Digital Scale

In this workhop we will learn how to how to make a digital scale to measure distance.

Problem Statement

In order to measure distance from some physical thing we can use scale or measuing tap, but what if we need to need to take continous measurement and analyize the differnce, or we need to make an action depends on the distance like water level, waste level, oil level etc. repetitive continous measurement cost too much human resource.

Idea

What if, we have a system that can be continually monitor the level and make actions.

Solution

Build a device that can be controled wcontinually monitor the level and make actions like getting notification when a waste bin is full or getting a notification that can be help to prevent flood by monitoring water level..etc

Prototype Building

Build a device that Measure distace and displayed on LCD Screen

Here we are using an Arduino as controller and HCSR04 Ultrasonic Module to measure the distance and 16x2 LCD Display to Display the Distance.

digram

Things we need

Arduino Uno
HCSR04 Ultrasonic sensor
16x2 LCD Module
10k ohm potentiometer
220 ohm resistor
Jumper Wires
Breadboard

Ultrasonic Sensor

Ultrasonic sensors work by sending out a sound wave at a frequency above the range of human hearing. The transducer of the sensor acts as a microphone to receive and send the ultrasonic sound.

It emits an ultrasound at 40 000 Hz which travels through the air and if there is an object or obstacle on its path It will bounce back to the module. Considering the travel time and the speed of the sound you can calculate the distance.

HCSR04

The HC-SR04 Ultrasonic Module has 4 pins, Ground, VCC, Trig and Echo. The Ground and the VCC pins of the module needs to be connected to the Ground and the 5 volts pins on the Arduino Board respectively and the trig and echo pins to any Digital I/O pin on the Arduino Board.

HCSR04

LCD Module

An LCD is an electronic display module which uses liquid crystal to produce a visible image. The 16×2 LCD display is a very basic module commonly used in DIYs and circuits. The 16×2 translates o a display 16 characters per line in 2 such lines. In this LCD each character is displayed in a 5×7 pixel matrix.

LCD Pinout

Pin Description

LCD Pin Description

Step 1: Arduino Setup

1.1: Install Arduino IDE

Download the Arduino IDE and install it on your computer.

Arduino IDE Download

1.2 walk-through the Arduino Introduction page to learn basics

If you are new to the arduino system, you can learn the Arduino basics from here , after reading then go to the next step.

Step 2: Programming

2.1 Algorithm

algorithm

2.2 Open Arduino IDE and Start a new Sketch

Arduino IDE Sketch

2.3 Read then Copy and Paste the Code

Tesing HCSR04 UltraSonic Module


const int trigPin = 9;   // defines Pin 9 as Trigger Pin
const int echoPin = 10; // define Pin 10 as Echo Pin

//define Variables
long duration;
int distance;


void setup() {

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  Serial.begin(9600);     // Starts the serial communication

}
void loop() {

  digitalWrite(trigPin, LOW);     // Clears the trigPin
  delayMicroseconds(2);          // wait for 2 micro second
  digitalWrite(trigPin, HIGH);  // Sets the trigPin on HIGH state
  delayMicroseconds(10);       // wait 10 micro second
  digitalWrite(trigPin, LOW); // Sets the trigPin on LOW state

  duration = pulseIn(echoPin, HIGH); // Reads the echoPin, returns the sound wave travel time in microseconds

  distance = duration * 0.034 / 2;  // Calculating the distance

  Serial.print("Distance: ");
  Serial.println(distance);     // Prints the distance on the Serial Monitor

  delay(500);                  // wait 500 milli second
}

2.4 Compile the code

You can Compile and verify your code by clicking the Verify button on Arduino IDE, this process will check syntax errors.

verify code

after successful compilation you can see Done Compiling

done verify

2.5 Upload the code into Arduino uno

After successful compilation we can upload the code into Arduino Uno Devlopment board. for that we need click **Upload button.

uploadcode

before upaloading we need to select the devlopment board from the from Arduino IDE Tools -> Board and Port from Arduino IDE Tools -> Port.

selectport

selectboard

here I selected Arduino Uno as board and COM26 as Port.

Then click Upload

doneupload

2.5 Connect the HCSR04 Module to Arduino

HCSR04 Connection

We can test the project from halfway without LCD module by using Serial Monitor .

After connecting the HCSR04 on arduino connect the USB cable and Open Serial Monitor .

serial monitor

Distance Test

We can see the distance measured from the Ultrasonic sensor from the Serial Monitor Window

Serial Distance

Tesing LCD Module

Here we are using LCD Module with 12C addons for I2C Communication , which will only need two wires for communication, in other way we need to use 14 pins.

Since the I2C is a addon we need to insert the library on Arduino IDE first. For that first downlaod the Arduino-LiquidCrystal-I2C-library.zip, Then click Sketch -> Include Library -> Add .ZIP Library

inlcude lib

then select the .Zip file and click open. add zip file

now we successfully added the I2C library.

Uplaod and Compaile Code

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup()
{
	// initialize the LCD
	lcd.begin();

	// Turn on the blacklight and print a message.
	lcd.backlight();
	lcd.print("Hello, world!");
}

void loop()
{
	lcd.setCursor(0, 1);
  lcd.print(millis() / 1000);
  
}

Connect LCD Module with Arduino

Demonstrates the use a 16x2 LCD display. The I2C LiquidCrystal Module comes with 4-pins and connect them with follwing model.

LCD SCL - Arduino SCL
LCD SDA - Arduino SDA
LCD GND - Arduino GND
LCD VCC - Arduino VCC

This sketch prints “Hello World!” to the LCD and shows the time.

lcd connection

lcd demo

Step 3: Combine both HCSR04 and LCD Module

We tested both and now we need to combine the both hardware and progrmmes into one.

3.1: Upload code.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);

const int trigPin = 9;   // defines Pin 9 as Trigger Pin
const int echoPin = 10; // define Pin 10 as Echo Pin

//define Variables
long duration;
int distance;


void setup() {

  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  Serial.begin(9600);     // Starts the serial communication

  // initialize the LCD
  lcd.begin();

  // Turn on the blacklight and print a message.
  lcd.backlight();
  lcd.print("Digital Scale-cm");

}
void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Digital Scale-cm");

  digitalWrite(trigPin, LOW);     // Clears the trigPin
  delayMicroseconds(2);          // wait for 2 micro second
  digitalWrite(trigPin, HIGH);  // Sets the trigPin on HIGH state
  delayMicroseconds(10);       // wait 10 micro second
  digitalWrite(trigPin, LOW); // Sets the trigPin on LOW state

  duration = pulseIn(echoPin, HIGH); // Reads the echoPin, returns the sound wave travel time in microseconds

  distance = duration * 0.034 / 2;  // Calculating the distance
  //String dist = distance + "cm" ;
  Serial.print("Distance: ");
  Serial.println(distance);     // Prints the distance on the Serial Monitor

  lcd.setCursor(0, 1);          //Set cursor to second line
  lcd.print(distance);          // Print distnace on LCD

  delay(500);                  // wait 500 milli second

  lcd.clear();                //Clear the LCD.
}

Wiring

Final Demo

Demo

ToDO

Add button and measure only when the button pressed.
Add buzzer and trigger when a speacial requirment.
Designa and 3D Print Enclosure.

Thank You, Hope you enjoyed!

Please share your feedback.

Prototyping

Learn Rapid prototyping by Doing.