L LED in low state still emitting light

[dimakel]

hello
im a biggener doing my first project. Im making distance sensor project.
im using grove ultrasonic sensor.
i want the L led to turn off under certain distance and turn on above that distance.
i manged to programmer it but L led doesn't turn off completely it just emitting
very low light compare to the second state.

onst int pingPin = 13;
unsigned int duration, inches;
void setup() {
Serial.begin(9600);
}
void loop() {
pinMode(pingPin, OUTPUT); // Set pin to OUTPUT
digitalWrite(pingPin, LOW); // Ensure pin is low
delayMicroseconds(2);
digitalWrite(pingPin, HIGH); // Start ranging
delayMicroseconds(5); // with 5 microsecond burst
digitalWrite(pingPin, LOW); // End ranging
pinMode(pingPin, INPUT); // Set pin to INPUT
duration = pulseIn(pingPin, HIGH); // Read echo pulse
inches = duration / 74 / 2; // Convert to inches
Serial.println(inches); // Display result
delay(1000); // Short delay

if (inches < 10)
{
digitalWrite(pingPin, LOW);
}
else
{
digitalWrite(pingPin, HIGH);
}
}

[anon73444976]

We can't see your code.
We can't see your schematic.

[dimakel]

added to the original massage
thank you

[UKHeliBob]

@dimakel

added to the original massage

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[anon73444976]

Can you confirm you're controlling the LED and the ranger . . .using the same pin?

[gcjr]

@dimakel

pinMode(pingPin, OUTPUT); // Set pin to OUTPUT
digitalWrite(pingPin, LOW); // Ensure pin is low
delayMicroseconds(2);
digitalWrite(pingPin, HIGH); // Start ranging
delayMicroseconds(5); // with 5 microsecond burst
digitalWrite(pingPin, LOW); // End ranging
pinMode(pingPin, INPUT); // Set pin to INPUT

the code above turns the LED on/off each iteration of loop().

seems like you only want to do this once, in setup()

[Idahowalker]

How to properly post code see below:

@dimakel

onst int pingPin = 13;
unsigned int duration, inches;
void setup() {
Serial.begin(9600);
}
void loop() {
pinMode(pingPin, OUTPUT); // Set pin to OUTPUT
digitalWrite(pingPin, LOW); // Ensure pin is low
delayMicroseconds(2);
digitalWrite(pingPin, HIGH); // Start ranging
delayMicroseconds(5); // with 5 microsecond burst
digitalWrite(pingPin, LOW); // End ranging
pinMode(pingPin, INPUT); // Set pin to INPUT
duration = pulseIn(pingPin, HIGH); // Read echo pulse
inches = duration / 74 / 2; // Convert to inches
Serial.println(inches); // Display result
delay(1000); // Short delay

if (inches < 10)
{
digitalWrite(pingPin, LOW);
}
else
{
digitalWrite(pingPin, HIGH);
}
}

pinMode(pingPin, OUTPUT); // Set pin to OUTPUT << belongs in setup

What LED is doing the bad thing?

Make it simple on yourself use the NewPing library.

[6v6gt]

You appear to be using pin 13 for two conflicting purposes:

1. As a led indicator.
2. As an input pin for your sensor.

The glowing led is probably being fed through the pin pull up resistor.
Use separate pins for these two purposes.

[TomGeorge]

Hi,
Can you please post a circuit diagram of your project?
A hand drawn schematic would be fine, just make sure you label your components and pin names.

Thanks.. Tom....

[dimakel]

yes ,i have 3 pins
gnd
3.3v
and one goes to 13 with the L led

[dimakel]

you can in the picture that there are 4 wires going out from the sensor but only 3 going to the arduino
the white is cut
so i plugged pin 13, gnd and 3.3 v

thanks alot

[anon73444976]

@dimakel

and one goes to 13 with the L led

Why?
Why not use a pin that isn't being used by the on-board LED?

[dimakel]

because i want to turn the L LED on on a certain distance
can i light the L led but using other pin ?

[anon73444976]

But your code tells the LED to turn on or off, not the ultrasonic ranger.

[TomGeorge]

Hi,

@dimakel

because i want to turn the L LED on on a certain distance
can i light the L led but using other pin ?

The ultrasonic sensor ONLY provides the signals to detect an object, YOUR code does the calculation.
You might be better off using the "NewPing" libaray to do your range sensing .
https://playground.arduino.cc/Code/NewPing/
And look that some of the examples.

Tom..