Lie Detector

With this machine you will know if somebody is being sincere or not with you.

Step 1: Electronic Components

Arduino Genuino UNO x2

Protoboard

Cables

DC Motor

Transistor

Servo motor

Red LED

Green LED

Arduino pulsometer

Resistor x3

Potentiometer

Step 2: Connection

Here you can see the scheme of the connections.

Step 3: Code 1

// This code below serves to simulate a lie detector.

//It has been created by Nicolas Baqués and Carolina Romanos.

//First of all all the variables have to be declared.

//DC MOTOR
int motorPin = 9;           // the PWM pin the LED is attached to
int power = 100;

//SENSOR
int pulse=0; //Variable that will convert 

//SERVO
#include
Servo servoMotor; //Declare the servo

//LEDs

int ledPin1 = 6; // Green LED is connected to pin 6
int ledPin2 = 5; // Red LED is connected to pin 5

void setup() {
  // put your setup code here, to run once:
  
Serial.begin(9600); //Sets the data rate in bits per second or serial data transmission
  
   //DC MOTOR
  pinMode(motorPin, OUTPUT);
  

  //SENSOR
  pinMode(A5,INPUT);//Saying that we are collecting information from A0

  //SERVO
  servoMotor.attach(13);// Servo connected to pin 13

  //LEDs
  pinMode(ledPin1,OUTPUT); //Saying that the LED receives information
  pinMode(ledPin2,OUTPUT); //Saying that the LED receives information

}

void loop() {
  // put your main code here, to run repeatedly:

  //DC MOTOR
  analogWrite(motorPin, power);  //Telling the DC motor in Pin 9 the speed we want 64 (slow)
  delay (30);
  
  //SENSOR
  pulse= (analogRead(A0)); //Pulse will be what Arduino reads in A5
  Serial.println(pulse); //Print the reading in the monitor serie
  delay(1);

  //SERVO
  servoMotor.write(0); // Inicial position of the Servo is 0 degrees

  
  if (((600<(analogRead(A0))))){ //Condition for the servo
                                  //if the reading in A5 is more than 600
    
   for (int i=0; i<=30; i++){     //The servo will move continously 90 degrees in both directions
     servoMotor.write(i);
      delay(25);
   }
    for (int i=29; i>0; i--){
     servoMotor.write(i);
      delay(25);
    }
  }

  if (((600>(analogRead(A0))))){ //Condition for the servo if the reading in A5 is less than 600
    
    for ( int i = 0; i <= 15; i++){ //The servo will move continously 45 degrees in both directions
      servoMotor.write(i);
      delay(25);
    }
    for ( int i = 14; i>0; i--){
      servoMotor.write(i);
      delay(25);
    }
  }
  

//LEDs

 if (((600<(analogRead(A0))))){ 
  digitalWrite(ledPin2 , HIGH);   // Switch on the LED 2 when analog read is more than 600
  digitalWrite(ledPin1 , LOW);    // LED 1 stays off when analog read is more than 600
  delay (100);
 }
  if (((600>(analogRead(A0))))){
  
  digitalWrite(ledPin1, HIGH); //Switch on the LED 1 when analog read is less than 600
  digitalWrite(ledPin2 , LOW);  // LED 2 stays off when analog read is less than 600
  delay (100);

}
}
//IMPORTANT: to simulate a person is lying change the analog read of port A5 to A0!
//This would make possible to control the data the servo is reading with a potentiometer

Step 4: Code 2

int motorPin = 9;           // the PWM pin the DC Motor  is attached to

int power = 100;    // how fast the DC Motor is

// the setup routine runs once when you press reset:
void setup() {
  
  // declare pin 9 to be an output:
  pinMode(motorPin, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  
  // set the power of pin 9:
  analogWrite(motorPin, power);
 
}

Step 5: Structure

In this step I show the plan of the box. Using Autocad is the simplest way to draw it.

Step 6: Production

After making plans of the box, you must buy a 4mm wood and cut the different parts using a laser cut.

Step 7: Building

Join the different pieces of the box using glue. And for organizing the inside box part, you must buy polyurethane foam and used the best way you think is.

Step 8: Display

How the lie detector looks like.

Step 9: Problems & Improvements

The only problem that our lie detector has given us is transform the pulsations into BPM. Also say that the Arduino pulsometers aren't very professionals and does not always work perfectly.

We found that our lie detector could be improved by introducing another DC motor, making it pick up all the remaining paper, re-rolling it.

Step 10: Ready to Ask