Tuesday, June 12, 2018

Arduino Capacitor tester with LCD

By this arduino project you can measure the capacity of capacitors with value between 0.1uF to 3500uF.


Here arduino calculate the capacity value by measuring the time required to charge the capacity to reach 63.2% of source voltage(According to Capacitor time constant formula), then divided this time by resistor value which is 10K to find out the capacitor value.

Arduino Capacitor tester with LCD
Parts list:
Arduino Board
LCD 16x2
Breadboard 
Connecting wire
Potentiometer 10K
Resistor 10K
Resistor 220 ohm(2pcs)

Wiring:
10K resistor used for charging the capacitor and 220 ohm used for discharging.

Capacitor under test with 47uF nominal value

Arduino Capacitor tester with LCD



Capacitor Charge and discharge curve on oscilloscope:


Arduino Capacitor tester with LCD


Code: 

#include <Wire.h>
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
#define analogPin      0         
#define chargePin      13        
#define dischargePin   3       
#define resistorValue  10000.0F  //Remember, we've used a 10K resistor to charge the capacitor

unsigned long startTime;
unsigned long elapsedTime;
float microFarads;               
float nanoFarads;

void setup(){
  pinMode(chargePin, OUTPUT);    
  digitalWrite(chargePin, LOW);
  lcd.begin(16, 2);  //LCD order

}

void loop(){
  digitalWrite(chargePin, HIGH); 
  startTime = micros();
  while(analogRead(analogPin) < 648){      
  }

  elapsedTime= micros() - startTime;
  microFarads = ((float)elapsedTime / resistorValue) ;

    
 
  if (microFarads > 1){

    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Capacitor = ");
    lcd.setCursor(0,1); 
    lcd.print(microFarads);
    lcd.setCursor(9,1);       
    lcd.print("uF");  
    delay(500);   
  }

  else{
    nanoFarads = microFarads * 1000.0;
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Capacitor = ");
    lcd.setCursor(0,1);      
    lcd.print(nanoFarads-11.2); 
    lcd.setCursor(9,1);      
    lcd.print("nF");         
    delay(500);
  }

 
 
  digitalWrite(chargePin, LOW);           
  pinMode(dischargePin, OUTPUT);           
  digitalWrite(dischargePin, LOW);     //discharging the capacitor    
  while(analogRead(analogPin) > 0){        
  }//This while waits till the capaccitor is discharged

  pinMode(dischargePin, INPUT);      //this sets the pin to high impedance


}