If statements with ultrasonic

Projects Programming
1

I am trying to set an LED on pin 8 to turn on only when the Ultrasonic sensor sees at a certain distance, but the LED is always on. here is the code

const int TrigPin = 2;
const int EchoPin = 3;
const int ledpin1 = 8;
float cm;
void setup()
{
Serial.begin(9600);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
pinMode(ledpin1, OUTPUT);
}
void loop()
{
digitalWrite(TrigPin, LOW);       
delayMicroseconds(2);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);
cm = pulseIn(EchoPin, HIGH) / 58.0; //The echo time is converted into cm
cm = (int(cm * 100.0)) / 100.0;     //Keep two decimal places
Serial.print("Distance\t=\t");
Serial.print(cm);
Serial.print("cm");
Serial.println();
if(cm > 20) {
  digitalWrite(ledpin1, HIGH);
}else if(cm < 20){
  digitalWrite(ledpin1, HIGH);
}
delay(1000);
}

Any help would be appreciated!

2

Could it possibly have something to do with this:

if(cm > 20) {
  digitalWrite(ledpin1, HIGH);
}else if(cm < 20){
  digitalWrite(ledpin1, HIGH);
}

Regards,
Ray L.

3

RayLivingston:
Could it possibly have something to do with this:

if(cm > 20) {

digitalWrite(ledpin1, HIGH);
}else if(cm < 20){
  digitalWrite(ledpin1, HIGH);
}




Regards,
Ray L.

yeah. thats where i am trying to make the led turn on from distance

4

Spoiler Alert !!!

The LED pin gets written to HIGH in both paths!

5

vaj4088:
Spoiler Alert !!!

The LED pin gets written to HIGH in both paths!

That would do it. Thanks. I'm just an idiot

6 
}else if(cm < 20){
  digitalWrite(ledpin1, HIGH);

Try

}else if(cm < 20){
  digitalWrite(ledpin1, LOW);