A 4WD remote controlled car part II

The car was going; forwards, backwards and at two speeds. The code was an extension of a tutorial and needed to be rewritten for easier development.
The next step was experimenting with turns, and using LEDs for 2 x reverse lights, 2 x brake lights, and 4 x indicators.

The turns were hugely successful; stopping the wheels on one side made it spin on a sixpence. The code is below.

Shift register

The other thing required was to use a shift register, to reduce the # of arduino pins. The speed controls had to use the PWM pins, but the L293D inputs could be put to the shift register. Here is the code post-tutorial.

/*
 4WD Car chassis.
 Paul Goodliffe, May 2014
 */
 
 
//L293 Pin assignments

const int FULL       = 255;
const int SLOW       = 0;

//Motor one
int m1_enable        = 3;  // Must be PWM for speed control
int m1_forward       = 2;  
int m1_backward      = 4;   

//Motor two
int m2_enable        = 5;  // Must be PWM for speed control
int m2_forward       = 7;   
int m2_backward      = 6;  
//Motor 3
int m3_enable        = 10;  // Must be PWM for speed control
int m3_forward       = 8;
int m3_backward      = 9;

//Motor 4
int m4_enable        = 13;      // Must be PWM for speed control
int m4_forward       = 12;
int m4_backward      = 11;


void setup(){
  pinMode(m1_enable, OUTPUT);  //Set the three pins for bridge 1 & 2 to outputs
  pinMode(m1_forward, OUTPUT);
  pinMode(m1_backward, OUTPUT);

  pinMode(m2_enable, OUTPUT);  //Set the three pins for 3 & 4 to outputs
  pinMode(m2_forward, OUTPUT);
  pinMode(m2_backward, OUTPUT); 
  
  pinMode(m3_enable, OUTPUT);  //Set the three pins for bridge 1 & 2 to outputs
  pinMode(m3_forward, OUTPUT);
  pinMode(m3_backward, OUTPUT);

  pinMode(m4_enable, OUTPUT);  //Set the three pins for 3 & 4 to outputs
  pinMode(m4_forward, OUTPUT);
  pinMode(m4_backward, OUTPUT);  
}

void loop()
{
  setMyspeed(FULL);
  goForwards();
  delay(1000);
  goBackwards();
  delay(1000);
  
  turnLeft();  // WOW ! Turns on a ninepence !!
  goForwards();
  delay(1000); // 1 second of max turn is about 180 deg :-) )

  turnRight();
  goBackwards();
  delay(1000);

  turnLeft();
  goForwards();
  delay(1000);

}

void turnLeft()
{
brakeAll();
setLeftSpeed(SLOW);
setRightSpeed(FULL);
}
void turnRight()
{
brakeAll();
setLeftSpeed(FULL);
setRightSpeed(SLOW);
}

void setLeftSpeed(int newSpeed)
{ // Motors : Front is 2 and 1. Rear is 3 and 4. Left is 2 and 3. Right is 1 and 4.
  analogWrite(m2_enable, newSpeed);
  analogWrite(m3_enable, newSpeed);
}
void setRightSpeed(int newSpeed)
{ // Motors : Front is 2 and 1. Rear is 3 and 4. Left is 2 and 3. Right is 1 and 4.
  analogWrite(m1_enable, newSpeed);
  analogWrite(m4_enable, newSpeed);
}


////// Motor One Routines  ////////////
void goForwards()
{
  brakeAll();
 digitalWrite(m1_forward, LOW); 
 digitalWrite(m1_backward, HIGH); 
 digitalWrite(m2_forward, LOW); 
 digitalWrite(m2_backward, HIGH); 
 digitalWrite(m3_forward, LOW); 
 digitalWrite(m3_backward, HIGH); 
 digitalWrite(m4_forward, LOW); 
 digitalWrite(m4_backward, HIGH); 
}

void goBackwards()
{
  brakeAll();
 digitalWrite(m1_forward, HIGH); 
 digitalWrite(m1_backward, LOW); 
 digitalWrite(m2_forward, HIGH); 
 digitalWrite(m2_backward, LOW); 
 digitalWrite(m3_forward, HIGH); 
 digitalWrite(m3_backward, LOW); 
 digitalWrite(m4_forward, HIGH); 
 digitalWrite(m4_backward, LOW); 
}   

void setMyspeed(int newSpeed)
{
  analogWrite(m1_enable, newSpeed);
  analogWrite(m2_enable, newSpeed);
  analogWrite(m3_enable, newSpeed);
  analogWrite(m4_enable, newSpeed);
}

void brakeAll()
{
 digitalWrite(m1_forward, LOW); 
 digitalWrite(m1_backward, LOW); 
 digitalWrite(m2_forward, LOW); 
 digitalWrite(m2_backward, LOW); 
 digitalWrite(m3_forward, LOW); 
 digitalWrite(m3_backward, LOW); 
 digitalWrite(m4_forward, LOW); 
 digitalWrite(m4_backward, LOW); 
 delay(500); // Give the motors time to react
}

My 4WD car chassis kit.
The chassis has the protecting layer on at the mo.
4 motors, one already fixed in. 4 wheels.

There's also another 'wheel' to attach inside the chassis, that you can just see. I think it can be used for measuring distance. More on that later.

The Start

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A 4WD remote controlled car part II

Shift register