phonefor robotic control hadwide working ranges
with highcontrol, less interference with intense accessibility.
• Project can also be subjected to standardizationand hencehas a good future
scope