Stopping turning servo motor after an obstacle is detected by ultrasonic sensor with Arduino

Question

I want to stop a servo motor which turns continuously until an obstacle is detected by ultrasonic sensor. For instance, I want the servo motor to stop when the obstacle is within 5 cm of the ultrasonic sensor. If there is no obstacle, servo motor should turn without stopping.

However, after the obstacle is removed, my servo motor starts rotating from a different angle, not where it stops. I added servo motor rotation part of Arduino code.`

  void loop() {

    for (int i=0; i<=180; i++) {  
      distance = calculateDistance();
      if (distance <= 10){
        moveStop();
      } else {  
        moveForward();
        myServo.write(i);
        delay(5);  
      } 
    }

    for (int i=180; i>0; i--) {  
      distance = calculateDistance();
      if (distance <= 10) {
        moveStop();
      } else {  
        moveForward();
        myServo.write(i);
        delay(5);
      }

Answer 1

the problem is that i gets continously counted even when the object is in the way. cant recreate your setup exactly but I hope this helps you out

int y = 0


void loop() {

  for(int i=0;i<=180;i++){  

    distance = calculateDistance();
    if (distance <= 10){
      moveStop();
      y++;                  //"counts the time" the servo is blocked by object
      }
    else{  
      moveForward();
      myServo.write(i-y);   //and subtracts that time from i
      delay(5);  
      } 
    }

  for(int i=180;i>0;i--){  

  distance = calculateDistance();
  if (distance <= 10){
    moveStop();
    y++;
    }
  else{  
    moveForward();
    myServo.write(i+y);              //same but in reverse
    delay(5);
    }

Answer 2

Make some tweaks according to your use.Please refer if there is any problemhttps://forum.arduino.cc/t/making-a-servo-stop-when-an-object-is-detected-using-hc-sr04/587485/8

#include <Servo.h>
const int servoPin = 9; // the pin number for the servo signal
const int trigPin = 11; //ultrasonic
const int echoPin = 12; //ultrasonic


const int servoMinDegrees = 0; // the limits to servo movement
const int servoMaxDegrees = 180;


Servo myservo;  // create servo object to control a servo 

int servoPosition = 0;     // the current angle of the servo - starting at 90.
int servoSlowInterval = 20; // millisecs between servo moves
int servoFastInterval = 20;
int servoInterval = servoSlowInterval; // initial millisecs between servo moves
int servoDegrees = 2;       // amount servo moves at each step 
                           //    will be changed to negative value for movement in the other direction

unsigned long currentMillis = 0;    // stores the value of millis() in each iteration of loop()
unsigned long previousServoMillis = 0; // the time when the servo was last moved



void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  
  myservo.write(servoPosition); // sets the initial position
  myservo.attach(servoPin);
}

void loop() {
 
  // put your main code here, to run repeatedly:

     // Notice that none of the action happens in loop() apart from reading millis()
     //   it just calls the functions that have the action code

 currentMillis = millis();   // capture the latest value of millis()
                             //   this is equivalent to noting the time from a clock
                             //   use the same time for all LED flashes to keep them synchronized

                              // establish variables for duration of the ping, 
  // and the distance result in inches and centimeters:
  long duration, inches, cm;
  
  // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(trigPin, OUTPUT);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Read the signal from the sensor: 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(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
  
  // convert the time into a distance
  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);
  
  //Tell the Arduino to print the measurement in the serial console
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();

   if (cm > 50)  {servoSweep();
    
   
   }
   else if (cm &lt;= 50) {myservo.write(servoPosition);
    
   }
  
}
// Converts the microseconds reading to Inches
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;
}
//Converts the Microseconds Reading to Centimeters
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;

  
}


//========

void servoSweep() {

     // this is similar to the servo sweep example except that it uses millis() rather than delay()

     // nothing happens unless the interval has expired
     // the value of currentMillis was set in loop()
 
 if (currentMillis - previousServoMillis >= servoInterval) {
       // its time for another move
   previousServoMillis += servoInterval;
   
   servoPosition = servoPosition + servoDegrees; // servoDegrees might be negative

   if (servoPosition &lt;= servoMinDegrees) {
         // when the servo gets to its minimum position change the interval to change the speed
      if (servoInterval == servoSlowInterval) {
        servoInterval = servoFastInterval;
      }
      else {
       servoInterval = servoSlowInterval;
      }
   }
   if ((servoPosition >= servoMaxDegrees) || (servoPosition &lt;= servoMinDegrees))  {
         // if the servo is at either extreme change the sign of the degrees to make it move the other way
     servoDegrees = - servoDegrees; // reverse direction
         // and update the position to ensure it is within range
     servoPosition = servoPosition + servoDegrees; 
   }
       // make the servo move to the next position
   myservo.write(servoPosition);
       // and record the time when the move happened
 }
}