Help with LED specs and bulk orders

[cyapps]

I need to buy some leds in bulk but I am haven't had much hands on experience with any except Button Blasters from groovy game gear. The problem is that GGG doesn't seem to offer any discounts for bulk ordering so I figured I would check out ebay and I came across "Package of (100) 5mm Super Bright Blue 13,000 mcd C-LEDS SIGNATURE SERIES LEDs" for $14.97 shipped. At .15 a piece I figured that was a good price range but can anyone tell me the specs on the Button Blasters or will I just have to order these and compare. They don't have to be as good as the Button Blasters but if they are close enough then that is what I am looking for. If you know of a better source for bulk LEDs please share.

Specifications of LEDs from ebay:
Size (mm) : 5mm
Lens Color : Water Clear
Reverse Current (uA) : <=30
Life Rating : 100,000 Hours
Viewing Angle : 20 ~ 25 Degree
Absolute Maximum Ratings (Ta=25°C)
Max Power Dissipation : 80mw
Max Continuous Forward Current : 30mA
Max Peak Forward Current : 75mA
Reverse Voltage : 5~6V
Lead Soldering Temperature : 240°C (<5Sec)
Operating Temperature Range : -25°C ~ +85°C
Preservative Temperature Range : -30°C ~ +100°C

[Blanka]

13000 mcd is pretty good for a 30mA LED. I've one of the brightest here and they are 130000mcd at 350mA. You don't want to put that in a button, its suitable for a head light of a bicycle! I think 5000mcd would be good enough for buttons. So I guess your deal is great. Strange your specs don't mention forward voltage. With forward current the most important specs.

[cyapps]

Thanks, I found the forward voltage specs and they are 3.0-3.4v / 24mA, not sure why they list 30mA on the other part. You can view the auction here Here

[cyapps]

Anyone else have any experience with leds?

[Franco B]

They seem very similar specs to the bulk super bright blue LEDs I have bought from eBay. Mine were rated at 13,000mcd at ~30mA.

All of them have been fine that I have used so far. Some people have voiced there concerns about the lifespan of cheap LEDs but I'm not overly concerned if I do have to replace them down the line.

They are very bright though, you would probably get away with a lower MCD, as Blanka said somewhere around 5000MCD would suffice.

I don't know what buttons you are using but if you are using clears/translucents I would definitely advice using GGG's diffuser discs ad the LEDs have a very narrow viewing angle and the diffsuers help to light the buttons evenly and avoid you being blinded

I have a couple of videos of the LEDs I bought in action in my Cocktail thread. I cant see/link to youtube videos at work but you should be able to see them in my PA thread somewhere around [here].

[Bender]

I've been looking for some of these
thanks for the link and the info everyone

I bought some white wide angle ones and some RGB ones
I'll let you know how they are

[Blanka]

BTW, if they are too bright, you can always dim them with the PWM modulation of the LED-wiz.

[ulao]

BTW, if they are too bright, you can always dim them with the PWM modulation of the LED-wiz.

- I dont know what kind of LEDs you guys are buying but to dim an LED you change or add a resistor. Even if it has an internal one you can add to it.I buy my products off ebay, but that is be cause it kills mouser pricing.

 Like "Grab Bag Bulk LEDs May incl White, Blue, Red, Green LED" off ebay for a penny.

or "100PCS MegaBright Blue LED 5mm 13000 mcd!Car DIY!Free/R" for 17.99 (74.99 for 1000)

[Franco B]

We're just using 'standard' LEDs and resistors generally with a 5v source (LED Wiz etc). You could lower the maximum brightness using a higher value resistor but you may as well use the lower value resistor and use the LED Blinky software to set the brightness. That way you could increase the brightness if required for a certain LED task/event. If you limit the LED with a higher value resistor you will not be able to increase the brightness if you wish to do so without swapping the resistor. 

[Blanka]

Limiting the brightness of a LED with resistors is a pain in the ass. They have no linear behaviour like a bulb. PWM is the way to give LED's different levels of brightness, nothing else.

[RandyT]

MCD values are nearly useless for comparing LEDs for pushbutton lighting applications.

Luminous Flux..........Luminous Flux..........Luminous Flux..........Luminous Flux..........

You want wide angles.  The narrow angle LED's concentrate the light more, and therefore have high MCD ratings.  So the LED with these high ratings won't be "too bright" it will be "too focussed" and too bright in a small spot.  Not what you want.

RandyT

[Franco B]

Are you saying your diffuser inserts are no good then? 

They work very well for me 

It would have cost me $60 in blue button blaster LEDs for my cocktail.

I got 200 blue LEDs of ebay for $30 and it was $6 for 20 of your diffusers. I will also still have ~80 LEDs leftover.

[RandyT]

Are you saying your diffuser inserts are no good then? 

Heh.  Not at all.  However, the less work the diffuser needs to do, the better job it can do.  Even with a wide angle LED, one would probably still want some kind of diffuser to keep the glare down.

I'm simply saying that people tend to look at only an MCD rating as the indicator of LED performance, when it's really just a small part of the equation, dependent upon the application of course.

Most folks don't realize, for instance, that a 3000mcd, 40degrees view angle LED has virtually identical light output as a 12000mcd, 20 degree viewing angle LED.  So it's important to select the right combination of angle and light output for a given job, and not rely on the mcd ratings as the only basis for selection.

RandyT

[cyapps]

Thanks so much Randy that makes perfect sense about the angles. I really don't like to look at specs, especially if I don't have real world experience to compare or fully understand this stuff. These weren't going to be used for buttons (maybe a couple), I just only have the Button Blasters to compare to and I liked how they looked so I figured if I could get close to their "specs" in  bulk then I would be set but I have no clue of the specs of the Button Blasters so I just figured maybe someone more experienced with leds would have some input.

The same seller has flat wide angle leds "(100) 5mm FLAT TOP Wide Angle Blue LED 6000 mcd USA!" for even cheaper and they might actually be closer to what I want anyways. These aren't really for any specific project so I will most likely just order some and see where it takes me.