Having sketch problems.

Question

I am having trouble with my sketch. I am using an ultrasonic distance to activate relay. Relay stays on all the time.

#define trigPin 12

#define echoPin 13

int relay2 = 2;

int i = 1000;

void setup() {

Serial.begin (9600);

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

pinMode(relay2, OUTPUT);

}

void loop() {

long duration, distance;

digitalWrite(trigPin, LOW);

delayMicroseconds(2);

digitalWrite(trigPin, HIGH);

delayMicroseconds(10);

digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH);

distance = (duration/2) / 29.1;

digitalWrite(2, LOW);

if (distance >= 25 || distance <= 2){

Serial.println("Out of range");

}

if (i >= 4){

delay(i);

(distance >= 10);

(distance <= 8);

i = i/2;

}

else {

digitalWrite(2, HIGH);

digitalWrite(2, LOW);

Serial.print(distance);

Serial.println(" in");

delay(i);

digitalWrite(2, LOW);

delay(i);

digitalWrite(2, HIGH);

i = i/2;

}

delay(2000);

}

Robert Peter Oakes · Answer

I dont understand why you have all the DigitalWrite(2, low) and (2,high) statements the way you do, the relay if it is mechanical will never responsd that quickly

these two statements seem obsolete as they do nothing

(distance >= 10);

(distance <= 8);

and your comparison to i starts out with i=1000 and will not execute the relay pulse untill i<=4 so that means i/2 +2000ms delay each time as I goes from 1000 to 3 so thats about

(1000, 500, 250, 125, 62, 31, 16, 8, 4) 9*2000 = 20 or more seconds before the relay will do anything

Then your delays get so small due to using i and never resetting it once it gets to almost zero from 1000 that the relay will apear to sit energised or not depending what a High value on the output does

So now we know the issues, what is it you really want the code to so, use a flow chart or plain english description (Not Code)

Robert Peter Oakes · Answer

So have a go at correcting the program based on my feedback above and then let me / the thread see where your at and we can help some more, we (The community and Top Members) try not to do it for you as then you will not learn much