mattnett: Arduino - Reverse Car Parking Alarm

As promised in the previous post, we will be building a Reverse Parking alarm for cars. For doing so we will utilize the same wiring scheme as in my previous post. However, we will change the C sketch slightly. The change in the C code will be to start beeping the Piezo Buzzer at longer intervals when the Car is 30 centimeters (1 feet) away from an object, followed by intensifying the beeping at shorter intervals as the Car comes closer to the obstacle. Watch the Youtube video of the sample project below.

Setup the wiring for the reverse parking alarm as described in my previous post. Followed by using the C program written below.

int trigPin = 4;
int echoPin = 12;
int buzzerPin = 8;
int interval_30cm = 500;
int interval_20cm = 250;
int interval_10cm = 150;
int freq_30cm = 25re0;
int freq_20cm = 450;
int freq_10cm = 550;

void setup()
{
  // initialize the pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
}

void loop()
{
  long duration, distance;

// Signal a quick LOW just before giving a HIGH signal
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

// After 2 milli-seconds of LOW signal, give a HIGH signal to trigger the sensor
  digitalWrite(trigPin, HIGH);
  // Keep the digital signal HIGH for
  // at least 10 milli-seconds (required by HC-SR04 to activate emission of
  // ultra sonic waves
  delayMicroseconds(10);

// After 10 milli-seconds, signal a LOW
  digitalWrite(trigPin, LOW);

// Now wait for the Ultra sonic echo to return from an obstacle
  duration = pulseIn(echoPin, HIGH);

// Convert the distance to centimeters
  distance = (duration/2) / 29.1;

if (distance > 20 && distance <= 30)
  {
    buzz(freq_30cm);
    delay(interval_30cm);
  }
  else if (distance > 10 && distance <= 20)
  {
    buzz(freq_20cm);
    delay(interval_20cm);
  }
  else if (distance <= 10)
  {
    buzz(freq_10cm);
    delay(interval_10cm);
  }
}

void buzz(int freq)
{
  tone(buzzerPin, freq, 100);
}

Hope you enjoyed this article! Please share and comment on this post if you found it useful. I would love to hear from you.

Cheers,
KBRC

Arduino - Reverse Car Parking Alarm

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