Hey All,
I've been busy at work on my AMANDA-LDR based rover, making alot of progress. But I've noticed a problem with some of my superbright LEDs. They dim. When I fire one up, it will be fairly bright, but will quickly start getting dimmer until it's not emitting any light at all. If I wait 30 seconds and fire it up, it will still be fairly dim. If I wait 5 minutes and try again, it will be bright, but will still dim. This is consistant with multiple power supplies (picaxe, direct V). Does this mean the LED is just giving out? I hope not, since I've already got it superglued and wired to my chasse ...
Are you pushing the limits
Are you pushing the limits on what it can take? If so it may be getting too hot. To test it out put it somewhere cold or wrap some wet papertowel around it (careful not to tought the circuit!) and see if it still dims. Or increase the resistance slightly. The only time I’ve heard of LEDs dimming is due to heat from too much current.
that’s what i thought at
that’s what i thought at first, but i’m powering it with the picaxe outpin, through 2 330 resistors. I’ve got another LED right next to it powered the same way that’s super-bright …
Part number for the LED? For
Part number for the LED? For a datasheet. And are the 2 resistors in series or parallel to the LED?
Thinking if resistors are parallel, might be trying to draw too much current from the PIC pin, overheating the PICAxe.
Heat possibly causing the super glue to be conductive? Maybe if contacting the pins, don’t know.
no part number
1. No part number. I got it from a wholesaler who didn’t have any packaging. weak, i know. but it’s 1 of four, and the other 3 work fine.
2. Resistors are series (my tests had 1, but I left out the one needed on the project board).
3. There is a lot of superglue touching the leads. Cyanoacrylate. Maybe I’m accidentally making a bypass with the glue? But the dimming is a process. It gets continually dimmer.
At this point, I’m assuming that the LED is just a piece of crap. I’ll get a new one, but I wonder if the glue could be a problem.
burned
Yeah, it’s definately screwed. Thanks for the knowledge. Know a good un-superglue trick? Here are pics.
brute force
Since the LED is garbage anyway, I’d just attack the glue and LED with a knife and some pliers. Maybe crush the led with the pliers first, then use knife and maybe sandpaper to get the small parts of.
Superglue gets really hard, but often gets quite brittle, so you could trying to just snap it of/pull at an angle…
you could snip off the LED
you could snip off the LED and use what is left of its leads to solder a new LED on.
Thanks all! I’ll keep you
Thanks all! I’ll keep you updated in my bummer blog.
Super glue the cyno family
Super glue the cyno family is great stuff.2000lb strenght. To get it loose use MEK knwon as methyl ethyl keotone. Acetone is a diluted version of mek and may do the trick. WARNING MEK EATS PLASTIC.WARNING MEK IS FALMMABLE.WARNING MEK IS NOT GOOD TO BREATH MUCH OF. WARNING MEK IS…ahhh heck it is bad stuff but used carefully it will work in small quantities. Found at all local harware paint stores.as well as auto supplys too. Course the dremel over there you know the one with the cord remote speed etc…sure would be handy with the right burr on it to dig it all out!!!
