====== LamaPLC: HC-SR04 Ultrasonic Sensor Module ======
{{ :sensor:hc_sr04.png?250|HC SR04}}
**Ultra-Sonic Ranger sensors** \\ 
This solution has two components: a speaker that sends out sound pulses and a microphone that detects their reflections. The distance is computed from the time delay between emission and detection, assuming the speed of sound.

**HC-SR04** \\
The HC-SR04 ultrasonic sensor module is a widely used, affordable sensor popular among hobbyists for electronics projects with Arduino and Raspberry Pi, enabling non-contact distance measurement and obstacle detection. It uses sonar to measure distance by timing how long sound waves take to reflect back.
===== Key Specifications ===== 
  * **Operating Voltage:** **5V DC**
  * **Operating Current:** 15mA
  * **Ranging Distance:** 2cm to 400cm (4m)
  * **Accuracy:** Up to 0.3cm, though some real-world tests suggest around 1cm
  * **Measuring Angle:** Less than 15 degrees in a cone
  * **Ultrasonic Frequency:** 40kHz
  * **Dimensions:** Approximately 45mm x 20mm x 15mm

{{page>:tarhal}}

==== Arduino & HC-SR04 ====
  * **VCC:** Power supply (5V DC)
  * **Trig (Trigger):** Input pin to trigger the ultrasonic burst
  * **Echo:** Output pin that produces a pulse proportional to the time taken for the echo to return
  * **GND:** Ground
  
To operate the sensor, a microcontroller (like an Arduino) must provide a 10-microsecond (µS) high-level pulse to the Trig pin. The module then automatically sends out an 8-cycle burst of ultrasound at 40 kHz and raises the Echo pin to a high state. The duration of this high-level signal on the Echo pin is the time the sound waves took to travel to the object and back.

The distance can be calculated using the formula: \\
Distance in cm = (Duration of Echo pulse in µS / 58)

<code c>
const int trigPin = 9;
const int echoPin = 10;

float duration, distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = (duration*.0343)/2;
  Serial.print("Distance: ");
  Serial.println(distance);
  delay(100);
}
</code>

{{tag>HC-SR04 Ultrasonic sensor arduino code}}

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