Rbelknap: I fail at copy and paste

2011-02-25T22:24:29Z

I fail at copy and paste

← Older revision		Revision as of 15:24, 25 February 2011
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	[[Category:Sensebridge]		[[Category:Sensebridge]]

Rbelknap: adding category tag

2011-02-25T22:23:25Z

adding category tag

← Older revision		Revision as of 15:23, 25 February 2011
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			[[Category:Sensebridge]

Rachel: New page: Rachel & Mike, March 29(?) Some functional if rough arduino code for a Parallax Ping))) module has been produced. It blinks an LED once per half second, with a larger duty cycle the clos...

2009-04-06T14:32:05Z

New page: Rachel & Mike, March 29(?) Some functional if rough arduino code for a Parallax Ping))) module has been produced. It blinks an LED once per half second, with a larger duty cycle the clos...

New page

Rachel & Mike, March 29(?)

Some functional if rough arduino code for a Parallax Ping))) module has been produced. It blinks an LED once per half second, with a larger duty cycle the closer an object is to the sensor. The Ping))) module is large and somewhat cumbersome, and appears to be quite inaccurate at distances greater than about 2-3 feet. There is a pair of MaxSonar-EZ1 modules in the Cyborg parts bin which look interesting to try as well.

Code:
<pre>
/*
* Based on code found at http://arduino.cc/en/Tutorial/Ping
*/

int pin = 13;
int pingPin = 12;
int ledPin = 11;
double periodFactor = .5; // percent of one second

void setup() // run once, when the sketch starts
{
// pinMode(pin, OUTPUT); // sets the digital pin as output
Serial.begin(9600);
pinMode(ledPin, OUTPUT);
}

void loop() // run over and over again
{
long duration, inches, cm;

// The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
// We give a short LOW pulse beforehand to ensure a clean HIGH pulse.
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);

// The same pin is used to read the signal from the PING))): a HIGH
// pulse whose duration is the time (in microseconds) from the sending
// of the ping to the reception of its echo off of an object.
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH);

// convert the time into a distance
inches = microsecondsToInches(duration);
cm = microsecondsToCentimeters(duration);

Serial.print(inches);
Serial.print("in, ");
Serial.print(cm);
Serial.print("cm");
Serial.println();

pwm(duration);
}

void pwm(long microseconds)
{
Serial.print(microseconds);
Serial.println("ms");

long offCycle = microseconds / 18;
long onCycle = 1000 - offCycle;
digitalWrite(ledPin, HIGH);
delay(onCycle * periodFactor);
digitalWrite(ledPin, LOW);
delay(offCycle * periodFactor);
}

long microsecondsToInches(long microseconds)
{
// According to Parallax's datasheet for the PING))), there are
// 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
// second). This gives the distance travelled by the ping, outbound
// and return, so we divide by 2 to get the distance of the obstacle.
// See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{
// The speed of sound is 340 m/s or 29 microseconds per centimeter.
// The ping travels out and back, so to find the distance of the
// object we take half of the distance travelled.
return microseconds / 29 / 2;
}
</pre>

EBB Notes 1 - Revision history

Rbelknap: I fail at copy and paste

Rbelknap: adding category tag

Rachel: New page: Rachel & Mike, March 29(?) Some functional if rough arduino code for a Parallax Ping))) module has been produced. It blinks an LED once per half second, with a larger duty cycle the clos...