Proximity sensor car – Learning path project 5

Our Learning Path is an itinerary designed to teach all the foundaments and a little more about electronics, coding and robotics.

When you complete all the projects you will be able to develop almost any project you can imagine. In each chapter new concepts are introduced. You will learn by doing in a funny way.

Discover the proximity sensor module, how to include it in your programs,  an build an autonomous car

Project 5
CAR PROXIMITY SENSOR

Avoid collisions and be one step closer to the autonomous vehicle with this amazing proximity sensor!

BEFORE TO START

DIFFICULTY LEVEL: Beginner
DURATION OF THE ACTIVITY: 45 min.

MATERIALS:
4in1 board
Potentiometer
Buzzer
Battery holder & wires
Battery holder & wires

1 - Build&Code 4in1 board
1 - Ultrasound module
1 - Buzzer
1 - Monochromatic Led light board

Battery holder, USB cable and wires.

5 - Car proximity sensor - Components

An ultrasonic sensor is a device to measure the distance. It functions by sending a high frequency sound pulse, not audible to the human ear. This pulse bounces on near objects and it’s reflected towards the sensor, that has a microphone suitable for this frequency.

By measuring the time between pulses and knowing the speed of the sound, we can estimate the distance of the object, on whose surface has bounced the sound pulse.

Ultrasonic sensor uses a digital input and a digital output. We send a pulse signal through output pin, and read pulse echo in input pin. For this reason this sensor needs 4 wires, Vcc and GND to power it, input and output.

Ultrasonic sounds are used in various applications to measure distances, tanks levels for example, or avoid collisions as a proximity sensor. Even bats use this technology!

5. How it works - Circuit

For first exercise you just need to connect the ultrasonic sensor but you can be ready for next exercises. Find here the circuit with all connected.

Connect wires from 4in1 board to components:
- DIO5 to Buzzer module
- DIO12 G pin to Gnd ultrasonic sensor pin
- DIO12 V pin to Vcc ultrasonic sensor pin
- DIO12 D pin to echo ultrasonic sensor pin
- DIO13 D pin to trig ultrasonic sensor pin

5.1 How it works - Program

We will create a function to measure distance. This function will send a pulse for some microseconds, and for response. We use function pulseIn , it measures the time that takes to the input pin to change from low to high state, and then we can calculate distance knowing speed of sound. This is repeated continuosly, and you can see output in serial monitor also (Arduino IDE)

Block Coding

This function not works with mBlock5 live mode, you will need to program in upload mode and see output with arduino IDE serial monitor.

Arduino Coding
int Trigger = 13;       // Para el Trigger del sensor declaramos el pin digital 13 
int Echo = 12;         // Para el Echo del sensor declaramos el pin digital 12 

float distance;         // distance medidad en centímetros
float vsound=34000.0;  // velocidad del sonido = 340m/s, la pasamos a cm 

// Para calcular la distance entre el sensor de ultrasonidos y el objeto partiremos de la fórmula: 
// distance recorrida= time * velocidad  --> distance recorrida= 2 veces la distance hacia el objeto --> 
// distance*2 = time * velocidad --> distance = (time * velocidad )/ 2


void setup() {
  Serial.begin(9600);             // Inicializamos la conexión serial
  pinMode(Trigger,OUTPUT);        //Declaramos el Trigger como salida
  pinMode(Echo,INPUT);            // Declaramos el Echo como entrada
  digitalWrite(Trigger, LOW);     //Inicializamos el pin con 0

}

void loop() {
  
  digitalWrite(Trigger,HIGH);     //Ponemos el Trigger en alto y esperamos 10 us
  delayMicroseconds(10);
  digitalWrite(Trigger,LOW);      // Volvemos a poner el Trigger en estado bajo

  unsigned long time= pulseIn(Echo,HIGH);   // Obtenemos el ancho del pulso
  distance=(time*0.000001*vsound)/2.0;    //como el time está en us, lo multiplicamos por 0.000001 para pasarlo a segundos
  Serial.println(distance);                  //Mostramos el valor de distance por el monitor serie y esperamos 1s.
  delay(500);
}
5.2 Parking sensor

A common application of current cars, to warn us when we are close to touching with some obstacle while parking in reverse gear. Let's go to create our own!

Block coding
Arduino code
int Buzzer=5;           // Declaramos el pin 5 para el Buzzer
int Trigger = 13;       // Para el Trigger del sensor declaramos el pin digital 2 
int Echo = 12;          // Para el Echo del sensor declaramos el pin digital 2 

float distance;          // distance medidad en centímetros
float vsonido=34000.0;   // velocidad del sonido = 340m/s, la pasamos a cm 

// Partiremos de la fórmula: distance recorrida= time * velocidad  --> distance recorrida= 2 veces la distance 
// hacia el objeto --> distance*2 = time * velocidad --> distance = (time * velocidad )/ 2


void setup() {
  //Serial.begin(9600);           // Inicializamos la conexión serial
  pinMode(Trigger,OUTPUT);        //Declaramos el Trigger como salida
  pinMode(Echo,INPUT);            // Declaramos el Echo como entrada
  digitalWrite(Trigger, LOW);     //Inicializamos el pin con 0

}

void loop() {
  
  digitalWrite(Trigger,HIGH);     //Ponemos el Trigger en alto y esperamos 10 us
  delayMicroseconds(10);
  digitalWrite(Trigger,LOW);      // Volvemos a poner el Trigger en estado bajo

  unsigned long time= pulseIn(Echo,HIGH);   // Obtenemos el ancho del pulso
  distance=(time*0.000001*vsonido)/2.0;     //Como el tiempo está en micorsegundos (us), lo multiplicamos por 0.000001 
                                            //para pasarlo a segundos
  
  
  if (distance <=30 && distance >20){
    tone(Buzzer,800,100);
    delay(1000);
  }
  
  if (distance <=20 && distance >10){
    tone(Buzzer,800,100);
    delay(500);
  }
  
  if (distance <=10 ){
    tone(Buzzer,800,100);
    delay(100);
  }
}

We used a buzzer that sounds more fast bips when closer, as real car ones. You can add some leds to has also a visual reference. Try to power on green, yellow and red LEDs when object is closer.

Final project - Car proximity sensor

Congratulations! You are ready to build our carton car and keep it safe when parking! Peease, print our cardboard templates and try code below. Note we introduced a function to get a nice code. Remember you can add and try anything your mind can imagine

Block coding
Arduino code
float ultrasonidos = 0;

float distancia(int trig,int echo){
    pinMode(trig,OUTPUT);
    digitalWrite(trig,LOW);
    delayMicroseconds(2);
    digitalWrite(trig,HIGH);
    delayMicroseconds(10);
    digitalWrite(trig,LOW);
    pinMode(echo, INPUT);
    return pulseIn(echo,HIGH,30000)/58.0;
}

void sonidoProximidad(double tiempo){
  tone(9,65,100);
  delay(float(tiempo));
  tone(9,65,100);
  delay(float(tiempo));

}

void setup() {
  pinMode(9,INPUT);

}

void loop() {
  ultrasonidos = distancia(13,12);
  if(ultrasonidos < 10){
      tone(9,65,100);
  }
  if((ultrasonidos > 5)  &&  (ultrasonidos < 10)){
      sonidoProximidad(200);
  }
  if((ultrasonidos > 10)  &&  (ultrasonidos < 15)){
      sonidoProximidad(300);
  }
  if((ultrasonidos > 15)  &&  (ultrasonidos < 20)){
      sonidoProximidad(400);
  }
  if((ultrasonidos > 20)  &&  (ultrasonidos < 25)){
      sonidoProximidad(500);
  }
  if((ultrasonidos > 25)  &&  (ultrasonidos < 30)){
      sonidoProximidad(600);
  }
  if((ultrasonidos > 30)  &&  (ultrasonidos < 35)){
      sonidoProximidad(700);
  }
  if((ultrasonidos > 35)  &&  (ultrasonidos < 40)){
      sonidoProximidad(800);
  }
  if((ultrasonidos > 40)  &&  (ultrasonidos < 45)){
      sonidoProximidad(900);
  }
  if((ultrasonidos > 45)  &&  (ultrasonidos < 50)){
      sonidoProximidad(100);
  }
}
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The Mega Maker Kit fits perfectly with the Learning Path, you can build all projects with it, but if you have other kits, you can also follow the entire itinerary and finish some projects, or buy the missing components. You can check in our Learning Path page.

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