Help! Arduino 12v DC tank, one joystick, no buttons need to change code

Projects Programming
1

Need help changing code to be able to make zero point turns. My first arduino serious project With the one joystick I want to be able to have one motor go forward and the other in reverse to make a tight turn when going left or right on joystick. Using Hc-05 master and Hc-06 slave, arduino uno on slave side and nano on master, L298n for motors, 12v 200 rpm gear motors. Slave code in comments. Thanks

/*
Arduino Robot Car Wireless Control using the HC-05 Bluetooth
== SLAVE DEVICE - Arduino robot car ==

/
#define enA 9
#define in1 4
#define in2 5
#define enB 10
#define in3 6
#define in4 7
int xAxis, yAxis;
unsigned int x = 0;
unsigned int y = 0;
int motorSpeedA = 0;
int motorSpeedB = 0;
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
}
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 = x4;
yAxis = y*4;
// Y-axis used for forward and backward control
if (yAxis < 470) {
// Set Motor A backward
digitalWrite(in1, LOW);
digitalWrite(in2, HIGH);
// Set Motor B backward
digitalWrite(in3, LOW);
digitalWrite(in4, HIGH);
// 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(yAxis, 470, 0, 0, 255);
motorSpeedB = map(yAxis, 470, 0, 0, 255);
}
else if (yAxis > 550) {
// Set Motor A forward
digitalWrite(in1, HIGH);
digitalWrite(in2, LOW);
// Set Motor B forward
digitalWrite(in3, HIGH);
digitalWrite(in4, LOW);
// 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(yAxis, 550, 1023, 0, 255);
motorSpeedB = map(yAxis, 550, 1023, 0, 255);
}
// If joystick stays in middle the motors are not moving
else {
motorSpeedA = 0;
motorSpeedB = 0;
}
// X-axis used for left and right control
if (xAxis < 470) {
// Convert the declining X-axis readings from 470 to 0 into increasing 0 to 255 value
int xMapped = map(xAxis, 470, 0, 0, 255);
// Move to left - decrease left motor speed, increase right motor speed
motorSpeedA = motorSpeedA - xMapped;
motorSpeedB = motorSpeedB + xMapped;
// Confine the range from 0 to 255
if (motorSpeedA < 0) {
motorSpeedA = 0;
}
if (motorSpeedB > 255) {
motorSpeedB = 255;
}
}
if (xAxis > 550) {
// Convert the increasing X-axis readings from 550 to 1023 into 0 to 255 value
int xMapped = map(xAxis, 550, 1023, 0, 255);
// Move right - decrease right motor speed, increase left motor speed
motorSpeedA = motorSpeedA + xMapped;
motorSpeedB = motorSpeedB - xMapped;
// Confine the range from 0 to 255
if (motorSpeedA > 255) {
motorSpeedA = 255;
}
if (motorSpeedB < 0) {
motorSpeedB = 0;
}
}
// Prevent buzzing at low speeds (Adjust according to your motors. My motors couldn't start moving if PWM value was below value of 70)
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
}

2

You have two if capturing the left turn or right turn

Just change the formula to get one motor in one direction and the other in the reverse direction at the value you want. Remember though that if your motor was spinning full speed ahead - say you were moving straight - then trying to get that motor to spin full speed the other way won’t be instantaneous and will put pressure on your equipment (Like if you were to try (don’t!!) running fast with your car and engage the reverse suddenly)

——

Please correct your post above and add code tags around your code:
[code]`` [color=blue]// your code is here[/color] ``[/code].

It should look like this:// your code is here
(Also press ctrl-T (PC) or cmd-T (Mac) in the IDE before copying to indent your code properly)

3

I see, would it be better to have 2 joysticks? One for each motor just forward and reverse, where I can control the speed independently?

4

mlaplas:
I see, would it be better to have 2 joysticks? One for each motor just forward and reverse, where I can control the speed independently?

That would probably be the easiest way to go. Like bulldozers and similar tracked equipment. For a single joystick you will have to think out the control logic. Two pots with sticks hot glued to the pot shafts could be the joysticks.

5

The only thing I can't figure is how to distinguish one joystick from the other on the master code.

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);
}

6

NVM problem solved! Thank you guys for the help. I used a second joystick one for each motor just forward and reverse. I used one stick for the y axis and the other on x axis just turned the stick 90 degrees to make it an up and down motion.

7

You already had two joysticks...

The Y axis could be the speed whilst the X axis could be the direction

That was already in your initial code