DTMF based Robot

DTMF Based Mobile Robot

DTMF Mobile ROBO is a machine that can be controlled with a mobile.  In this  project,  the  robot  is  controlled  by  a  mobile phone  that  makes a  call  to  the  mobile  phone  attached  to  the robot.  In  the  course  of  a  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 “Dual Tone Multiple-Frequency” (DTMF) tone.  The  robot  perceives  this  DTMF  tone  with  the help  of  the  phone stacked on  the  robot.  The  received  tone  is  processed  by  the  microcontroller  with  the  help  of  DTMF decoder.  The microcontroller  then  transmits  the  signal  to  the motor  driver  ICs  to  operate the  motors &  our  robot  starts moving .

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  controls. 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 DTMF based Mobile Robo
Block Diagram DTMF based Mobile Robo

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 control corresponding  to the  button pressed  is  heard  at  the  other  end  of  the  call.  This  tone  is  called  dual  tone  multi  frequency  tone  (DTMF)  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 algebraic 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  1336  Hz  and  770  Hz  to  the  other end of the mobile.  The important components of this robot are DTMF decoder, Microcontroller and motor driver.  An MT8870 series DTMF decoder is used here. All types of the mt8870  series  use  digital  counting  techniques  to  detect  and   decode  all  the  sixteen  DTMF  tone  pairs  in  to  a  four  bit  code  output.  The built -in dial tone rejection circuit eliminated the need for pre- filtering.


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