Ultrasonic Distance sensor HC-04 with Arduino – DIY Distance Meter project

DIY  distance meter with an Arduino and ultrasonic distance sensor

Hi Folks, Ones again I am going to write an Arduino Tutorial to explain you how you can use ultrasonic distance sensor with an Arduino and print the output value on OLED display. If you don’t no how to connect and use OLED display then please watch my previous Arduino with OLED Display tutorial.

Video tutorial of Ultrasonic distance meter with Arduino

Connect distance sensor and OLE display to Arduino – Circuit diagram

For this project I am using Arduino pro mini, Please refre the below circuit diagram to connect OLED display and distance sensor to the arduino.

Scanner Code to find the I2C device address

/*
CircuitMagic.com
*/
/*
CircuitMagic.com
*/
#include 
void setup()
{
  Wire.begin();
 
  Serial.begin(9600);
  Serial.println("\nI2C Scanner");
}
void loop()
{
  byte error, address;
  int nDevices;
 
  Serial.println("Scanning...");
 
  nDevices = 0;
  for(address = 1; address < 127; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
 
    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");
 
      nDevices++;
    }
    else if (error==4)
    {
      Serial.print("Unknow error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }   
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");
 
  delay(5000); // wait 5 seconds for next scan
}

Arduino Code to run the distance meter prototype

/*
CircuitMagic.com
*/

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);
#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2
#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH  16
static const unsigned char PROGMEM logo16_glcd_bmp[] =
{
    B00000000, B11000000,
    B00000001, B11000000,
    B00000001, B11000000,
    B00000011, B11100000,
    B11110011, B11100000,
    B11111110, B11111000,
    B01111110, B11111111,
    B00110011, B10011111,
    B00011111, B11111100,
    B00001101, B01110000,
    B00011011, B10100000,
    B00111111, B11100000,
    B00111111, B11110000,
    B01111100, B11110000,
    B01110000, B01110000,
    B00000000, B00110000
}
;
#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif



// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;

// defines variables
long duration;
int distance;

//------code for RPM----------------
int encoder_pin = 2;
// The pin the encoder is connected
unsigned int rpm;
// rpm reading
volatile byte pulses;
// number of pulses
unsigned long timeold;
// The number of pulses per revolution
// depends on your index disc!!
unsigned int pulsesperturn = 1;
void counter()
{
    //Update count
    pulses++;
}
//-----------------------------------
void setup()   {
    Serial.begin(9600);
    // by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
    // initialize with the I2C addr 0x3D (for the 128x64)
    // init done
    // Show image buffer on the display hardware.
    // Since the buffer is intialized with an Adafruit splashscreen
    // internally, this will display the splashscreen.
    //display.display();
    //delay(2000);
    // Clear the buffer.
    //display.clearDisplay();
    // draw a single pixel
    //display.drawPixel(10, 10, WHITE);
    // Show the display buffer on the hardware.
    // NOTE: You _must_ call display after making any drawing commands
    // to make them visible on the display hardware!
    //display.display();
    //delay(2000);
    

    pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
    pinMode(echoPin, INPUT); // Sets the echoPin as an Input
}
void loop()
{
      // Clears the trigPin
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    
    // Sets the trigPin on HIGH state for 10 micro seconds
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    
    // Reads the echoPin, returns the sound wave travel time in microseconds
    duration = pulseIn(echoPin, HIGH);
    
    // Calculating the distance
    distance= duration*0.034/2;

    
   if (millis() - timeold >= 500){
        /*Uptade every one second, this will be equal to reading frecuency (Hz).*/
        //Don't process interrupts during calculations
        detachInterrupt(0);
        //Note that this would be 60*1000/(millis() - timeold)*pulses if the interrupt
        //happened once per revolution
        //rpm = (60 * 1000 / pulsesperturn )/ (millis() - timeold)* pulses;
        timeold = millis();
        pulses = 0;
        //Write it out to serial port
        //Serial.print("Distance = ");
       // Serial.println(rpm,DEC);
        updateDisplay(distance);
        //Restart the interrupt processing
        attachInterrupt(0, counter, FALLING);
    }

    
    
    // Prints the distance on the Serial Monitor
    Serial.print("Distance: ");
    Serial.println(distance);
}
int valLen;
int displayWidth = 128;
int letterWidth = 19;
void updateDisplay(int distance){
  if(distance > 9999)
    valLen = 5;
  else if(distance > 999)
    valLen = 4;
  else if(distance > 99)
    valLen = 3;
  else if(distance > 9)
    valLen = 2;
  else
    valLen = 1;
  
  //-------------update display------------

        display.clearDisplay();
        // text display tests
        display.setTextSize(1);
        display.setTextColor(WHITE);
        display.setCursor(30,0);
        display.println("CircuitMagic");
        display.setTextColor(BLACK, WHITE);
        // 'inverted' text
        //display.println(3.141592);
        display.setTextSize(2);
        display.setTextColor(WHITE);
        display.setCursor(20,20);
        display.println("Distance");
        display.setCursor((displayWidth/2)-(letterWidth/2*valLen),42);
        display.setTextSize(2);
        String distanceS = String(distance) + "cm";
        display.println(distanceS);
        // display.println(0xDEADBEEF, HEX);
        display.display();
        //----------------------
}