2 Spare LEDs That Seem To Be In Reverse!?!?!?!

SpokePOV kit for bikes

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dt1000
 
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2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by dt1000 »

Hello.
I was just attaching the LEDs to my SpokePOV when I noticed something weird...

The LEDs all have a flat side. This flat side also has a slightly shorter "leg".

There are two spare LEDs in my kit that have the long leg on the flat side, and, on closer inspection, look like they are constructed the wrong way round (i.e. with the flat bit on the opposite side to all the other LEDs).

Does anyone know what this means?

Thanks,
Dan

kayrock66
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by kayrock66 »

It's like finding a 4 leaf clover. It's good luck. The only way to test which indicator is right, flat side, or long lead is to hook up some juice.

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adafruit_support_bill
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by adafruit_support_bill »

Can you post a photo? I've seen 4-leaf clovers before, but never a backwards LED.

dt1000
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by dt1000 »

Here are two LEDs resting on their flat side.
You can see that the longer leg is different on each one.
Click on the image to view it full size, and you'll see that the poles are reversed as well.

Image

I've found three of these so far... which must make me the luckiest man alive! :)

adafruit
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by adafruit »

it would be a great april fools trick to pull on a friend :)

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dennyt
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by dennyt »

I also found several backwards blue LEDS with the flats on the wrong side while assembling my first kit. I went ahead and made sure the long lead was correct & ignored the flat side...

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dennyt
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by dennyt »

Aaand, epic fail! I've installed them all backwards.

Now I know, the flat is supposed to indicate the negative side of the LED. I guess the one I used to check was backwards...

Image

Dammit, I'm holding one in my hand right now with the flat oriented over the long lead.

Image

Perhaps you can update the instructions to use lead length instead of flats to orient the LEDs. And/or, check your supplier QA. Now to un-solder & flip 60 LEDs...

adafruit
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by adafruit »

yeek! OK that is really out of hand. sorry about that. we will send you a new kit, its really hard to desolder them.
email support@adafruit
check for the longer lead instead of the flat, we will also check our instructions!
we will also look into a better supplier, we've used these guys for 4 years but this is kind of BANNED :?

thejukeboxer21
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by thejukeboxer21 »

i seem to have run into the same issue as well. Most everything else has gone smoothly. My dad (a hardware electrical engineer), complimented the board layout and instructions, and everything (v 1.1). I'm working on my first kit, and the LEDs don't seem to be consistent. I was putting in the LEDs with the flat sides correctly matched up to the picture as described here: http://www.ladyada.net/make/spokepov/make.html But then I noticed that the insides of the LED weren't consistent from one to another. The lead ends were also switching from long side, to short side as sitting on the outermost part. Seems like about 50/50 for which side had the flat side. Dennyt's descriptions about correct installation helps. I've attached a picture, looks like dennyt isn't the only one with the issue, you can see that the flat bit is on the same side as the long lead, opposite of some of the others. Seems like a manufacturer defect to me.
Attachments
Flat side on side with long lead
Flat side on side with long lead
Incorrect LED.JPG (67.67 KiB) Viewed 3967 times

adafruit
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by adafruit »

the LONG lead is Positive. It seems likely the factory didnt mold the plastic right. the instructions should be updated!

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muffinman
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by muffinman »

I got a kit that had at least 15 led's with either no flat mark, or a backward flat mark molded in the plastic. Luckily I placed them all checking for the cathode lead. Whew!

This is definitely a recurring problem with that supplier, it seems.

Agent24
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by Agent24 »

I've read of electrolytic capacitors that were sleeved backwards but not backward-molded LEDs!

Guess it's another thing to be on the lookout for :P

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verris
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by verris »

I actually had this same issue with both red LEDs that came with my xbee adapter kits. Bought two kits at the same time and the red LED in both was backwards. The leg length was correct, but when looking inside, the large side was positive and the small side negative. I installed it correctly at first because I based it off leg length, but my ftdi cable was messed up and I didn't know this, so when I was looking over the adapters to see if I messed something up I noticed the large side was on positive and small side negative, and since I had clipped the leads I thought I had just put them in wrong, so I finally managed to remove them, breaking one of the two in the process, and put new ones in only to find out the one I didn't break was now in reverse.

adafruit
 
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Re: 2 Spare LEDs That Seem To Be In Reverse!?!?!?!

Post by adafruit »

never use the 'inside' of the LED to try to determine polarity, it does not have any bearing!

Use Lead Length Only Please!

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