Set variable between specific values

system · April 30, 2009, 10:01pm

Hello,

Is it possible to set a variable between specific values?

for example a value only from 0 to 255?

Now I use the unsigned int but I would like to set a certain maximum value.

Thanks in advance.

system · April 30, 2009, 10:47pm

For 0 - 255 the best would be to use a byte. But then you could assign the value -1, and get the unexpected result 255.

I've made a library for this, it's called Constrain

Constrained example(10,0,255);

example is 10, and can never go below 0, or above 255

system · April 30, 2009, 10:52pm

Great This is just what I need. Thanks

system · April 30, 2009, 11:04pm

I get this error:

"3: error: invalid preprocessing directive #inlcude In function 'void loop()':"

I got this error after adding the #inlcude <Constrain.h> library
What does it exactly mean?

system · April 30, 2009, 11:07pm

http://www.arduino.cc/playground/Code/Constrain#Download

Just PM me for a more thourough explanation. If you feel you need one, that is.

system · April 30, 2009, 11:09pm

I typed include the wrong way......... Now it is working Thanks

system · April 30, 2009, 11:13pm

I typed include the wrong way

I constantly write "inlcude" >:(

I think it is because inl are all on the right hand when typing.

I've spent some time debugging that typo.
At least I'm not alone

system · April 30, 2009, 11:14pm

Another error:

In function 'void loop()':
error: cannot convert 'Constrained' to 'int' for argument '2' to 'void analogWrite(uint8_t, int)'

Variables:

Constrained PWMval_Left( 0 , 0 , 255 );
Constrained PWMvalRev_Left( 0 , 0 , 255 );
Constrained PWMval_Right( 0 , 0 , 255 );
Constrained PWMvalRev_Right( 0 , 0 , 255 );

The error is on this line:

analogWrite (PWMpin_Left, PWMvalRev_Left);

Changing Constrained to Constrained also gives the same error.

system · April 30, 2009, 11:26pm

analogWrite (PWMpin_Left.value, PWMvalRev_Left.value);

It is a bit poorly documented. Will fix that soon.

system · April 30, 2009, 11:29pm

Another one on the same line:

In function 'void loop()':
error: request for member 'value' in 'PWMpin_Left', which is of non-class type 'int'

Just see me as a beta tester of your library

system · April 30, 2009, 11:39pm

Try it now: http://www.arduino.cc/playground/uploads/Code/Constrain.zip

analogWrite ((byte)PWMpin_Left, (int)PWMvalRev_Left);

[edit]I think:
analogWrite ((int)PWMpin_Left.value, (byte)PWMvalRev_Left.value); would solve your problem without downloading the new Constrain.[/edit]

Just see me as a beta tester of your library

Yes, thank you!

system · April 30, 2009, 11:46pm

Now I get this one:

In function 'void loop()':
error: invalid cast from type 'Constrained' to type 'int'

on this line:

analogWrite ((byte)PWMpin_Left, (int)PWMvalRev_Left);

using these variables:

Constrained PWMvalRev_Left( 0 , 0 , 255 );
int PWMpin_Left = 4;

system · April 30, 2009, 11:49pm

Is that with version 1.1?

Could you post your code?

Strange behaviour.

Thank you for your patience

[edit]I compiles here. Strange. Maybe you could try to download the Constrain library again :)[/edit]

system · April 30, 2009, 11:57pm

 #include <SNESpad.h>
 #include <Constrain.h>

SNESpad nintendo = SNESpad();
int state = 0;

//Motor Control
Constrained<byte> PWMval_Left( 0 , 0 , 255 );
Constrained<byte> PWMvalRev_Left( 0 , 0 , 255 );
int DigPin1_Left = 2;
int DigPin2_Left = 3;
int PWMpin_Left = 4;
char State1_Left = HIGH;
char State2_Left = LOW;

Constrained<byte> PWMval_Right( 0 , 0 , 255 );
Constrained<byte> PWMvalRev_Right( 0 , 0 , 255 );
int DigPin1_Right = 5;
int DigPin2_Right = 6;
int PWMpin_Right = 7;
char State1_Right = HIGH;
char State2_Right = LOW;

void setup() {
  
  Serial.begin(9600);
  
  // Attach motors
  pinMode(DigPin1_Left, OUTPUT); 
  pinMode(DigPin2_Left, OUTPUT);
  pinMode(DigPin1_Right, OUTPUT); 
  pinMode(DigPin2_Right, OUTPUT);
  
}

void loop() {

  // Servo Control SNES PAD
  state = nintendo.buttons();
 
    digitalWrite(DigPin1_Left, State1_Left );
    digitalWrite(DigPin2_Left, State2_Left); 
    digitalWrite(DigPin1_Right, State1_Right);
    digitalWrite(DigPin2_Right, State2_Right); 
    
    if (PWMval_Left = 0)
    {
    analogWrite ((byte)PWMpin_Left, (int)PWMvalRev_Left); 
    //analogWrite (PWMpin_Left.value, PWMvalRev_Left.value);
    analogWrite (PWMpin_Right.value, PWMvalRev_Right.value);
    }
    else
    {
    analogWrite (PWMpin_Left, PWMval_Left);
    analogWrite (PWMpin_Right, PWMval_Right);
    }
 
  if (state & SNES_UP && (PWMval_Left >= 0 && PWMval_Left < 250) && PWMvalRev_Left == 0) 
  {
    State1_Left = HIGH;
    State2_Left = LOW;
    State1_Right = HIGH;
    State2_Right = LOW;
    
    PWMval_Left = PWMval_Left + 2;
    PWMval_Right = PWMval_Right + 2;
    
    Serial.print(" ");
    Serial.print(PWMval_Left);
    Serial.print(" ");
    Serial.print(PWMval_Right);
    
    }}

Here's the code I use. I have tried it with the newest version of the library.

Maybe you can edit my code so I can comply it over here?

I don't mind that I have to be patient. I think its a good and very useful library

system · May 1, 2009, 12:27am

Version 1.3: http://www.arduino.cc/playground/uploads/Code/Constrain.zip

//#include <SNESpad.h>
#include <Constrain.h>

//SNESpad nintendo = SNESpad();
int state = 0;

//Motor Control
Constrained PWMval_Left( 0 , 0 , 255 );
Constrained PWMvalRev_Left( 0 , 0 , 255 );
int DigPin1_Left = 2;
int DigPin2_Left = 3;
int PWMpin_Left = 4;
char State1_Left = HIGH;
char State2_Left = LOW;

Constrained PWMval_Right( 0 , 0 , 255 );
Constrained PWMvalRev_Right( 0 , 0 , 255 );
int DigPin1_Right = 5;
int DigPin2_Right = 6;
int PWMpin_Right = 7;
char State1_Right = HIGH;
char State2_Right = LOW;

void setup() {

Serial.begin(9600);

// Attach motors
pinMode(DigPin1_Left, OUTPUT);
pinMode(DigPin2_Left, OUTPUT);
pinMode(DigPin1_Right, OUTPUT);
pinMode(DigPin2_Right, OUTPUT);

}

void loop() {

// Servo Control SNES PAD
//state = nintendo.buttons();

digitalWrite(DigPin1_Left, State1_Left );
digitalWrite(DigPin2_Left, State2_Left);
digitalWrite(DigPin1_Right, State1_Right);
digitalWrite(DigPin2_Right, State2_Right);

if (PWMval_Left = 0)
{
analogWrite (PWMpin_Left, (int)PWMvalRev_Left);
analogWrite (PWMpin_Right, (int)PWMvalRev_Right);
}
else
{
analogWrite (PWMpin_Left, (int)PWMval_Left);
analogWrite (PWMpin_Right, (int)PWMval_Right);
}
if (/state & SNES_UP &&/ (PWMval_Left >= (byte)0 && PWMval_Left < (byte)250) && PWMvalRev_Left == (byte)0)
{
State1_Left = HIGH;
State2_Left = LOW;
State1_Right = HIGH;
State2_Right = LOW;

PWMval_Left += 2;
PWMval_Right += 2;

Serial.print(" ");
Serial.print((int)PWMval_Left);
Serial.print(" ");
Serial.print((int)PWMval_Right);

}
}

system · May 1, 2009, 2:40pm

I've pasted the code into a new file and still receive a error:

In function 'void loop()':
error: invalid cast from type 'Constrained' to type 'int'

I've installed the latest version (1.3) of the library. I've deleted the old folder in Hardware --> library copied the 1.3 version into the folder and restarted Arduino 0015. I assume this is the right way to install the library?

What Arduino version do you use? I use 0015 because I have a Arduino Mega. Can this be the reason?

Best regards.

system · May 4, 2009, 7:21pm

Hello,

Here (http://arduino.pastebin.com/m460a66f1) is all the code I use.

I use Arduino 0015 (see my previous post).

Best regards.

system · May 4, 2009, 7:39pm

I see. You've used a pretty old constrain.h

I'm glad this might be it. Started to worry.

http://arduino.pastebin.com/f3918921a
Is what your .h should look like.

system · May 4, 2009, 8:49pm

Thats strange :o , I've always installed the most recent version I thought.

I'll test is as soon as possible and let you know.

Thanks

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