SetNFix
Published © GPL3+

Arduino Voltmeter

Voltmeter using arduino amd LCD display.

IntermediateFull instructions provided10,731
Arduino Voltmeter

Things used in this project

Hardware components

Solderless Breadboard Half Size
Solderless Breadboard Half Size
×1
Jumper wires (generic)
Jumper wires (generic)
×1
Resistor 10k ohm
Resistor 10k ohm
×1
Through Hole Resistor, 120 ohm
Through Hole Resistor, 120 ohm
×1
Resistor 100k ohm
Resistor 100k ohm
×1
Rotary potentiometer (generic)
Rotary potentiometer (generic)
×1
Arduino UNO
Arduino UNO
×1

Hand tools and fabrication machines

Mastech MS8217 Autorange Digital Multimeter
Digilent Mastech MS8217 Autorange Digital Multimeter
Soldering iron (generic)
Soldering iron (generic)
Solder Wire, Lead Free
Solder Wire, Lead Free

Story

Read more

Schematics

Circuit

There are two diagrams

Code

Arduino Voltmeter

Arduino
Arduino code for voltmeter
#include <LiquidCrystal.h>

/*
  LiquidCrystal Library - Hello World

 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.

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

  The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * LCD VSS pin to ground
 * LCD VCC pin to 5V
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 22 Nov 2010
 by Tom Igoe
 modified 7 Nov 2016
 by Arturo Guadalupi

 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/LiquidCrystalHelloWorld
 
 Modified by : BMIAK Basnayaka for SETNFIX
 Date : 22/04/2021
 http://setnfix.com

*/

// include the library code:
#include <LiquidCrystal.h>

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
int analogInput = 0;
float vout = 0.0;
float vin = 0.0;
float R1 = 100000.0; // resistance of R1 (100K) -see text!
float R2 = 10000.0; // resistance of R2 (10K) - see text!
int value = 0;

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  
  lcd.print("SetNFix");
     pinMode(analogInput, INPUT);
Serial.begin(9600);
  delay(5000);
}

void loop() {
  
     // read the value at analog input
   value = analogRead(analogInput);
   vout = (value * 5.0) / 1024.0; // see text
   vin = vout / (R2/(R1+R2)); 
   if (vin<0.09) {
   vin=0.0;//statement to quash undesired reading !
} 
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 0);
  lcd.print("Volt Meter");
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  unsigned int len = sizeof(vin);
  len = len +2;
  
  lcd.print(vin);
  lcd.print(" ");
  //lcd.setCursor(len, 1);
   lcd.print("Volts");
  lcd.print(" ");
}

Credits

SetNFix

SetNFix

16 projects • 34 followers
I am an accountant in profession but, I would more prefer to work with electronics based innovations.

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