Arduino Nano LEDs pin failure

[_Nate_]

I am working on a sound-reactive led system and things are not going as planned. I have my Arduino nano hooked up to two separate strands of 5 LEDs. One strand uses pins 2-3-4-5-13 and the other uses 6-7-8-9-10. Here is the issue: the second LED strand lights up flawlessly with no issues. The first one lights up very dimly if at all. When testing the LEDs with a different power source to see if they were just bad leds, all 5 lit up fine. I tested all ground continuities and have concluded that the problem lies with the output. So why is the output so different from those specific pins?

 

[Bluejets]

Show a complete diagram of your layout including power supplies and or batteries used.

 

[_Nate_]

Show a complete diagram of your layout including power supplies and or batteries used.

I tried to make a diagram but it didn't save D;

The pins of the arduino all go to the 5v of the two different strips. Depending on what color I want from each led, that color is connected to a common ground for all 10 leds. The only power source is the 5v usb cable into the nano.

 

[kellys_eye]

Do you have series current limiting resistors on each LED?

What current are you running the LEDs at?

Are you sure they are all positioned correctly i.e. polarity?

Are you sure they are all working ok? Send code to LEDs individually to see if they light correctly.

 

[_Nate_]

Do you have series current limiting resistors on each LED?

What current are you running the LEDs at?

Are you sure they are all positioned correctly i.e. polarity?

Are you sure they are all working ok? Send code to LEDs individually to see if they light correctly.

So all the power, as I've stated, is from the digital pins of an Arduino Nano. When testing the led's with an external power source by applying the positive voltage straight from the pin and the negative to the common ground, they light up fine. With my program I have written, the led's light up in order with a 50ms delay and then all turn off.

 

[kellys_eye]

If you apply a NON CURRENT LIMITED supply to any LED you will fry it...... i.e. if you don't use a series resistor it's toast (with a possible exception of using a voltage lower than the LED's forward voltage).

If you are using LEDs with built-in current limiting resistors you're OK but I suspect the only current 'limit' you have is the maximum that the Arduino port(s) can supply i.e 40mA (which in itself will quickly ruin any 'normal' LED).

We need more details - LED type, circuit layout etc.

If you are using the LEDs without a resistor you have likely damaged one (or more) internally. Try rebuilding the circuit but add a series resistor (of around 470Ω) to each LED. You may need to use new LEDs to fix the problems you're having though.

 

[(*steve*)]

LEDs that have been damaged can exhibit a number of of behaviours short of not working at all:

1. Being dim
2. Exhibiting a turn on delay (can be a second!)
3. Requiring a higher current to turn on.

The fact that a LED lights does not mean it's not damaged.

In addition, it's possible to damage the ports of the microcontroller. Hopefully you haven't done that (it tends to require a little more effort).

 

[BobK]

It is still still unclear what you are doing. Everyone here is assuming you have 10 individual LEDs, each connected to a different output pin.

But, first you refer to two strands of LEDs, and later you refer two LED strips.

I think you are hooking up one strip to 5 outputs and a second strip to another 5 outputs, which is reasonable to get the needed current.

If that is the case, I am guessing that your problem is a software bug. On the dim strip, either some of the pins are configured as inputs, or, worse, some are outputting high and some low.

Bob

 

[_Nate_]

Problem solved. The wires were bad.