40 lines
1.1 KiB
Arduino
40 lines
1.1 KiB
Arduino
|
#define US_TRIG 13
|
||
|
|
#define US_ECHO 12
|
||
|
|
|
||
|
|
long distance_cm, echo_duration;
|
||
|
|
|
||
|
|
void setup() {
|
||
|
|
//Serial port
|
||
|
|
Serial.begin(115200);
|
||
|
|
|
||
|
|
//Ultra sonic pins
|
||
|
|
pinMode(US_TRIG, OUTPUT);
|
||
|
|
pinMode(US_ECHO, INPUT);
|
||
|
|
}
|
||
|
|
|
||
|
|
void loop() {
|
||
|
|
// start measurment by a short high pulse of 10 microseconds length at the trig pin ...
|
||
|
|
digitalWrite(US_TRIG,LOW);
|
||
|
|
delayMicroseconds(2);
|
||
|
|
digitalWrite(US_TRIG,HIGH);
|
||
|
|
delayMicroseconds(10);
|
||
|
|
digitalWrite(US_TRIG,LOW);
|
||
|
|
|
||
|
|
// measure the duration in microseconds of the echo pin HIGH - this is the time the echo needs to be back at the sensor
|
||
|
|
pinMode(US_ECHO,INPUT);
|
||
|
|
echo_duration = pulseIn(US_ECHO,HIGH);
|
||
|
|
|
||
|
|
// convert into cm ... 344m/sec is the speed of noise - thus 34400cm/sec ... or 34,400cm/milisec ... or 0,0344cm/microsec
|
||
|
|
// the echo has to go the distance twice - forth and back - so the duration has to be the half of the measured one
|
||
|
|
// distance_cm = echo_duration/2 * 0,0344 or distance_cm = echo_duration/2 / 29,1
|
||
|
|
distance_cm = (echo_duration/2) / 29.1;
|
||
|
|
|
||
|
|
//print this result at the screen
|
||
|
|
Serial.print("Distance in cm: ");
|
||
|
|
Serial.println(distance_cm);
|
||
|
|
|
||
|
|
//wait before next measurement
|
||
|
|
delay(250); //ms
|
||
|
|
|
||
|
|
}
|