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  2. Arduino USB2serial programming the bare bone
  3. Arduino Projects Videos added
  4. Arduino Xbee projects
  5. Arduino dB Meter 
  6. Trying to get the IOIO going. 
  7. IOIO is going....bluetooth
  8. Attiny 2313 bluetooth bee RC car
  9. Compass and temperature added
  10. AVR programmer
  11. USB2Serial and Ethernet POE
  12. Arduino LPG Sensor
  13. Program the Arduino Mini 05
  14. Lipo Rider Pro in action
  15. EZ Robot Builder kit arrived 10 Nov 2012
  16. Arduino VA Meter!
  17. 05 Nov 2012 Project Sentry Gun.
  18. Attiny85 PIR Sensor 10 Dec 2012 
  19. 0-30VDC3A and 2-28VDC10A bench PSU's
  20. 19 Dec 2012 Arduino Voltmeter LCD
  21. 29 Dec 2012 Arduino Tachometer&Speedometer LCD
  22. 03 Jan 2013 Arduino AC Phase Control. 
  23. 18 Jan 2013 Arduino Distance Meter
  24. 22 Jan 2013 Arduino Digital Clock and Date
  25. 31 Jan 2013 Arduino Digital Clock and Date 8x2 LCD
  26. Feb 2013 LCD and Backpack
  27. Feb 2013 7 Segment Serial Clock Sparkfun. Distance Sensor with "newping" library
  28. Feb 2013 Lelo Remote
  29. 01/03/2013 Arduino Adafruit 7 Seg Digital Clock with RTC and backpack 
  30. Arduino Frequency Meter 26/03/2013
  31. Another RC  Car controlled by Arduino 06/04/2013
  32. My quadcopter project update 25 April 2013
  33. My Aqua Quad Copter Flying 26 April 2013enlightened
  34. Another monster RC truck;strong one! 11July2013cool
  35. X-Frame Quad Copter 31 July 2013cool
  36. Arduino GSM Sheild added.28/8/2013
  37. 1.8inch TFT screen 13/09/2013cool
  38. 04/11/2014 added PID Soldering Iron Control
  39. Added bluetooth servo control 04/11/2014
  40. ESP8266 first try.16/03/2015
  41. Arduino Uno Quadcopter 19 May 2015
  42. IOT WemosD1 Amp Meter

 

 


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Not my own code, but I changed the code to display on LCD. I also changed the refresh setting.

I also kept the same R1 and R2 values in the code, but my practical voltage divider circuit consist of R1 = 10K and R2 is a 10 K pot, therefore I could calibrate the potentiometer to accept any voltage from 0V to more than 40VDC. It was just trial and error and is not a fixed given. 

// variables for input pin and control LED

// voltage devider R1 = 10K and R2 Pot 10K then calibrate pot. 

// leave values R1 and R2 as per code!!

// will measure from 0V to more than 50VDC once calibrated with pot.

// you may vary your own combinations

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

  int analogInput = 1;

  int LEDpin = 13;

  int prev = LOW;

  int refresh = 500;

  float vout = 0.0;

  float vin = 0.0;

  float R1 = 50000.0;    // !! resistance of R1 !! Not practical

  float R2 = 4300.0;     // !! resistance of R2 !! Not practical

// variable to store the value 

  int value = 0;

void setup(){

  // declaration of pin modes

  pinMode(analogInput, INPUT);

  pinMode(LEDpin, OUTPUT);

  // begin sending over serial port

  Serial.begin(9600);

  lcd.begin(16, 2);                   // set the lcd dimension

  lcd.clear(); 

}

void loop(){

  // read the value on analog input

  value = analogRead(analogInput);

  //Serial.print("value=");

  //Serial.println(value);

  if (value >= 1023) {

    lcd.clear();

    lcd.setCursor(0,1);

    Serial.println("MAX!!");

    lcd.print("      MAX!!");

    delay(refresh);

    return;

  }

  else if (value <= 0) {

    lcd.clear();

    lcd.setCursor(0,2);

    Serial.println("MIN!!");

    lcd.print("      MIN!!");

    delay(refresh);

    return;

  }

  // blink the LED

  if (prev == LOW) {

    prev = HIGH;

  } else {

    prev = LOW;

  }

  digitalWrite(LEDpin, prev); 

  // print result over the serial port

  // also print result on LCD

  vout = (value * 5.0) / 1024.0;

  vin = vout / (R2/(R1+R2));

   //Serial.print("vout=");

  //Serial.println(vout);

   Serial.print(vin);

  lcd.clear();

  lcd.setCursor(6,0);

  lcd.print(vin);

  Serial.println(" volt");

  lcd.setCursor(5,1);

  lcd.print(" VOLT");

  // sleep...

  delay(refresh);

}

Here is a picture of my LCD 8x2 version:


 

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