why my arduino doesnt recognize the characters?

Question

I have a problem with my Bluetooth module on my Arduino, I am trying to do a door that opens with a button in an application in the phone but when I press the button in the app the door doesn't move.

#include <SoftwareSerial.h>
#include <Servo.h>
int mover;
int mover2;
Servo servoMotor1;
Servo servoMotor2;
char rxChar;
SoftwareSerial BTserial(10, 11);
void setup(){
  Serial.begin(9600);
  Serial.println("Bluetooth test program");
pinMode (4,INPUT);//Fin de carrera 1
pinMode (2,INPUT);//Fin de carrera 2
mover=90; //0 Abrir 180 Cerrar 60-120 Velocidades
mover2=150;//motor Cerradura
servoMotor1.attach(8);//Motor Pin8
servoMotor2.attach(9);//Motor Pin9
BTserial.begin(9600);
BTserial.println("Bluetooth test program");
}
void loop() {
 int lectura; 
 int lectura2;
  servoMotor1.write(mover);
  servoMotor2.write(mover2);
  lectura=digitalRead(4);//fin de carrera
  lectura2=digitalRead(2);//fin de carrera
if (Serial.available())
   {
      BTserial.write(Serial.read());
      
   }
   if (BTserial.available())
   {
      Serial.write(BTserial.read());
      char rxChar = BTserial.read();
   }
   if(rxChar=='a'){
   Serial.print("60 Grados");
   mover=60;
   }
   if(rxChar=='b'){
   Serial.print("120 Grados");
   mover=120;
   }
  if (lectura==LOW and mover==120){
    mover=90;//motor frena
    mover2=30;//Motor Cerradura Cerrado
  }
  if (lectura2==LOW and mover==60){
    mover=90;//motor frena
    
  }
  }

when I press the button the console returns "⸮"

Wrong baud? You are seining a non printable character? And why are you reading 2 characters from `BTserial`, if you only guaranteed that you have at least 1 character to read? — gre_gor, Nov 17 '21 at 22:08

mmixLinus · Answer 1 · 2021-11-18T08:56:42.950

This line is wrong: char rxChar = BTserial.read(); because you are declaring a local rxChar and assigning the read character to it. But, because it is local (inside { } ) its value will be lost. And because you also have a global rxChar (line 7: char rxChar;) that is unassigned, you will be using that value everywhere else.

Also, as mentioned you are reading from BTSerial twice.

You can fix the problem by simply removing "char" in the line mentioned, so rxChar will refer to the global declaration, and
perform only one read: rxChar = BTserial.read(); Serial.write(rxChar);

why my arduino doesnt recognize the characters?

1 Answers1