This arduino compatible shield came with 2 status leds... - Page 1
Forum section: electronics / general

author: rollatorwieltje
author_rank: Unknown
timestamp: December 18, 2014, 12:48:58 pm
content: SpaceX could use this one for their upcoming landing test, it can be seen from orbit

author: c4757p
author_rank: Super Contributor
timestamp: December 18, 2014, 02:34:56 pm
content: Nobody knows how to select LEDs or resistors for them anymore. Exhibit A...

author: SeanB
author_rank: Super Contributor
timestamp: December 18, 2014, 05:22:01 pm
content: Some of the ultra high efficiency LED's are incredibly bright at less than 1mA of current, some I used in an indicator running at 5mA are bright enough to be visible in dirct sun, and will cast a shadow in twilight indoors. I figured that was better than the barely visible neon lamp, and lifetime would be a lot more.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 18, 2014, 06:40:22 pm
content: Back in the day, LEDs sucked, and you ran them at the rated 20mA or whatever, because you HAD to!People seem to forget the original reason...That or....Gnaw, see, it's just meant to be daylight-viewable! During a supernova! In the middle of an asteroid impact!Tim

author: zapta
author_rank: Super Contributor
timestamp: December 18, 2014, 07:28:05 pm
content: Quote from: c4757p on December 18, 2014, 02:34:56 pmThis is what Light Dims are for

author: ajb
author_rank: Super Contributor
timestamp: December 18, 2014, 09:33:41 pm
content: Quote from: SeanB on December 18, 2014, 05:22:01 pmA while ago I was building a little test board and grabbed some 3mm red and green LEDs we had lying around (both from the same manufacturer and seemingly from the same family). After some testing, I found that to get them reasonably matched and non-blinding I had to run the red at ~3mA, and the green at ~40uA!Someone here apparently got annoyed that our techs would often forget to turn off a piece of battery powered test equipment when they were done with it. His solution was to replace the power indicator with the most blindingly bright 5mm blue LED he could find. Which lead to our techs just covering up the LED, and if anything beinglesslikely to remember to turn it off...

author: free_electron
author_rank: Super Contributor
timestamp: December 18, 2014, 09:39:15 pm
content: quick , somebody invent a led circuit with a photodiode feedback controlled current source.that way the led will always be at the specifed brightness ( read back using photodiode ) irrespective of applied voltage.now you can sell led's with a given fixed optical power and we could away with brifghtness fluctuations and series resistor calculations altogether.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 19, 2014, 06:12:48 pm
content: Or even better, some isolation between chip and control, so it monitors ambient lighting conditions and self-dims like TVs do.Tim

author: rollatorwieltje
author_rank: Unknown
timestamp: January 01, 2015, 07:08:06 pm
content: It gets even worse with this board...None of the IO pins are actually wired out5V strip shorts out on the USB connectorReset button interferes with 2 pins, so you can't stack another board on itSparkfun, what were you smoking when you made this? I mean, Arduino itself is already a disaster, but to screw it up even more... Insane.