Not equal problem

[tom321]

Hi
When I change Voltage on A0, U1 should show same thing but I have all the time zero - 0

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //uno

float V = 0;
int U1;

void setup() {
  pinMode(A0, INPUT);
  Serial.begin(9600);
  lcd.begin(16, 2);
}

void loop() {

  V = analogRead(A0);
  V = V / 1024 * 5.0; 
  
  /////////////////////
  if (V != V)
  {
    U1 = V;
  }
  /////////////////////

  Serial.print("V= ");
  Serial.print(V);
  Serial.print("     U1= ");
  Serial.println(U1);

  lcd.setCursor(6, 1); //Place the cursor at Line 1, Column 6. From here the
  lcd.print(V, 1); //Print the number of val on the LCD
  lcd.print("V");
  delay(100);

}

[Paul_KD7HB]

Analog read return an integer, not a float. Read the documentation!
Paul

[anon73444976]

@tom321

if (V != V)

You sure about that?

[tom321]

not, that why I marked this part

[groundFungus]

How can V be not equal to V?

[tom321]

now is working
Thanks
if (currentV != V)
{
U1 = V;
}

[gfvalvo]

See Reply #2. Don't attempt to compare equality or inequality on float variables.

[tom321]

now is working, with this I have all zeros

int V;

[gfvalvo]

Actually, it doesn't work at all. The variable 'currentV' is undefined in the code you posted. So, it doesn't even compile.

[tom321]

I added also

float currentV;

[anon73444976]

We can't see your code

[gfvalvo]

@gfvalvo

Don't attempt to compare equality or inequality on float variables.

Like I said.

[tom321]

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //uno

float V = 0;
float U1;
float currentV;

void setup() {
  pinMode(A0, INPUT);
  Serial.begin(9600);
  lcd.begin(16, 2);
}

void loop() {

  V = analogRead(A0);
  V = V / 1024 * 5.0; 
  
  /////////////////////
  if (currentV != V)
  {
    U1 = V;
  }
  /////////////////////

  Serial.print("V= ");
  Serial.print(V);
  Serial.print("     U1= ");
  Serial.println(U1);

  lcd.setCursor(6, 1); //Place the cursor at Line 1, Column 6. From here the
  lcd.print(V, 1); //Print the number of val on the LCD
  lcd.print("V");
  delay(100);

}

[anon73444976]

currentV has the value 0.0, as does U1

[tom321]

here you are

[anon73444976]

And after that, you never change the value of currentV

[tom321]

when I changing U1 is following V