I need your suggestions and help with my Ping Sensor. I have an Arduino Uno with a Parallax Ping sensor and a motor attatched to the motor.
My ping sensor is set to to start the motor when the nearest object is <= 10cm. That works fine. Now, I'd like the motor to start only if the values of the sensor are progressing in a decreasing manner i.e 15, 14, 13, 12, 11, 10 but do nothing if the values of distance are progressing in a increasing manner.
I was thinking if I stored the last 3 pings as variables and using an if/else statement but I don't know how to implement it.
How can I implement this, or if you have any other suggestion, please help me. Thank you
Here is what i have so far:
/* Ping))) Sensor
This sketch reads a PING))) ultrasonic rangefinder and returns the
distance to the closest object in range. To do this, it sends a pulse
to the sensor to initiate a reading, then listens for a pulse
to return. The length of the returning pulse is proportional to
the distance of the object from the sensor.
The circuit:
* +V connection of the PING))) attached to +5V
* GND connection of the PING))) attached to ground
* SIG connection of the PING))) attached to digital pin 7
http://www.arduino.cc/en/Tutorial/Ping
created 3 Nov 2008
by David A. Mellis
modified 30 Aug 2011
by Tom Igoe
This example code is in the public domain.
*/
// this constant won't change. It's the pin number
// of the sensor's output:
const int pingPin = 7;
const int motorPin = 9;
//Yomis code
//int pings[3] = {-1,-1,-1};
//int i;
//bool Increasing(int p1, int p2, int p3)
//{
// if(p1 < p2 && p2 < p3){
// return true;
// }
//}
//
//bool Decreasing(int p1, int p2, int p3)
//{
// if(p1 > p2 && p2 > p3){
// return true;
// }
//}
//
//end of yomis code
void setup() {
// Set up the motor pin to be an output:
pinMode(motorPin, OUTPUT);
// initialize serial communication:
Serial.begin(9600);
}
void loop()
{
// establish variables for duration of the ping,
// and the distance result in inches and centimeters:
long duration, inches, cm;
// The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(1000);
digitalWrite(pingPin, HIGH);
delayMicroseconds(2000);
digitalWrite(pingPin, LOW);
// 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();
delay(1000);
// //Yomis code
// if (cm <= 10)
// {
// Serial.println();
// Serial.println(pings[0]);
// Serial.println(pings[1]);
// Serial.println(pings[2]);
// Serial.println();
// if(Increasing(pings[0],pings[1],pings[2]))
// {
// int Speed1 = 100; // between 0 (stopped) and 255 (full speed)
// int Time1 = 3000; // milliseconds for speed 1
// analogWrite(motorPin, Speed1); // turns the motor On
// }
// }
// else
// {
// analogWrite(motorPin, LOW);
// }
//
// //End of yomis code
if (cm <= 10) {
int Speed1 = 150; // between 0 (stopped) and 255 (full speed)
int Time1 = 2000; // milliseconds for speed 1
int Speed2 = 250; // between 0 (stopped) and 255 (full speed)
int Time2 = 3000; // milliseconds to turn the motor off
analogWrite(motorPin, Speed1); // turns the motor On
delay(Time1); // delay for onTime milliseconds
// analogWrite(motorPin, Speed2); // turns the motor Off
// delay(Time2); // delay for offTime milliseconds
}
else if (cm > 10) {
analogWrite(motorPin, LOW); // turn the motor off
}
else {
Serial.print(inches);
Serial.print("in, ");
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(100);
}
}
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.m
// 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;
}
