Led self dimming and brightening

Projects Programming
1

hello, im very very new to arduino so please be patient.
i just learned for loops so i thought of coding an led that brightens and dims by itself, im able to make it upto the max brightness but cant seem to get it down. i think this will be more achievable with a while loop but i want to see what a for loop can do. heres the code:



int j;

int wait=500;

int mypin=9;

int bright=255;

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

pinMode(mypin,OUTPUT);

}

void loop() {

// put your main code here, to run repeatedly:

for(j=1;j<=bright;j=j+1){

analogWrite(mypin,j);

delay(wait);

}

for(j=bright;j>=0;j=j-1){

analogWrite(mypin,j);

delay(wait);

}

}
2

What makes you say that the LED is not dimming ? Do you know how long it takes the LED to reach full brightness before starting to dim ?

Try printing the value of j before writing it to the LED so that you can see what is being written

3

Change the value of wait from 500 to 50 or 20 and see what happens.

What value of current limiting resistor did you place in series with the LED?

4

changing wait to 50 is working thanks a lot. is it dependent on the fact that for 1/255 units, half a second is wayy too long? and the resistor is 330 ohms. thanks again!!

5

youre right. i indeed underestimated the time that it needs to get to 5 volts.

6

I am glad that you got there

Printing the values as they were used would have given you a big clue as to what was going on

7

With wait = 500, it takes about 128 seconds, or over two minutes to reach full brightness.

8

I'll definitely keep that in mind from now on

9

Idk why I didn't think of applying basic unitary method on this, i thought half a second is fast regardless of where it's used.

10

That is true, but you used it 255 times !

11

i started the arduino lessons after doing tons of integration and was soo ready to not use even a ounce of maths but well 1/2 of 256 is still math lol

12

I think you mean 1/2 times 256

13

A half of 256 is 128, it's a matter of grammatical phrasing, We're both right.

14

Next, read about millis() delays.
You’ll thank us later !

15

I'll work on it, thank you!