Why Duration is 0?

[inotplayingrn]

I want it to measure distance but i can't because duration is 0 Please Help me(Board: Arduino MKR 1010 Wifi with MKR Carrier Explore IOT Kit)(Use on IOT Cloud)

const int trigPin = 2;
const int echoPin = 3;

long duration;
int distance;
void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
}
void loop() {
 
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
 
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  Serial.print("Duration: ");
  Serial.println(duration);
  Serial.print("Distance: ");
  Serial.println(distance);
  delay(100);
}

[kolaha]

it is 5V device on 3.3V MCU;
maybe wrong connection;
maybe try this

const int trigPin = 2;
const int echoPin = 3;

long duration;
int distance;
void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
}
void loop() {
 
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(trigPin, LOW);
 
  duration = pulseIn(echoPin, HIGH);
  distance = (duration * 17)/1000;
  Serial.print("Duration: ");
  Serial.println(duration);
  Serial.print("Distance: ");
  Serial.println(distance);
  delay(100);
}

[inotplayingrn]

It pin on 5V pin already

[Paul_KD7HB]

@inotplayingrn

duration = pulseIn(echoPin, HIGH);

Please READ the documentation on the pulseLn() function call. It always returns ZERO when the time-out occurs! Since you did not specify a time-out value, one second is used by default.

[kolaha]

@Paul_KD7HB

time-out occurs

if distance larger as 163m

[Paul_KD7HB]

@kolaha

if distance larger as 163m

No, if NO echo return is detected.

[kolaha]

are you mean it was no trigger signal at all? if it was there it should return because it is indoor.

[Paul_KD7HB]

Did you read the pulseLn() documentation to see why zero is returned? It is returned because the pulse has not ended by the time the time-out period has occurred. That is caused by the device not detecting an echo return for ANY reason!

[kolaha]

this is correct, but which reason it might be?
1 distance was too large for this particular setting of timeout, default 1000000µs is travel of 343m;
2 it was no trigger signal at all, for any reason;
3 trigger signal is too weak and/or absorbed on obstacles.
do i forget something?

[inotplayingrn]

i try this code but duration still 0 ;-;

[kolaha]

do you have Uno, Nano, Micro, Leonardo, Mega?

[inotplayingrn]

i have esp8266 and esp32 lol but i can borrow my friend(uno)

[kolaha]

try on yours and on Uno.

[inotplayingrn]

okie thanks

[Paul_KD7HB]

@kolaha

do i forget something?

Yes, you did. The object MUST be able to reflect the sound pulse back to the sensor. Using a pencil or a blanket, or your hand or any other soft material could be the reason. Or the reflection is NOT directly back to the sensor.

[kolaha]

@Paul_KD7HB

reflect the sound pulse back to the sensor

this is normal end of pulseIn(), no timeout occurs

@Paul_KD7HB

the reflection is NOT directly back to the sensor.

variant 3.

well, nothing forgot.

btw it is so simple to check if it timeout issue

duration = pulseIn(echoPin, HIGH, 5000000);

@inotplayingrn would you please test it?

[inotplayingrn]

okie

[J-M-L]

actually you have a wiring problem, your sensor is not powered

you need to add short wires to continue the blue and red rails across