超音波距離センサ HC-SR04をArduinoで使う方法!超簡単に距離測定が可能

/** HC-SR04 Demo Demonstration of the HC-SR04 Ultrasonic Sensor Date: August 3, 2016 Description: Connect the ultrasonic sensor to the Arduino as per the hardware connections below. Run the sketch and open a serial monitor. The distance read from the sensor will be displayed in centimeters and inches. Hardware Connections: Arduino | HC-SR04 ------------------- 5V | VCC 7 | Trig 8 | Echo GND | GND License: Public Domain
*/
// Pins
const int TRIG_PIN = 7;
const int ECHO_PIN = 8;
// Anything over 400 cm (23200 us pulse) is "out of range"
const unsigned int MAX_DIST = 23200;
void setup() { // The Trigger pin will tell the sensor to range find pinMode(TRIG_PIN, OUTPUT); digitalWrite(TRIG_PIN, LOW); //Set Echo pin as input to measure the duration of //pulses coming back from the distance sensor pinMode(ECHO_PIN, INPUT); // We'll use the serial monitor to view the sensor output Serial.begin(9600);
}
void loop() { unsigned long t1; unsigned long t2; unsigned long pulse_width; float cm; float inches; // Hold the trigger pin high for at least 10 us digitalWrite(TRIG_PIN, HIGH); delayMicroseconds(10); digitalWrite(TRIG_PIN, LOW); // Wait for pulse on echo pin while ( digitalRead(ECHO_PIN) == 0 ); // Measure how long the echo pin was held high (pulse width) // Note: the micros() counter will overflow after ~70 min t1 = micros(); while ( digitalRead(ECHO_PIN) == 1); t2 = micros(); pulse_width = t2 - t1; // Calculate distance in centimeters and inches. The constants // are found in the datasheet, and calculated from the assumed speed //of sound in air at sea level (~340 m/s). cm = pulse_width / 58.0; inches = pulse_width / 148.0; // Print out results if ( pulse_width > MAX_DIST ) { Serial.println("Out of range"); } else { Serial.print(cm); Serial.print(" cm \t"); Serial.print(inches); Serial.println(" in"); } // Wait at least 60ms before next measurement delay(60);
}