trouble with HC-SR04 and 5V DC motor

Projects Programming
1

So, my son has a project for school and I'm helping him because it's very hard. i said that i would do the coding but, i'm jsut don't really know how this arduine works, i took classes and tried but i can't understand it. the thing that are being used are the HC-SR04 infrared sensor and a normal, small 5V DC motor. When the Infrared sensor sees something within 30cm of it than the Dc motor should go backwards but i can't seem to find a code for this, can anyone help me?

2

Post your code, please.

Perhaps if you understand that it's an ultrasound ranger, not IR, things might be a little clearer.

3

this is my code at the moment

const int trigPin = 2;
const int echoPin = 4;
int motorPin = 3;

void setup() {
// initialize serial communication:
Serial.begin(9600);
}

void loop()
{

long duration, inches, cm;

pinMode(trigPin, OUTPUT);
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

pinMode(echoPin, INPUT);
duration = pulseIn(echoPin, HIGH);

inches = microsecondsToInches(duration);
cm = microsecondsToCentimeters(duration);

Serial.print(inches);
Serial.print("in, ");
Serial.print(cm);
Serial.print("cm");
Serial.println();

delay(100);
if (Serial.print > 20cm) {
digitalWrite(pinMode, HIGH);
} else {
digitalWrite(pinMode, LOW);
}
}

long microsecondsToInches(long microseconds)
{
return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{

return microseconds / 29 / 2;
}

4

That code doesn't compile, and there is nothing in that code that hints at motor control.

There are many worked examples for this device.

5

you're saying the code is totally wrong? Where can i find a good code?

6

No, the compiler already told you the code was wrong.

I'm just confirming it.
Where did you find that code?

7

(deleted)

8

Work out how to read the distance (The example code you posted does this)

No, it doesn't - read it.

9

Back at a computer now.

Try this - I haven't compiled it.

const byte trigPin = 2;
const byte echoPin = 4;
const byte motorPin = 3;

void setup() {
  // initialize serial communication:
  Serial.begin(9600);
  pinMode (trigPin, OUTPUT);
  digitalWrite(trigPin, LOW);
  pinMode (echoPin, INPUT);
  pinMode (motorPin, OUTPUT);
}

void loop()
{
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
 
  unsigned long duration = pulseIn(echoPin, HIGH);
  unsigned long  inches = microsecondsToInches(duration);
  unsigned cm = microsecondsToCentimeters(duration);
 
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.println("cm");
 
  delay(100);
  if (cm > 20) {
     digitalWrite(motorPin, HIGH);
  } else {
    digitalWrite(motorPin, LOW);
  }
}

unsigned long microsecondsToInches(unsigned long microseconds)
{
  return microseconds / 74 / 2;
}

unsigned long microsecondsToCentimeters(unsigned long microseconds)
{
   return microseconds / 29 / 2;
}