HC-05 sends endless println messages and does not respond

Question

I'm making an RC car for my school project, and this is my first time writing codes.

I'm using Arduino Uno, L293D motor shield, and HC-05 for this project.

I was following the guide from https://blog.miguelgrinberg.com/post/building-an-arduino-robot-part-ii-programming-the-arduino, and I couldn't properly communicate with the Arduino through bluetooth connection.

Everything works fine with the sketch below:

#include <SoftwareSerial.h>
SoftwareSerial BTSerial(6,7);

void setup()
{
   BTSerial.begin(9600);
}

void loop()
{
   if (BTSerial.available() > 0) {
       char ch = BTSerial.read();
       BTSerial.print("Received: ");
       BTSerial.println(ch);
       if (ch == 'a') {
           digitalWrite(9, HIGH);
       }
       else {
           digitalWrite(9, LOW);
       }
   }
}

I can turn the LED on and off with my android phone with this sketch, but if I include definitions for motors in the sketch, the arduino continuously sends println messages to my phone and it does not respond to my command.

#include <SoftwareSerial.h>
#include <AFMotor.h>

SoftwareSerial BTSerial(6,7);
AF_DCMotor Motor1(1);
AF_DCMotor Motor2(2);
AF_DCMotor Motor3(3);
AF_DCMotor Motor4(4);

void setup()
{
   BTSerial.begin(9600);
}

void loop()
{
   if (BTSerial.available() > 0) {
       char ch = BTSerial.read();
       BTSerial.print("Received: ");
       BTSerial.println(ch);
       if (ch == 'C') {
           Motor1.setSpeed(255);
           Motor1.run(BACKWARD);
           Motor2.setSpeed(255);
           Motor2.run(BACKWARD);
           Motor3.setSpeed(255);
           Motor3.run(BACKWARD);
           Motor4.setSpeed(255);
           Motor4.run(BACKWARD);
       }
       if (ch == 'D') {
           Motor1.setSpeed(0);
           Motor1.run(BRAKE);
           Motor2.setSpeed(0);
           Motor2.run(BRAKE);
           Motor3.setSpeed(0);
           Motor3.run(BRAKE);
           Motor4.setSpeed(0);
           Motor4.run(BRAKE);
       if (ch == 'E') {
           digitalWrite(9, HIGH);
       }
       if (ch == 'F') {
           digitalWrite(9, LOW);
       }
       }
   }
}

Why is this happening and how do I fix it? Please help.

(For attachments) I did not connect to the motors; they work fine with serial connection to my laptop with modified sketch, but apparently it does not work with bluetooth commands.enter image description here

Ashish Kumar Ashish Kumar · Accepted Answer · 2018-05-23T08:19:47

#include <SoftwareSerial.h>
#include <AFMotor.h>

SoftwareSerial BTSerial(6,7);
AF_DCMotor Motor1(1);
AF_DCMotor Motor2(2);
AF_DCMotor Motor3(3);
AF_DCMotor Motor4(4);

void setup()
{
   BTSerial.begin(9600);
}

void loop()
{
   while (BTSerial.available()) {
       delay(10)  //delay for giving time to the read buffer
       char ch = BTSerial.read();
       BTSerial.print("Received: ");
       BTSerial.println(ch);
       switch(ch){
       case 'C':
                Motor1.setSpeed(255);
                Motor1.run(BACKWARD);
                Motor2.setSpeed(255);
                Motor2.run(BACKWARD);
                Motor3.setSpeed(255);
                Motor3.run(BACKWARD);
                Motor4.setSpeed(255);
                Motor4.run(BACKWARD);
                break;
       case 'D':
                Motor1.setSpeed(0);
                Motor1.run(BRAKE);
                Motor2.setSpeed(0);
                Motor2.run(BRAKE);
                Motor3.setSpeed(0);
                Motor3.run(BRAKE);
                Motor4.setSpeed(0);
                Motor4.run(BRAKE);
                break;
       case 'E':
               digitalWrite(9, HIGH);
               break;
       case 'F':
               digitalWrite(9, LOW);
               break;
     }
     break;
  }
}

Try this and tell is this working accordingly or not.

Also, you can use an android app available on playstore for controlling. I think you will like this app got really great feature for making different projects.

https://play.google.com/store/apps/details?id=invootech.ashish.anduino_connect

HC-05 sends endless println messages and does not respond

1 Answers