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This sketch reads a PING))) ultrasonic rangefinder and returns the
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distance to the closest object in range. To do this, it sends a pulse
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to the sensor to initiate a reading, then listens for a pulse
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to return. The length of the returning pulse is proportional to
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the distance of the object from the sensor.
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based on the original code from the tutorial at:
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http://www.arduino.cc/en/Tutorial/Ping
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This example code is in the public domain.
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long duration, inches, cm;
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//pinMode(13, OUTPUT);
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pinMode(pingPin, OUTPUT);
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pinMode(inPin, INPUT);
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long microsecondsToInches(long microseconds)
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// According to Parallax's datasheet for the PING))), there are
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// 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
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// second). This gives the distance travelled by the ping, outbound
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// and return, so we divide by 2 to get the distance of the obstacle.
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return microseconds / 74 / 2;
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long microsecondsToCentimeters(long microseconds)
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// The speed of sound is 340 m/s or 29 microseconds per centimeter.
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// The ping travels out and back, so to find the distance of the
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// object we take half of the distance travelled.
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return microseconds / 29 / 2;
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// The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
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// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
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//pinMode(pingPin, OUTPUT);
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digitalWrite(pingPin, LOW);
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digitalWrite(pingPin, HIGH);
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delayMicroseconds(10);
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digitalWrite(pingPin, LOW);
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//delayMicroseconds(2);
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// pulse whose duration is the time (in microseconds) from the sending
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// of the ping to the reception of its echo off of an object.
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duration = pulseIn(inPin, HIGH);
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// convert the time into a distance
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inches = microsecondsToInches(duration);
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cm = microsecondsToCentimeters(duration);
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Serial.print("Distance: [");
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Serial.print("]inches. [");
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Serial.print("]cm\r\n");
added
removed
test/ultrasonic-prox/main.ino
