I can't convert string to int

[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);
}