Impossible to set a variable to zero

Using Arduino Programming Questions
#1

I have problems resetting my variable AS to zero as soon as in reaches the value 100
This a part of my code. Thx in advance for your help!

 x = analogRead (0);
  lcd.setCursor(10,1);
    if (x < 60) {    //rechts
     ++AS;
     lcd.setCursor(12,0);
     lcd.print(AS);
     if (AS > 100)  AS = 0;
     delay(100);
#2

You set AS to 0, and then increment it before printing it. How do you expect to ever see 0 printed?

#3

@Dashi, thx I tried that to does not work.

@PaulS that is true but that would give me a 1 for AS but in my example AS increments over 100 and never resets to zero

#4

Again this is why you are told to post all your code. The problem is not where you think it is!

Mark

#5

sorry , Mark,

this is the whole code. It’s a bit of a mess because I’m experimenting

 int x;
  int SG = 20;
  long AS = 20;
  int y;

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

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.setCursor(0,0);
  lcd.print("SG");
  lcd.setCursor(9,0);
  lcd.print("AS");
  lcd.setCursor(0,1);
  lcd.print("Key ?");
   
}

void loop() {
  
  x = analogRead (0);
  lcd.setCursor(10,1);
    if (x < 60) {    //rechts
     ++AS;
     lcd.setCursor(12,0);
     lcd.print(AS);
     if (AS > 100)  AS = 0;
     delay(100);
     
     
  }
  else if (x < 200) {
    lcd.print ("Up    ");// stap vooruit
  }
  else if (x < 400){
    lcd.print ("down");//stap achteruit
  }
  else if (x < 600){ // links
      ++SG; 
     lcd.setCursor(4,0);
     lcd.print(SG);
     delay(100);
      }
  else if (x < 800){
    lcd.print ("start");//uitvoering AS * SG
  }
   
}
#6 
    if (x < 60) {    //rechts
     ++AS;                        // AS is incremented (after a previous clear)
     lcd.setCursor(12,0);
     lcd.print(AS);             // and then printed
     if (AS > 100)  AS = 0;  // AS is cleared 
                                        // move the lcd.print to here instead
     delay(100);
  }
#7

I think you’re seeing residual characters on the LCD. When 100 is sent to the LCD, then AS gets reset to 0 (or 1), the next print only prints a single character (e.g. 1) and the two zeroes from the 100 remain.

Try something like

  x = analogRead (0);
  lcd.setCursor(10,1);
    if (x < 60) {    //rechts
     ++AS;
     lcd.setCursor(12,0);
     lcd.print(AS);
     lcd.print("  ");
     if (AS > 100)  AS = 0;
     delay(100);
#8

That was it Jack, thx a lot.

It was so confusing it looked like it kept on counting!

Guido

#9

Geyst:
That was it Jack, thx a lot.

It was so confusing it looked like it kept on counting!

Guido

You're welcome. I know ... did the same thing once!

#10