None of my HCSR04 sketches work. I think my board is broke.

Hi guys. I seemed to have had this problem before and don’t know what to do. I’ve tried uploading the follow sketch multiple times and my TX light just keeps blinking. I tried to upload the blink sketch to see if maybe it was my board and it works. I thought maybe it could be my sensor but I tried 3 different sensors and none of them are working and I still get the blinking TX light. Can someone possibly see if they get the same problem? Thank you in advance.

Code I’m using.

/*
 HC-SR04 Ping distance sensor:
 VCC to arduino 5v 
 GND to arduino GND
 Echo to Arduino pin 7 
 Trig to Arduino pin 8
 
 This sketch originates from Virtualmix: http://goo.gl/kJ8Gl
 Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html
 And modified further by ScottC here: http://arduinobasics.blogspot.com.au/2012/11/arduinobasics-hc-sr04-ultrasonic-sensor.html
 on 10 Nov 2012.
 */


#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 50; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
 Serial.begin (9600);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
}

void loop() {
/* The following trigPin/echoPin cycle is used to determine the
 distance of the nearest object by bouncing soundwaves off of it. */ 
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 
 
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 
 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;
 
 if (distance >= maximumRange || distance <= minimumRange){
 /* Send a negative number to computer and Turn LED ON 
 to indicate "out of range" */
 Serial.println("-1");
 digitalWrite(LEDPin, LOW); 
 }
 else {
 /* Send the distance to the computer using Serial protocol, and
 turn LED OFF to indicate successful reading. */
 Serial.println(distance);
 digitalWrite(LEDPin, HIGH); 
 }
 
 //Delay 50ms before next reading.
 delay(50);
}

Ian_McElrath:
I've tried uploading the follow sketch multiple times and my TX light just keeps blinking. I tried to upload the blink sketch to see if maybe it was my board and it works. I thought maybe it could be my sensor but I tried 3 different sensors and none of them are working and I still get the blinking TX light.

That's the expected behavior. The sketch prints the distance to the Serial Monitor, which causes the TX LED to blink.

Have you tried opening Serial Monitor and setting it to 9600 baud (as determined by Serial.begin() in your sketch)?