Firebeetle ESP32 vs Arduino Nano IoT 33 coding difference

Projects Programming
1

Hi
I'm trying to use the code that worked with my Nano IoT 33 (Arduino Nano 33 IoT — Arduino Official Store) on the FireBeetle ESP32 (FireBeetle 2 ESP32-E IoT Microcontroller with Header - DFR0654-F | DFRobot Electronics). I'm using a 3,3V HC-SR04 sensor to measure distance, it works on the Nano, but not on the FireBeetle.

// Variables used for Distance monitoring
#define ULTRASONIC_TRIG_PIN D13 // pin TRIG is D11
#define ULTRASONIC_ECHO_PIN D11 // pin ECHO is D12
int trigPin = 13;    // Trigger
int echoPin = 11;    // Echo

// MAIN SETUP
void setup() {
  // set pin modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

// MAIN LOOP
void loop() {
  long duration, firebeetle_distance;
  // 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:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  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);
  Serial.println("Duration is");
  Serial.println(duration);
  Serial.println("");

  // Convert the time into a distance
  firebeetle_distance = (duration / 2) / 29.1;   // Divide by 29.1 or multiply by 0.0343
  Serial.println("Distance is");
  Serial.print(firebeetle_distance);
  Serial.println("");

On the Nano I get correct results, but on the FireBeetle I get:
13:45:18.503 -> Duration is
13:45:18.503 -> 2
13:45:18.503 ->
13:45:18.503 -> Distance is
13:45:18.503 -> 0

or
13:32:46.965 -> Duration is
13:32:46.965 -> 1
13:32:46.965 ->
13:32:46.965 -> Distance is
13:32:46.965 -> 0

What am I doing wrong?

2

what is the result of (2/2)/29.1? 0.something right? and what happens if you assign this to long int? you lose the fraction part so the result is 0. What is not working?

3

no, it should actually be a full number, rounded up. so from the Nano I get 2, 10, whatever number of cm the distance is from the obstruction the sensor detects.
as to the long int, I thought this would be done above, check this line in the original code block:
long duration, firebeetle_distance;

4

Wait what? Never mind, I dont have patience, let someone else explain this to you.

5

Found this, ESP32 with HC-SR04 Ultrasonic Sensor with Arduino IDE | Random Nerd Tutorials. Here it has the distance variable set as float, otherwise everything should be fine.

6

Same exact code on the Nano produced this:
image

7

@killzone_kid I just realized I read over your (2/2)/29.1 <- I missed the first 2. The problem is that the distance is not 2 :slight_smile:
From the code point of view yes, it works. I was thinking maybe I'm making some other mistake, like defining variables on the Firebeetle or something similar.

8

You are printing distance, and it is what it is, in you case it is 2 and 1. pulsIn returns microseconds, right? So maybe you are reading the wrong pin

9

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