External leds connected to pin, not working

[hrafnagudh01]

Hello everyone.
First of all, apologies if I made some formal mistake, I am not used to forums.
Also, I am very new to putting my hands in electrical stuff so I sometimes struggle with specific names.
Secondly I messed something up with the forums command so maybe this thing will pop up twice, awfully sorry about that...

I have bought an Elegoo super starter kit and having fun with it.
Today, the external leds connected to pins are not working anymore.
I do not have a measuring tool to check voltage, so I started some experiments.

The code I know is right, as it worked until yesterday.

I tried to plug different areas of the breadboard, different pins, changing wires, always making sure the long leg of the led is towards +, and using both a220, 330 and as an extreme, no resistor. No results.

I tried to check if led was dead by connecting it directly between 5v( and another time 3.3v) and ground. It lights up.

I used the same physical circuit, wires, pins, resistor, with a different program of course, to make sounds with a buzzer. The buzzers buzzes (one of my first experiment was making a greensleeves sounding buzzer).

LED connected via wire between 5v and GND will NOT work.

Lastly, if in the circuit I bypass the resistor, making the 5v wire touching directly the led, and/or connecting it to the breadboard without resistor, the led still won't light up, but the internal led will flicker and turn off, and sometimes the pc will sound the "disconnected device sound".

I searched online but the closest one was a case of led reversed in the circuit. Just for try sake I reversed mine but still, won't work.

Thanks in advance to whoever will help me solve this bizarre problem. I will keep try in the meantime.

[jim-p]

@hrafnagudh01

and as an extreme, no resistor

That will damage the Arduino.

LED connected via wire between 5v and GND will NOT work.

That will burn out the LED.

Never connect an LED to anything without a current limiting resistor

[ptillisch]

Hi @hrafnagudh01.

@hrafnagudh01

I tried to check if led was dead by connecting it directly between 5v( and another time 3.3v) and ground. It lights up.

@hrafnagudh01

LED connected via wire between 5v and GND will NOT work.

These two sentences seem to contradict each other. In the first sentence, you indicate that the LED does light when you connect it to 5V and ground, but then in the second sentence you indicate that it does not light when you do that.

Please provide more information to help us understand what you meant by this.

@hrafnagudh01

if in the circuit I bypass the resistor, making the 5v wire touching directly the led, and/or connecting it to the breadboard without resistor, the led still won't light up, but the internal led will flicker and turn off, and sometimes the pc will sound the "disconnected device sound".

This is a bad idea. You should always use a current limiting resistor with LEDs. If you don't, you could burn out the LED.

You can also do permanent physical damage to the Arduino board. This is more likely if you have the LED connected to one of the digital pins on the board, since they can only handle a small amount of current draw. The 5V pin on the board can handle a lot more current draw, so the result you describe of it causing the board to disconnect is a bit unexpected.

[PaulRB]

@hrafnagudh01

bypass the resistor, making the 5v wire touching directly the led, and/or connecting it to the breadboard without resistor, the led still won't light up, but the internal led will flicker and turn off, and sometimes the pc will sound the "disconnected device sound".

That sound is often made by the PC if the USB device draws too much current (>500mA).

Maybe your led is burned so badly from being connected without a series resistor, that it melted internally and is now causing a short-circuit.

Your leds and your Arduino are now suspected of damage. Replace all of them. And never connect an LED without a series resistor in future.

Or ...

@hrafnagudh01

I do not have a measuring tool to check voltage

Get a multimeter. It doesn't have to be an expensive one. Just something costing 10~20 £/€/$.

Electronics without a multimeter is like fumbling in the dark.

[hrafnagudh01]

Thank you all for the answers.
I have "solved" the problem.

Turns out the led legs were too close, so leg after leg onto the circuit wouldn't work, but separate them leaving a two holes in the middle, o make them one after the other but on different rows, and it works!
And now that I thing of it, the same thing happened to me when I was trying the tilt sensor. Legs too close even with no breadboard but just two wires, no signal.
Why is that?

Luckily it seems I don't have to replace anything, for today at least

Weird thing though

Edit, now that I think of it, I made a mess with breadboard circuitry I think. They were not working because at the end of the day long leg and short leg were on the same piece of metal. Dumb medal to me I suppose.
Well, mistakes have to be made to learn. Thanks again to all, see you to my next weird way to destroy everything