Understanding the code of the project

Projects Programming
1

Hi,
I want to create this project - https://www.instructables.com/Motion-Tracking-Face/
But I want to understand that how does the ultrasoinc sensor turns according to the moving object/person, i.e how does it track and the servos turn accordingly. Is the ultrasonic sensor sending data of the moving object or is there any other sensor or something. The wiring given by the creator is confusing because he hasn't mentioned all the used parts and proper list of it. I am excluding the eye part and LED part...

HERE'S THE CODE -

// SERVO 
#include <Servo.h>

//NEOPIXELS
#include <Adafruit_NeoPixel.h>

//STEPPER
#include "Stepper_28BYJ_48.h"

#ifdef __AVR__
  #include <avr/power.h>
#endif

//set out signal pin
#define PIN 9

Adafruit_NeoPixel strip = Adafruit_NeoPixel(2, PIN, NEO_GRB + NEO_KHZ800);

const int echo = 2;
const int trig = 3;
const int ultrasonicServoPin = 5; 
const int ledStatusPin = 7;
const int eyeServoPin = 6;
const int ledPixelPin = 9;
Stepper_28BYJ_48 stepper(10,11,12,13);

Servo ultServo;
Servo eyeServo;

int ultAngle = 90;
int eyeAngle = 90;
int stepperAngle = 90;

long dur;
int dist;

long lastSeen;

void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT); 
  pinMode(ledStatusPin, OUTPUT);
  
  ultServo.attach(ultrasonicServoPin); //48deg -> 120
  eyeServo.attach(eyeServoPin); //0 -> 180
  ultServo.write(90);
  eyeServo.write(90);
  
  strip.begin();
  strip.show();
  
  Serial.begin(9600); // Starts the serial communication
}

void loop() {
  /*
  REMOTE CONTROL
  int tester = analogRead(0);
  int mapper = map(tester,0,1023,0,3);
  setEyes(mapper);
  
  if(digitalRead(1) == LOW){
    stepper.step(1);
  }
  if(digitalRead(2) == LOW){
    stepper.step(-1);
  }
  */
  
  //MOVE SCANNER -> MOVE STEPPER -> MOVE EYES
  
  int lastAngle = ultAngle;
  
  // //ULTRASONIC TRACKING
  getDistance();
  //Serial.println(dist);
  if (dist > 10 && dist < 30){ //30 for testing
    //Serial.println("Distance: " + String(dist) + " Angle: " + String(ultAngle));
    digitalWrite(ledStatusPin, HIGH);
    if (ultAngle < 60){
      ultAngle = 60;
    }else{
      ultAngle-=6;
    }
  }else{
    digitalWrite(ledStatusPin, LOW);
    if (ultAngle > 120){
      ultAngle = 120;
    }else{
      ultAngle++;
    }
  }
  if (ultAngle > 50 && ultAngle < 108){
    lastSeen = millis();
  }
  if (lastAngle != ultAngle){
    ultServo.write(ultAngle);
  }
  Serial.println(ultAngle);

  delay(1);
  
  
  //STEPPER ------------------------------------------
  stepToDeg(ultAngle);
  delay(1);
  
  //EYES ---------------------------------------------
  long lastContact = (millis()-lastSeen);
  //Serial.println(lastContact);
  if (lastContact > 3000 && lastContact < 6000){
    setEyes(2);
  }else if (lastContact <= 3000){
    setEyes(1);
  }else{
    setEyes(0);
  }
}

// -----------------------------------------------------------------------------------------

void stepToDeg(int stepAngle){
  if (ultAngle < 121){
    int difference = stepperAngle - ultAngle;
    int absDifference = abs(difference);
    int negDif = -difference*7;
    stepper.step(negDif);
    stepperAngle = ultAngle;
  }
}

void getDistance(){ //TAKES AN ULTRASONIC MEASUREMENT AND RETURNS THE COMPUTED DISTANCE IN CM
  // Clears the trigPin
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  
  //Sends pulse
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  dur = pulseIn(echo, HIGH);
    
  dist = dur*0.034/2;
}

void setEyes(int mode){ //SETS THE ANGLE OF THE EYE SERVO FOR VARIOUS EXPRESSIONS
  switch (mode) { //DEFAULT:NEUTRAL 1:HAPPY 2:SAD
    case 1: //HAPPY
      eyeServo.write(179);
      for(uint16_t i=0; i<strip.numPixels(); i++){
        strip.setPixelColor(i,255,140,0);
        strip.show();
      }
      break;
    case 2: //SAD
      eyeServo.write(1);
      for(uint16_t i=0; i<strip.numPixels(); i++){
        strip.setPixelColor(i,90,90,255);
        strip.show();
      }
      break;
    default: //NEUTRAL
      eyeServo.write(99);
      for(uint16_t i=0; i<strip.numPixels(); i++){
        strip.setPixelColor(i,255,200,180);
        strip.show();
      }
      break;
  }
}

Also, I have a doubt... When he includes the stepper library, he has used quotation marks instead of the arrow marks.. will it still be included?

Thanking you in advance

1 Like
2

To understand someone else's program usually takes a lot of work, and it is unlikely that someone on this forum will do that for you and then write a detailed explanation.

However, questions about the function of a few specific lines of code are welcome and often easy to answer.

#include directives with quote marks look in your local directories for files, whereas those with angle brackets look in Arduino IDE program directories.

BTW many, if not most Instructables are written by people who have little to no idea what they are doing, and can be wrong or unsafe, poorly written and confusing. Look elsewhere for similar projects and you may find much better candidates for study.

2 Likes
3

Better still write your own code !

2 Likes
4

that's what I fail everytime in :sweat_smile:

5

Get practising … using code you find is ultimately frustrating , you can’t modify or fix it or learn anything .
Do some simple stuff , enjoy it and learn something , then get better at it

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6

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