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ULTRASONIC RANGE FINDER - eCES

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									ULTRASONIC RANGE FINDER



        AMITHASH .E. PRASAD
        ARUNDATHI .B.S.
        BHUVANESHWARI .G
        SUSHMA .M
AIM OF THE PROJECT


NON CONTACT MEASUREMENT OF

DISTANCE OF AN OBJECT USING

        ULTRASOUND
    OBJECTIVES OF THE PROJECT


To design a handy device for non-contact
 measurement of distance.
For measurement of shorter distances only.
Using a microcontroller for better
 understanding of its functioning.
Less cost manufacture.
                ULTRASOUND ???



These are waves of frequency greater than
20KHz.
They travel with velocity of sound.
Because of shorter wave length they travel as
sharp beam.
They undergo reflection.
              BLOCK DIAGRAM


                   ULTRASONIC       ULTRASONIC
 LED SCREEN        TRANSMITTER
                                    RECEIVER




    PIC 16F873      TRANSDUCER
MICROCONTROLLER    DRIVER CIRCUIT   AMPLIFIER




     SIGNAL                         ENVELOPE
                   COMPARATOR       DETECTOR
    HOLDING
    CIRCUIT


                    THRESHOLD
                   VOLTAGE = 0.4V
INTERNAL STRUCTURE OF
ULTRASONIC TRANSDUCER
TRANSMITTER
TRANSMITTER
RECEIVER
OPERATIONAL AMPLIFIERS




                 Rf            100k
          A2                       10
                      Ri        10k
       A  A1  A2  10 100  1000
     AdB  20 log A  20 log 1000  60dB
ENVELOPE DETECTOR
COMPARATOR




          Rb  Vcc
Vref                 = 0.4V
         Ra  Rb 
Ra  1M
Rb  46.51k  47k
SIGNAL HOLD CIRCUIT


             CCP




     S   R   QQ              Remark
                      `
     0   0   1    1            Illegal
     0   1   1    0             Set
     1   0   0    1            Reset
     1   1   QQ           Previous Q state
                      `
1.5ms

        RA5 enable output pin
        goes high
PIC & LED INTERFACE
PROCESS EXPLANATION
FLOW CHART
CAPTURE PROCESS
THE LED DISPLAY




              7 SEGMENT
             COMMON ANODE
LED INTERFACE
           APPLICATIONS
   Robotics & Automation
   Car backing System
   Exploration
    FURTHER DEVELOPMENT
   Assistance for the blind
   Velocity meter
   Long range and short range mode
    selection.
   PC interface.
   Periphery mapper.

								
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