Question

How do I change my if statements into while and for loops, so that I can make my bot go straight and turn exactly 12 times.

/***********************************************************************
* Exp7_1_RotaryEncoder -- RedBot Experiment 7_1
*
* Knowing where your robot is can be very important. The RedBot supports
* the use of an encoder to track the number of revolutions each wheels has
* made, so you can tell not only how far each wheel has traveled but how
* fast the wheels are turning.
*
* This sketch was written by SparkFun Electronics, with lots of help from
* the Arduino community. This code is completely free for any use.
*
* 8 Oct 2013 M. Hord
* Revised, 31 Oct 2014 B. Huang
***********************************************************************/

#include <RedBot.h>
RedBotMotors motors;

RedBotEncoder encoder = RedBotEncoder(3,9); // initializes encoder on pins A2 and 10
int buttonPin = 12;
int countsPerRev = 192; // 4 pairs of N-S x 48:1 gearbox = 192 ticks per wheel rev

// variables used to store the left and right encoder counts.
int lCount;
int rCount;

void setup()
{
pinMode(buttonPin, INPUT_PULLUP);
Serial.begin(9600);
Serial.println("left right");
Serial.println("================");
}

void turn()

{

long lCount = 0;

long rCount = 0;

long targetCount;

float numRev;

motors.leftMotor(-80);

motors.rightMotor(0);
// variables for tracking the left and right encoder counts

long prevlCount, prevrCount;

long lDiff, rDiff; // diff between current encoder count and previous count

encoder.clearEnc(BOTH); // clear the encoder count

delay(100); // short delay before starting the motors.

while (lCount < 0)

{

// while the right encoder is less than the target count – debug print

// the encoder values and wait – this is a holding loop.

lCount = encoder.getTicks(LEFT);

rCount = encoder.getTicks(RIGHT);

Serial.print(lCount);

Serial.print("\t");

Serial.print(rCount);

Serial.print("\t");

Serial.println(targetCount);

// calculate the rotation “speed” as a difference in the count from previous cycle.

lDiff = (lCount - prevlCount);

rDiff = (rCount - prevrCount);

// store the current count as the “previous” count for the next cycle.

prevlCount = lCount;

prevrCount = rCount;

}

delay(500); // short delay to give motors a chance to respond.
motors.brake();

}

void loop(void)
{
  
// wait for a button press to start driving.

  
if(digitalRead(buttonPin) == LOW)
{
encoder.clearEnc(BOTH); // Reset the counters.
delay(500);
motors.drive(180); // Start driving forward.
}
  

// store the encoder counts to a variable.
lCount = encoder.getTicks(LEFT); // read the left motor encoder
rCount = encoder.getTicks(RIGHT); // read the right motor encoder

// print out to Serial Monitor the left and right encoder counts.
Serial.print(lCount);
Serial.print("\t");
Serial.println(rCount);

// if either left or right motor are more than 5 revolutions, stop
  
if ((lCount >= 5*countsPerRev) || (rCount >= 5*countsPerRev ))
{
  
turn();
encoder.clearEnc(BOTH);
//motors.brake();
delay(500);
motors.drive(180); // Start driving forward.
  
  
}
  
}

Answer 1

Below is a sample code doing the same:

CODE

#include <RedBot.h>
RedBotMotors motors;

RedBotEncoder encoder = RedBotEncoder(3,9); // initializes encoder on pins A2 and 10
int buttonPin = 12;
int countsPerRev = 192; // 4 pairs of N-S x 48:1 gearbox = 192 ticks per wheel rev

// variables used to store the left and right encoder counts.
int lCount;
int rCount;

void setup()
{
pinMode(buttonPin, INPUT_PULLUP);
Serial.begin(9600);
Serial.println("left right");
Serial.println("================");
}

void turn()

{

long lCount = 0;

long rCount = 0;

long targetCount;

float numRev;

motors.leftMotor(-80);

motors.rightMotor(0);
// variables for tracking the left and right encoder counts

long prevlCount, prevrCount;

long lDiff, rDiff; // diff between current encoder count and previous count

encoder.clearEnc(BOTH); // clear the encoder count

delay(100); // short delay before starting the motors.

while (lCount < 0)

{

// while the right encoder is less than the target count – debug print

// the encoder values and wait – this is a holding loop.

lCount = encoder.getTicks(LEFT);

rCount = encoder.getTicks(RIGHT);

Serial.print(lCount);

Serial.print("\t");

Serial.print(rCount);

Serial.print("\t");

Serial.println(targetCount);

// calculate the rotation “speed” as a difference in the count from previous cycle.

lDiff = (lCount - prevlCount);

rDiff = (rCount - prevrCount);

// store the current count as the “previous” count for the next cycle.

prevlCount = lCount;

prevrCount = rCount;

}

delay(500); // short delay to give motors a chance to respond.
motors.brake();

}

void loop(void)
{
  
// wait for a button press to start driving.

  
if(digitalRead(buttonPin) == LOW)
{
encoder.clearEnc(BOTH); // Reset the counters.
delay(500);
motors.drive(180); // Start driving forward.
}
  

// store the encoder counts to a variable.
lCount = encoder.getTicks(LEFT); // read the left motor encoder
rCount = encoder.getTicks(RIGHT); // read the right motor encoder

// print out to Serial Monitor the left and right encoder counts.
Serial.print(lCount);
Serial.print("\t");
Serial.println(rCount);

// if either left or right motor are more than 5 revolutions, stop

int count = 0;
  
while (count < 12)
{

if (lCount >= 5*countsPerRev) || (rCount >= 5*countsPerRev )
{
turn();
encoder.clearEnc(BOTH);
//motors.brake();
delay(500);
motors.drive(180); // Start driving forward.

count ++;
}
  
}
  
}