2 DC motors & 1 servo for steering rc car - bluetooth

Question

im working on an RC car project and im using 2 DC motors as a rear wheels ,one servo motor on front for steering with a nano arduino as a microcontroller, HC 06-slave bluetooth receiver, and L298N module for Fwd/Rev and PWM. for my transmitter im using nano arduino a joystick and HC-06 master.
i need my joystick Y axis to drive fwd/rev and X axis for steering. i manged to test the servo alone for X axis steering and it worked, also when tested the code for FWD/REV on Y axis it worked.. however when i combine my code it doesn't work my servo starts shaking and my DC motors start responding to x and y!!
can someone help me pls.
here are the codes im using:
Master code (transmitter);
// == MASTER DEVICE - Joystick ==
//int xAxis, yAxis;
void setup() {
Serial.begin(9600); // Default communication rate of the Bluetooth
module
}
void loop() {
xAxis = analogRead(A0); // Read Joysticks X-axis
yAxis = analogRead(A1); // Read Joysticks Y-axis
// Send the values via the serial port to the slave HC-05 Bluetooth
device
Serial.write(xAxis/4); // Dividing by 4 for converting from 0 -
1023 to 0 - 256, (1 byte) range
Serial.write(yAxis/4);
delay(20);
}
slave code (servo only);
#include <Servo.h>
Servo myServo;
int yAxis;
void setup() {
myServo.attach(3);
Serial.begin(9600); // Default communication rate of the Bluetooth
module
}
void loop() {
yAxis = 510 / 4;
// Read the incoming data from the Joystick, or the master
Bluetooth device
if(Serial.available() > 0){ // Checks whether data is comming from
the serial port
yAxis = Serial.read(); // Reads the data from the serial port
}
delay(10);
myServo.write(yAxis);
delay(10);
}
slave code for DC motors FWD/REV;
#include <Servo.h>
#define enA 9
#define in1 4
#define in2 5
#define enB 10
#define in3 6
#define in4 7
//int servoPin = 3;
int xAxis;
unsigned int x = 0;
unsigned int y = 0;
int motorSpeedA = 0;
int motorSpeedB = 0;
//Servo Servo1;
void setup() {
pinMode(enA, OUTPUT);
pinMode(enB, OUTPUT);
pinMode(in1, OUTPUT);
pinMode(in2, OUTPUT);
pinMode(in3, OUTPUT);
pinMode(in4, OUTPUT);
Serial.begin(9600); // Default communication rate of the Bluetooth module
// Servo1.attach(servoPin);
}
void loop() {
// Default value - no movement when the Joystick stays in the center
x = 510 / 4;
y = 510 / 4;
// Read the incoming data from the Joystick, or the master Bluetooth device
while (Serial.available() >= 2) {
x = Serial.read();
// delay(10);
// y = Serial.read();
}
delay(10);
// Convert back the 0 - 255 range to 0 - 1023, suitable for motor control code below
xAxis = x*4;
// yAxis = y*4;
// Y-axis used for forward and backward control
if (xAxis < 470) {
// Set Motor A backward
digitalWrite(in1, HIGH);
digitalWrite(in2, LOW);
// Set Motor B backward
digitalWrite(in3, HIGH);
digitalWrite(in4, LOW);
// Convert the declining Y-axis readings for going backward from 470 to 0 into 0 to 255 value for the PWM signal for increasing the motor speed
motorSpeedA = map(xAxis, 470, 0, 0, 255);
motorSpeedB = map(xAxis, 470, 0, 0, 255);
}
else if (xAxis > 550) {
// Set Motor A forward
digitalWrite(in1, LOW);
digitalWrite(in2, HIGH);
// Set Motor B forward
digitalWrite(in3, LOW);
digitalWrite(in4, HIGH);
// Convert the increasing Y-axis readings for going forward from 550 to 1023 into 0 to 255 value for the PWM signal for increasing the motor speed
motorSpeedA = map(xAxis, 550, 1023, 0, 255);
motorSpeedB = map(xAxis, 550, 1023, 0, 255);
}
// If joystick stays in middle the motors are not moving
else {
motorSpeedA = 0;
motorSpeedB = 0;
}
if (motorSpeedA < 70) {
motorSpeedA = 0;
}
if (motorSpeedB < 70) {
motorSpeedB = 0;
}
analogWrite(enA, motorSpeedA); // Send PWM signal to motor A
analogWrite(enB, motorSpeedB); // Send PWM signal to motor B
}
i want to combine them so one of the axis is for DC motors FWD/REV and the other axis is for servo motor right/left.

Answer 1

You must be more explicit with the data you send.
Don't send x=20,y=30 as char[2]={20,30}.
A minimum would be char[4]={'x',20,'y',30}.
Then you will check that you receive complete datagram of 4 char, and then you can check that you don't confuse x with y.