control speed of DC motor with bluetooth

Using Arduino Motors, Mechanics, Power and CNC
#1

Hi all
I’m making RC car, controlled by accelometer. I sent sensor value to slave arduino with bluetooth and I checked the value with my Serial monitor. But motor just don’t move at all. I used MPU 6050, L298N and HC-06
master code:

#include <SoftwareSerial.h>
#include <Wire.h>
#include <SPI.h>
SoftwareSerial btSerial(8,9);
const int MPU=0x68;
int AcX, AcY, AcZ, Tmp, GyX, GyY, GyZ;
void get6050();
int xpos;
int ypos;
void setup()
{
  Serial.begin(9600);
  btSerial.begin(9600); 
  Wire.begin();
  Wire.beginTransmission(MPU);  
  Wire.write(0x6B);
  Wire.write(0);
  Wire.endTransmission(true);
}
void loop()
{
    get6050();
    xpos=map(AcX,-16383,16383,80,255);
    ypos=map(AcY,-16383,16383,0,180);
    btSerial.println(xpos);
    Serial.print("xpos=");
    Serial.println(xpos);
    delay(100);
}
void get6050(){
  Wire.beginTransmission(MPU);
  Wire.write(0x3B);
  Wire.endTransmission(false);
  Wire.requestFrom(MPU,14,true);
  AcX=Wire.read()<<8|Wire.read();
  AcY=Wire.read()<<8|Wire.read();
  AcZ=Wire.read()<<8|Wire.read();
  Tmp=Wire.read()<<8|Wire.read();
  GyX=Wire.read()<<8|Wire.read();
  GyY=Wire.read()<<8|Wire.read();
  GyZ=Wire.read()<<8|Wire.read();
}

and slave code:

#include <SoftwareSerial.h>
SoftwareSerial BTSerial(8,9);
int val;
void setup() {
  // put your setup code here, to run once:
BTSerial.begin(9600);
Serial.begin(9600);
pinMode(2,OUTPUT);
pinMode(4,OUTPUT);
}
void loop() {
  digitalWrite(2,HIGH);
  digitalWrite(4,LOW);
  if(BTSerial.available()){
  val=BTSerial.read();
  Serial.write(val);
    analogWrite(3,val);
  }
  
}

code is so simple cuz i try to control one wheel first. pin 3 of slave arduino control the speed of DC motor. When I put those code to each arduino, slave arduino prints right sensor value at Serial monitor but motor doesn’t move and just make a sound like ‘beeeeeeeeeep’. I can control the speed when I use just one arduino and no communication. I need your help to control motor when I use bluetooth communication!

#2

Does BTSerial.read() return a string or an integer?

#3

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data. There is also a parse example to illustrate how to extract numbers from the received text.

...R

#4