Ultrasonic distance sensor to activate 2 servo motors

Projects Programming
1

Hey,

I'm trying to code an ultrasonic distance sensor to activate 2 servo motors when the distance measured is less than 50 cm. So far I can get the readings right but the motors don't move. Does this code look ok to you? Is something wrong with it?

I can make everything work separately... Make the motors move without the sensor... The problem is that once I try to put everything together, they stop moving :confused:

This is my first time trying to do something with Arduino on my own, so I apologize in advance if the problem is super easy to solve and I just couldn't figure it out x)

#include <Servo.h>
#define pingPin 7
int oldCm = 0;
int threshold = 50;
int pos = 0;
Servo servoBottom;
Servo servoTop;


void setup() {
  Serial.begin(9600);
}

void loop() {

  long duration, cm;

  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);

  pinMode(pingPin, INPUT);
  duration = pulseIn(pingPin, HIGH);
  cm = microsecondsToCentimeters(duration);

  if (cm  != oldCm){
  Serial.println(cm);
  oldCm = cm;
  }

  delay(100);
  
  if(cm < threshold){
    for (pos = 0; pos <= 100; pos += 1) {
      servoBottom.write(pos);
      delay(7);
      servoTop.write(pos);
      delay(7);}
  }
}

long microsecondsToCentimeters(long microseconds) {
  return microseconds / 29 / 2;
}

Cheers!

2

You don't appear to be doing anything (useful) with oldCm. So, why does it even exist?

Do you get a value in cm that is less than 50?

How are the servos powered?

3

I'm trying to code an ultrasonic distance sensor to activate 2 servo motors when the distance measured is less than 50 cm. So far I can get the readings right but the motors don't move. Does this code look ok to you? Is something wrong with it?

Sorry, but I don't watch your code.

You must check this:

  1. Arduino Playground - HomePage
    2.Servo - Arduino Reference

And then try it make together.

#include <NewPing.h>
#include <Servo.h>

#define TRIGGER_PIN  11  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     12  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards
Servo myservo2; // create servo2 object to control a servo

int pos = 0;    // variable to store the servo position

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.

void setup() {

  Serial.begin(115200);

  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  myservo2.attach(10); // attaches the servo2 on pin 10 to the servo object
}

void loop() {

  delay(1000);
  Serial.print("Ping: ");
  Serial.print(sonar.ping_cm()); // Send ping, get distance in cm and print result (0 = outside setdistance range)
  Serial.println("cm");


  if (sonar.ping_cm() < 50 && sonar.ping_cm() > 1) { // if distance is less then 50 cm and greater 1 cm
    for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
      // in steps of 1 degree
      myservo.write(pos);      // tell servo to go to position in variable 'pos'
      myservo2.write(pos);    // tell servo2 to go to position in variable 'pos'
      delay(15);                       // waits 15ms for the servo to reach the position
    }
    for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
      myservo.write(pos);              // tell servo to go to position in variable 'pos'
      myservo2.write(pos);             // tell servo2 to go to position in variable 'pos'
      delay(15);                       // waits 15ms for the servo to reach the position
    }
  } else {                                      //do nothing
    pos = 0; {
      myservo.write(pos);
      myservo2.write(pos);
      delay(15);                   // waits 15ms for the servo to reach the position
    }
  }
}