Light and sound responsive line following robot

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• In this project, I learned all the various ways to interface various sensors to measure and sense real world data and manipulate them acordingly.
• Understanding the fundamentals for engineering electronic interfaces between the physical world and digital devices and their corresponding data.
• Developing an understanding of the building blocks of electronics.
• Analyze, design, and build different parts of a robot from scratch.

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Block Diagram

Flow Chart

Various Module and their Parts

1. Module 1. Power Supply

• Voltage Regulator
• 10 μf capacitors

Yes, thats a homemade power supply :)

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2. Module 2. Light Sensor

• Photocells + Comparators
• 2.7 KΩ resistors
• LM358
• LEDs
• 300 Ω current-limiting resistors

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3. Module 3. Buzzer Driver

• LM358
• speaker

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4. Module 4. Microphone Amplifier

• Electret mic
• 10 kOhm resistors
• 2.7 kΩ resistor
• 100 kΩ resistor
• 1 μF cap
• LM358

5. Module 5. Motor Drivers

• DC motors
• IN4001 diodes
• steel nuts
• PN2222 NPN transistors
• 1 kΩ resistors

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Final Code:

#  _________                                         ___ ___          .__       .___                
# /   _____/_____    __ __ _______ _____   ___  __  /   |   \ _____   |  |    __| _/_____   _______ 
# \_____  \ \__  \  |  |  \\_  __ \\__  \  \  \/ / /    ~    \\__  \  |  |   / __ | \__  \  \_  __ \
# /        \ / __ \_|  |  / |  | \/ / __ \_ \   /  \    Y    / / __ \_|  |__/ /_/ |  / __ \_ |  | \/
#/_______  /(____  /|____/  |__|   (____  /  \_/    \___|_  / (____  /|____/\____ | (____  / |__|   
#       \/      \/                     \/                \/       \/            \/      \/         

# Start Of Program---------------------------------------------------------------------------------------------------------

//***************************************************************************************
//  Description; Final code that runs the robot
//  Saurav Haldar
//  March  23, 2015
//***************************************************************************************

int PBLOCK = 11;  // set PBLOCK as P1.1 alias
int BUZZER = 2;   // set BUZZER as P1.3 alias
int LMOTOR = 3;   // set LMOTOR as P2.1 alias
int RMOTOR = 5;   // set RMOTOR as P1.6 alias
int LPHOTO = 8;  // set LPHOTO as P1.2 alias
int RPHOTO = 13;  // set RPHOTO as P1.7 alias
int MICINP = A0;  // set MICINP as A5   alias
int LED3   = 4;   // MicroPhone led 

int MPOW   = 230;   // set motors to use 50% PWM (possible values 0-255)
int MICTHRESH = 20; // set microphone trigger threshold (possible values 0-1023)

int i;
int val;
int maxval;

void setup()
{  

  // set outputs
  pinMode(LMOTOR, OUTPUT);
  pinMode(RMOTOR, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(PBLOCK, OUTPUT);

  // set inputs
  pinMode(LPHOTO, INPUT);
  pinMode(RPHOTO, INPUT);

}

void loop()
{
  analogWrite(LMOTOR,0);        // turn off both motors 
  analogWrite(RMOTOR,0);

  // Step 1: beep a bunch of times!
  for (i=1; i<5; i++)
  {
    beep(BUZZER, 1000, 100*i);
    delay(100*i);
  }

  // Step 2: listen to the microphone for ~100 ms
  maxval = 0;
  for (i=1; i<100; i++)
  {
    val = analogRead(MICINP);
    if (val >= 20)            // if digitized value is above 560,
    digitalWrite(LED3, HIGH); // turn on the LED...
    else
    digitalWrite(LED3, LOW); 
    if (val > maxval)
      maxval = val;
    delay(1);
  }

  // If the largest voltage detected is above 1.94 V (3.3*600/1023),
  // commence the "beep dance" response
  if (maxval > MICTHRESH)
  {
    // Make the "siren" noise by alternating 1200 Hz and 800 Hz tones
    for (i=0; i<5; i++)
    {
        beep(BUZZER, 1200, 100);
        beep(BUZZER, 800,  100);
    }
    // Shake motors back and forth rapidly
    for (i=0; i<3; i++)
    {
        analogWrite(RMOTOR, MPOW);
        delay(200);
        analogWrite(RMOTOR, 0);
        analogWrite(LMOTOR, MPOW);
        delay(200);
        analogWrite(LMOTOR, 0);
    }
    // Make a series of tones with increasing frequency from 300-100 Hz
    // then come back down
    for (i=30; i<100; i+=1)
      beep(BUZZER, 10*i, 10);
    for (i=100; i>30; i-=1)
      beep(BUZZER, 10*i, 10);
  } 
  // Step 3: read the status of photocells and adjust motor output
  digitalWrite(PBLOCK, HIGH);      // supply 3.3V to the power rail
  delayMicroseconds(20);           // delay briefly to allow comparator outputs to settle

  if (digitalRead(LPHOTO)==HIGH)         // check each photocell/circuit output and determine
      analogWrite(LMOTOR, MPOW);

  if (digitalRead(RPHOTO)==HIGH)  
       analogWrite(RMOTOR, MPOW);


    digitalWrite(PBLOCK, LOW);       // turn the power-blocked rail off
    delay(500);                      // wait 500 ms

 }

void beep(int pin, int freq, long ms)    //generate a square wave at a given frequency for ms miliseconds
{
  int k;
        long semiper = (long) (1000000/(freq*2));
        long loops = (long)((ms*1000)/(semiper*2));
  for (k=0;k<loops;k++)
  {
            digitalWrite(pin, HIGH);  //set buzzer pin high
      delayMicroseconds(semiper);  //for half of the period
      digitalWrite(pin, LOW);   //set buzzer pin low
            delayMicroseconds(semiper);  //for the other half of the period
  }
}

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