#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);
#include "HX711.h"
#define DOUT  23
#define CLK  19
#define BUZZER 25
HX711 scale(DOUT, CLK);
#define BLYNK_PRINT Serial

char auth[] = "*******";
char ssid[] = "*******";
char pass[] = "********";

int liter;
int val;
float weight; 
float calibration_factor = 102500; // change this value for your Load cell sensor 
 
void setup() {
  // Set up serial monitor
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  pinMode(BUZZER ,OUTPUT);
  Serial.println("Remove all weight from scale");
  scale.set_scale();
  scale.tare(); //Reset the scale to 0
  long zero_factor = scale.read_average(); //Get a baseline reading
  Serial.print("Zero factor: "); //This can be used to remove the need to tare the scale. Useful in permanent scale projects.
  Serial.println(zero_factor);
  Blynk.begin(auth, ssid, pass); 
}
 void loop() {
 Blynk.run();
 measureweight();
}
 
void measureweight(){
 scale.set_scale(calibration_factor); //Adjust to this calibration factor
  weight = scale.get_units(5); 
    if(weight<0)
  {
    weight=0.00;
    }
  liter = weight*1000;
  val = liter;
  val = map(val, 0, 505, 0, 100);
  lcd.clear();
  lcd.setCursor(1, 0);
  lcd.print("IOT Based IV Bag");
  lcd.setCursor(2, 1);
  lcd.print("Monitering System");
  Serial.print("Kilogram: ");
  Serial.print(weight); 
  Serial.println(" Kg");
  lcd.setCursor(1, 2);
  lcd.print("IV Bottle = ");
  lcd.print(liter);
  lcd.print(" mL");
  Serial.print("IV BOTTLE: ");
  Serial.print(liter);
  Serial.println("mL");
  lcd.setCursor(1, 3);
  lcd.print("IV Bag Percent=");
  lcd.print(val);
  lcd.print("%");
  Serial.print("IV Bag Percent: ");
  Serial.print(val);
  Serial.println("%");
  Serial.println();
  delay(500);
  if (val <= 50 && val >= 40){
    Blynk.logEvent("iv_alert","IV Bottle is 50%");
    digitalWrite(BUZZER, HIGH);
    delay(50);
    digitalWrite(BUZZER, LOW);
    delay(50);
  }
  else if (val <= 20){
    Blynk.logEvent("iv_alert","IV Bottle is too LOW");
    digitalWrite(BUZZER, HIGH);
  }
  else{
    digitalWrite(BUZZER, LOW);
  }
  Blynk.virtualWrite(V0,liter);
  Blynk.virtualWrite(V1,val);
} 

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Read inputs from stdin

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#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
} 

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
} 

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}  

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition); 

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}