Actions
Forum Thread Details
  • State Suggested Answer
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 418 subscribers
  • Views 735 views
  • Users 0 members are here
Related

problem with digital input pins in controlling its output pins.. we really need suggestions...

e14 Contributor

i have 2 digital input pins(pin16 & pin17 actually i need 4)

just to test if it really gonna work.What i did is that

i just give 5volts or high to these pins as input data

but what happened there is that the 2 digitalOutput pins respectively

seems doesnt do to the conditions i gave it seems it can affect the other condition.

 

 

here is a part of my code .

 

  if (digitalRead(16) == LOW )

    { digitalWrite(ledPin7,HIGH);

    }

  if (digitalRead(17) == LOW )

    { digitalWrite(ledPin6,HIGH);

    }

 

  else

    digitalWrite(ledPin7,LOW);

    digitalWrite(ledPin6,LOW);

 

          ,,

          what i really want to do there is that

          just have  4  inputs(that would be 5volts)

          and also give 4  outputs respectively..

 

we really need Ur suggestions  and ideas.. thnx ;d

Parents
  • 0

    I think it might be the way you are building your if...else statements.

     

    Try this way:

     

      if (digitalRead(16) == LOW ) {

         digitalWrite(ledPin7,HIGH);

      }

      else {

         digitalWrite(ledPin7,LOW);

      }

     

      if (digitalRead(17) == LOW ) {

          digitalWrite(ledPin6,HIGH);

        }

      else {

        digitalWrite(ledPin6,LOW);

      }

     

    It's a good idea to always follow every if and else with a { ... } block, that way you know that everything within the { ... } block will be part of the if, or part of the else. The way you had it set up would always set ledPin6 LOW, because without the curly brackets only the first line after "else" is considered to be part of the else block - the next line is just a line that always gets executed.

     

    Hope that helps!

     

    Cheers,

    -Nico

Reply
  • 0

    I think it might be the way you are building your if...else statements.

     

    Try this way:

     

      if (digitalRead(16) == LOW ) {

         digitalWrite(ledPin7,HIGH);

      }

      else {

         digitalWrite(ledPin7,LOW);

      }

     

      if (digitalRead(17) == LOW ) {

          digitalWrite(ledPin6,HIGH);

        }

      else {

        digitalWrite(ledPin6,LOW);

      }

     

    It's a good idea to always follow every if and else with a { ... } block, that way you know that everything within the { ... } block will be part of the if, or part of the else. The way you had it set up would always set ledPin6 LOW, because without the curly brackets only the first line after "else" is considered to be part of the else block - the next line is just a line that always gets executed.

     

    Hope that helps!

     

    Cheers,

    -Nico

Children
  • 0 in reply to ntewinkel

    Yes, Nico, you are right.  The way the sketch was originally written if pin 17 is high then both out puts are driven low in a VERY short amount of time.  My brain was not in the correct level/mode to see it clearly.  I am glad you came along to do it.  It is amazing that I find myself trying to use a "hardware" hammer where a "software" hammer is needed.  Time to regroup.

  • 0 in reply to billabott

    Hi billabott, you're right about that.

     

    If we properly format the original code it becomes very clear:

     

    if (digitalRead(16) == LOW ) {

          digitalWrite(ledPin7,HIGH);

      }

    // else nothing

     

      if (digitalRead(17) == LOW )  {

          digitalWrite(ledPin6,HIGH);

      }

      else

        digitalWrite(ledPin7,LOW);  // because there are no curly brackets, this is the only line that is part of the "else"

     

    // and this always gets executed

    digitalWrite(ledPin6,LOW);

     

    So you can see that ledPin6 is always LOW at the end of this code. ledPin7 is a bit less predictable.

     

    I must be missing part of an earlier conversation - what do you mean by "original processing application" ?

     

    Cheers,

    -Nico

  • 0 in reply to ntewinkel

    Arduino IDE is modified version of the Processing Application  as specified on Processing.org.  (Think Turtle programming)  My question is a carry over tangent from the J.Blum Arduino discussion.

  • 0 in reply to billabott

    Nico

    Well done

     

    One other way is to make them LOW and change them if the button is LOW.

     

        digitalWrite(ledPin7,LOW);

        digitalWrite(ledPin6,LOW);

     

      if (digitalRead(16) == LOW )

        {

            digitalWrite(ledPin7,HIGH);

        }

      if (digitalRead(17) == LOW )

        {

           digitalWrite(ledPin6,HIGH);

        }

     

     

     

    If the LED state was HIGH when the Button input was HIGH, you could simplify it to

    void loop()

    {

          digitalWrite(ledPin7,(digitalRead(16)));

          digitalWrite(ledPin6,(digitalRead(17)));

     

    }

     

    Note : it compiles but I haven't tried it.

     

    Mark

  • 0 in reply to ntewinkel

    thnx nicz!!! image that help  much,, now  i can now proceed to our actual material testing.hehe  i never thought that it would affect ..