PING Ultrasonic Distance Sensors and Applications

PING ultrasonic distance sensor is a sensor 40 kHz Parallax production is widely used for applications / robot contest. Advantages of this sensor is that only requires 1 signal (SIG), in addition to the 5V and ground lines.

PING sensor detects the distance of objects by emitting ultrasonic waves (40kHz) during tBURST (200us), then detect the reflection. PING sensors emit ultrasonic waves according to the control of the controlling microcontroller (trigger pulse with the tOUT min 2us).
This sensor specification is as follows:

• Measurement range of 3cm - 3m.
• Input trigger-positive TTL pulse, 2 us min., 5 us typical.
• Echo hold off 750 us from fall of trigger pulse.
• Delay before next measurement 200 us.
• Burst indicator LED displays the activity of sensor.

Ultrasonic waves through the air at speeds of 344 m / s, then hit the object and is reflected back to the sensor. PING produces high output pulse on pin SIG after emitting an ultrasonic wave and after wave reflection is detected, PING will make the output  low on the pin SIG. High pulse width (tIN) will be in accordance with the long travel time of ultrasonic waves to  2 times the measure distance to the object. Thus, the measured distance is [(tIN s x 344 m/s) : 2] meters.
To try this sensor is required DT Basic Mini System and Software Basic Stamp Editor to program the microcontroller and try this sensor. The output of the SIG pin is connected to one port on the microcontroller kit. The following examples of sensor applications on the PING Basic Stamp 2 microcontroller, which pin SIG is connected to P9 and provide 5V power supply and ground.  Function of PULSOUT is to trigger PING, while  function of PULSIN is used to measure the pulse corresponding to the distance from the target object.

//Program to test PING distance sensor with DT-Basic Mini System

'{$STAMP BS2p}

'{PBASIC 2.5}

ping PIN 9 //connected to P9

// check type of Basic Stamp

#SELECT $stamp

#CASE BS2,BS2E

trigger CON 13

scale CON $0cd

#ENDSELECT

//constant calculation

rawtoin CON 889

rawtocm CON 2257

isHigh CON 1

isLow CON 0

rawDist VAR Word

inches VAR Word

cm VAR Word

reset:

//displays a message in the window

DEBUG CLS,  "Paralaxx PING Sonar" ,CR,

"=============================",CR,

CR,

"Time  (uS)    . . .  ",CR,

"Inches . . . . .  ",CR,

"Centimeters . . . "

Main:

Do

GOSUB get_sonar //call function get_sonar

inches=rawDist ** RawToIn

cm=rawDist ** RawToCm

//display the calculation results

DEBUG CRSRXY, 15, 3,

     DEC rawDist, CLREOL,

          CRSRXY, 15, 4,

          DEC inches, CLREOL,

          CRSRXY, 15, 5,

          DEC cm, CLREOL

          PAUSE 100

          LOOP

          END

get-sonar :   //main code

          ping =IsLow

          PULSOUT ping, trigger

          PULSIN ping, isHigh, rawDist

          rawDist=rawDist */Scale

          rawDist =rawDist/2

RETURN

Then run the above program, then record the lowest and highest values ​​measured in centimeters and also observe the influence of the emission angle of the measurement results.

There are PING sensor and other Distance sensor Selections :

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