I can't convert string to int

[qatalin]

Hi,

I have a problem converting a string into an integer or a float. It shows me that I find 0.00.

You can help me

I am attaching an image with the code and the serial monitor below!

Thank you very much!

[Idahowalker]

is how I do it x_eData.RM0 = String(px_message.payload).toFloat(); and x_eData.RM1 = String(px_message.payload).toInt();

An attached image with code is useless. Posted code in code tags now that is something useful.

Did you happen to skip the reading of,

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See also FAQ - Arduino Forum for general rules on forum behaviour and etiquette. Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is fru…

If so it might be a good time to review the thing.

[killzone_kid]

what is the source string content before you do all the parsing?

[qatalin]

#include<SoftwareSerial.h>
SoftwareSerial SUART(0, 2); 
int value;
void setup()
{
  Serial.begin(9600);
  SUART.begin(9600);
  Serial.println("Process start");
  
}

void loop()
{

  SUART.print('r');
  Serial.println( "Current sensor value reading!");
  delay(2000);
 
  while(SUART.available() > 0)
  {
     String s = SUART.readString();
     s.remove(s.length() - 1);
     s.remove(s.length() - 2);
     s.remove(0,2);
     s.replace(" ", "");
     Serial.println(s);
     value = s.toInt();
     float real_value = value*0.75;
     Serial.println(real_value);
     
     
     }
  delay(10*1000);
  } 

This is my code.  The source of sting is a value of a sensor

[Idahowalker]

@qatalin

Serial.println(s);

What does the serial print show?

@qatalin

delay(10*1000);

Really? A actual delay() that long? Your program comes to a stop at this point and does nothing else but delay, delay, delay.

multi things

Demonstration code for several things at the same time

NOTE for newcomers. The demo is entirely contained in this Post and Reply #1. There is no need to read further unless you are interested. ...added 25Sep2014 There have been a few occasions recently where newcomers seemed to have difficulty applying the "blink without delay" and "state" concepts to a sketch that is intended to manage a number of concurrent actions. Its very time consuming to respond with suitable code examples - particularly as every case is a little different. I have prepared…

[qatalin]

this is what serial print show

[qatalin]

@Idahowalker

A actual delay() that long?

Yes, the sensor give value from 10 sec to 10 sec

[Idahowalker]

28 looks like an int.

[qatalin]

it a string. That i want to use toInt syntax.

[Idahowalker]

@qatalin

float real_value = value*0.75;

And try the math like this

float real_value = (float)value*0.75;

[qatalin]

ok. I will try

[Idahowalker]

@qatalin

value = s.toInt();

It is an integer after this point.

[qatalin]

it shoud be, but the result of :

@qatalin

float real_value = value*0.75;

is 0.00.

i tried what you suggest:

@Idahowalker

float real_value = (float)value*0.75;

but same result, 0.00.

[Idahowalker]

Oh, I see.

Serial Input Basics - updated

Continued from previous Post Receiving numbers rather than text So far the examples have assumed you want to receive text. But perhaps you want to send a number or maybe a mix of text and numbers. Example 4 - Receiving a single number from the Serial Monitor The simplest case is where you want to type a number into the Serial Monitor (I am assuming you have line-ending set to newline). Let's assume you want to send the number 234. This is a variation on Example 2 and it will work with any in…

receive the entire message before doing math on the message.

Did you try this

while(SUART.available() > 0)
  {
     String s = SUART.readString();
     s.remove(s.length() - 1);
     s.remove(s.length() - 2);
     s.remove(0,2);
     s.replace(" ", "");
     Serial.println(s);
     value = s.toInt();
     float real_value = value*0.75;
     Serial.println(real_value);
     
     
     }
s=100;
Serial.print( "s " );
Serial.print ( s );
real_value = float(s)*.075f;
Serial.print( " real_value " );
Serial.print (real_value,6 );
Serial.println(); <<<????? does it print a float? If so then you are receiving the serial incorrectly.
delay(10000);
}

[qatalin]

@Idahowalker

oes it print a float? If so then you are receiving the serial incorrectly.

yes, it's 7.500000.

What i can do in this case?

[Idahowalker]

You could read how to send and receive serial info,

serial input basics

Serial Input Basics - updated

Continued from previous Post Receiving numbers rather than text So far the examples have assumed you want to receive text. But perhaps you want to send a number or maybe a mix of text and numbers. Example 4 - Receiving a single number from the Serial Monitor The simplest case is where you want to type a number into the Serial Monitor (I am assuming you have line-ending set to newline). Let's assume you want to send the number 234. This is a variation on Example 2 and it will work with any in…

here is a function I use to receive serial, perhaps it will give a clue or not

void fReceiveSerial_LIDAR( void * parameters  )
{
  char OneChar;
  char *str;
  str = (char *)ps_calloc(300, sizeof(char) ); // put str buffer into PSRAM
  bool BeginSentence = false;
  sSerial.reserve ( StringBufferSize300 );
  for ( ;; )
  {
    EventBits_t xbit = xEventGroupWaitBits (eg, evtReceiveSerial_LIDAR, pdTRUE, pdTRUE, portMAX_DELAY);
    if ( LIDARSerial.available() >= 1 )
    {
      while ( LIDARSerial.available() )
      {
        OneChar = LIDARSerial.read();
        if ( BeginSentence )
        {
          if ( OneChar == ‘>’)
          {
            if ( xSemaphoreTake( sema_ParseLIDAR_ReceivedSerial, xSemaphoreTicksToWait10 ) == pdTRUE )
            {
              xQueueOverwrite( xQ_LIDAR_Display_INFO, ( void * ) &sSerial );
              xEventGroupSetBits( eg, evtParseLIDAR_ReceivedSerial );
              //
            }
            BeginSentence = false;
            break;
          }
          sSerial.concat ( OneChar );
        }
        else
        {
          if ( OneChar == ‘<’ )
          {
            sSerial = “”; // clear string buffer
            BeginSentence = true; // found begining of sentence
          }
        }
      } //  while ( LIDARSerial.available() )
    } //if ( LIDARSerial.available() >= 1 )
    xSemaphoreGive( sema_ReceiveSerial_LIDAR );
  }
  vTaskDelete( NULL );
} //void fReceiveSerial_LIDAR( void * parameters  )

The function checks if there is anything in the serial buffer. If there is then pop off the serial buffer and push it to a storage location. The functions checks for a sentence begin and a sentence end. When the sentence end comes it sends the completed received data off to have work done on the complete received data. The function follows the basics of receiving serial.

[johnwasser]

@qatalin

     Serial.println(s);
     value = s.toInt();
     float real_value = value*0.75;

Could you add a line?

     Serial.println(s);
     value = s.toInt();
     Serial.println(value);  // See if the .toInt() is returning zero.
     float real_value = value*0.75;

[killzone_kid]

@johnwasser

Could you add a line?

it will be 0

[StefanL38]

run this code-version which does output everything after each processing-step
The processed string has a leading and trailing "#" to clearly show what is inside the string

#define dbg(myFixedText, variableName) \
  Serial.print( F(#myFixedText " "  #variableName"=") ); \
  Serial.println(variableName);

#define dbgi(myFixedText, variableName,timeInterval) \
  do { \
    static unsigned long intervalStartTime; \
    if ( millis() - intervalStartTime >= timeInterval ){ \
      intervalStartTime = millis(); \
      Serial.print( F(#myFixedText " "  #variableName"=") ); \
      Serial.println(variableName); \
    } \
  } while (false);

#include<SoftwareSerial.h>
SoftwareSerial SUART(0, 2);
int value;
void setup()
{
  Serial.begin(9600);
  SUART.begin(9600);
  Serial.println("Process start");

}

void loop()
{
  SUART.print('r');
  Serial.println( "Current sensor value reading!");
  delay(2000);

  while (SUART.available() > 0)
  {
    String s = SUART.readString();
    dbg("1:", s);

    s.remove(s.length() - 1);
    dbg("2:", s);

    s.remove(s.length() - 2);
    dbg("3:", s);

    s.remove(0, 2);
    dbg("4:", s);
    s.replace(" ", "");
    dbg("5:", s);

    Serial.print("#");
    Serial.print(s);
    Serial.println("#");

    value = s.toInt();
    dbg("6:", value);

    float real_value = value * 0.75;
    dbg("7:", real_value);
        //Serial.println(real_value);
  }
  delay(10 * 1000);
}

best regards Stefan

[StefanL38]

by the way using IO-pin 0 for the software-serial is a bad idea on Ardiuno Uno/Mega
IO-pins 0 and 1 are used for serial.

best regards Stefan