Normally the ultrasonic sensor (HC-SR04 sensor) works as expected, but when I close the relay then it stop working.
The relay is for another job, nothing related to the ping sensor yet..
This is the code:
/*
* created by Rui Santos, http://randomnerdtutorials.com
*
* Complete Guide for Ultrasonic Sensor HC-SR04
*
Ultrasonic sensor Pins:
VCC: +5VDC
Trig : Trigger (INPUT) - Pin11
Echo: Echo (OUTPUT) - Pin 12
GND: GND
*/
#define relay1 10
int trigPin = 11; //Trig - green Jumper
int echoPin = 12; //Echo - yellow Jumper
long duration, cm;
String cmd;
void setup() {
//Serial Port begin
Serial.begin (9600);
Serial.println("Initializing Relay...");
pinMode(relay1, OUTPUT);
Serial.println("Initializing Ultrasonic sensor...");
//Define inputs and outputs
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop()
{
if (Serial.available() > 0) {
// read the incoming byte:
cmd = Serial.readString();
if (cmd == "relayOn"){
//relay normally closed - ultrasonic sensor stop working here
digitalWrite(relay1, LOW);
}else if (cmd == "relayOff"){
//relay normally open
digitalWrite(relay1, HIGH);
}
}
// The sensor is triggered by a HIGH pulse of 10 or more microseconds.
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
digitalWrite(trigPin, LOW);
delayMicroseconds(5);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Read the signal from the sensor: a HIGH pulse whose
// duration is the time (in microseconds) from the sending
// of the ping to the reception of its echo off of an object.
pinMode(echoPin, INPUT);
duration = pulseIn(echoPin, HIGH);
// convert the time into a distance
cm = (duration/2) / 29.1;
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(250);
}