Author Topic: Are all LEDs the same quality? (Read 4851 times)

rackoon · « **on:** January 27, 2006, 11:12:34 pm »

Does any one know if all LEDs are created equal. I want to lite up my new clear button and it seems that one can buy a lot of leds from Taiwan for real cheap off eBay. Are these total crap or are all leds created equal.

cholin · « **Reply #1 on:** January 27, 2006, 11:31:36 pm »

No.

MCD is the brightness, that's a big factor in LEDs. For lighting up buttons, most times they're too bright, so go on eBay, but 100 for 5 bucks and you will STILL have to file them down to diffuse the light because they're too strong for buttons.

ShinAce · « **Reply #2 on:** January 27, 2006, 11:33:01 pm »

No. All high intensity(clear bulb) will handle 20ma nominal, usually 25 max. For general use, they're all comparable. However, some companies manufacture leds with currents up to 100 mA, laser led's, and much more.

edit: mcd is not necessarily the best measure of brigthness. You need to also look at the angle. Bigger angle and low mcd = lots of light overall. A tiny angle and high mcd = concentrated light, possibly too concentrated.

cholin · « **Reply #3 on:** January 27, 2006, 11:37:37 pm »

Yeah, but for general purposes, youre lighting a button and the material inside the button will reflect some light towards the center.

Not to get into physics and crap, but in general its MCD... and get el-cheepo ones because they're more than enough.

rugby1 · « **Reply #4 on:** January 27, 2006, 11:43:11 pm »

I bought 50 LEDs (10K MCD) on Ebay for $ 0.85.... very very bright, but I just grabbed some fine grit sandpaper and scuffed them up and they light my Happ Translucent buttons up perfect. I would recommend 7 to 8K MCD though.... 10K can be a bit much

These were fine... they all have worked (except the 2 I burned out by plugging them into my 12 v instead of 5 v....oppps)

cholin · « **Reply #5 on:** January 27, 2006, 11:45:07 pm »

:O How much was shipping? They tend to sell for like a buck with mysterious 9 dollar shipping...

RandyT · « **Reply #6 on:** January 27, 2006, 11:48:37 pm »

Quote from: cholin on January 27, 2006, 11:37:37 pm

Not to get into physics and crap, but in general its MCD... and get el-cheepo ones because they're more than enough.

Cholin,

Do a search for a post from me on LED brightness. I actually gave some examples at one time that show just how unimportant that MCD rating is.

MCD alone does not indicate the amount of "luminous flux", which is far more important for things like lighting buttons.

RandyT

rugby1 · « **Reply #7 on:** January 28, 2006, 12:04:24 am »

I bought them for like $0.85 cents but your right the shipping was stupid... I believe it was $10 or so. I live in Germany too so that might have had something to do with it. I also looked at LED's at radio shack a few months ago and they were almost $2.00 EACH!!!!!!!! I'll pay the $10 shipping over the $100 it would have been at RS.

rugby1 · « **Reply #8 on:** January 28, 2006, 12:13:49 am »

Cholin,

You might also want to consider these products: (Bows to Randy T and repeats "we're not worthy")

http://www.arcadepanels.com/gib/index.php?main_page=product_info&cPath=83&products_id=240

http://www.arcadepanels.com/gib/index.php?main_page=product_info&cPath=83&products_id=238

http://www.arcadepanels.com/gib/index.php?main_page=product_info&cPath=82&products_id=239

cholin · « **Reply #9 on:** January 28, 2006, 05:56:52 pm »

Yeah Ive seen Randy's products... then again, I really dont think theyre much special so I kept my mouth shut. I *really* want those buttons though! I was gonna grab a ton of them but I held off with the intention of buying custom PCB's first, then using the little money income to buy the buttons.

I already have my LED's though and im just saying that almost ANYTHING will be too bright. I have 600 MCD green and red ones and they're pretty damn good too for lighting buttons... so I guess its not that important...

The LED button PCBs are no biggie to me... although I do respect how Randy does come up with these ideas. Im sure for the most part it will be a good hit because people do want those. Im much more of a save money, DIY kinda guy...

Silver · « **Reply #10 on:** January 29, 2006, 11:17:34 am »

Is sandpaper the best way to diffuse the light given off?

I've got a pile of bright LED's (free off a friend!) but they are all 20 degrees (ie quite focussed). I was wondering if there is any (cheap) substance I could put over the top of the LED when its in the button to diffuse the light?

PS LED-Whiz just arrived. Very happy about that!

ShinAce · « **Reply #11 on:** January 29, 2006, 03:44:23 pm »

Flattening the tip would be the best. With a fine grinding wheel, flatten the concave part, but not entirely. Buffing the flattened part may help afterwards.

Sandpaper to scuff the surface is not the most effective.

JoyMonkey · « **Reply #12 on:** January 29, 2006, 07:16:12 pm »

I'm by no means an expert, but from reading over a few threads here's my general understanding of it for anyone still wondering...

A high MCD is great, but if the viewing angle is too small and you have the LED positioned so it's pointing straight up you'll end up with a big hotspot in the center of the button and not much light will show through the button's bezel. This is especially bad for buttons that are very transparent (whoever's playing will be blinded if they look directly at the buttons!)
With a higher viewing angle the light is more evenly distributed through the whole button and you end up with less of a hotspot and more light in the bezel.
Here's a drawing to show what I mean...

I'm using SuperBright RL5-R3545 (3500mcd, 45degree) red LEDs and have them mounted like this in translucent red buttons and I think they light the whole button up great. I also have a few translucent leaf-switch buttons that I'm going to try out and see how lighting them with two LEDs on each side (like how MikeQ shows it here) compares to lighting a Happ style button with one LED in the center.

juggle50 · « **Reply #13 on:** January 30, 2006, 02:24:35 am »

Hey Joy Monkey,

I just ordered mine and they are 30 degrees. Do you think thats not wide enough. They have pretty bright mcd around 4000.

JoyMonkey · « **Reply #14 on:** January 30, 2006, 09:44:03 am »

Quote from: juggle50 on January 30, 2006, 02:24:35 am

Hey Joy Monkey,
I just ordered mine and they are 30 degrees. Do you think thats not wide enough. They have pretty bright mcd around 4000.

Like I said, I'm not an expert, but I'd say you might be better off mounting two of those LEDs per button and have them pointing into the button's edges like in MikeQ's setup.

As Randy has pointed out before, when you're mounting the LEDs so they're pointing straight up through the button (like in the above drawing) the most important factor in choosing an LED is it's luminous flux, which is determined by it's MCD and beam angle.

Here's a nice calculator to help you easily figure out an LEDs luminous flux:
http://led.linear1.org/lumen.wiz

While I'm at it, here's another useful calculator for determining what size resistor each LED needs:
http://led.linear1.org/1led.wiz

juggle50 · « **Reply #15 on:** January 30, 2006, 12:45:33 pm »

Well shoot,

Now I don't know what to do. The blue ones I ordered from the superbright's website are:

4600mcd with 30 degree angle which equals: .985 lumens

my only other option would be

2500mcd with 45 degree angle which equals: 1.196 lumens

My problem is I don't know what that means. Will I notice a difference and should I reorder. I am lighting up blue translucent lights and trackball. I would like to use only one per button if possible.

cholin · « **Reply #16 on:** January 30, 2006, 06:27:40 pm »

I wouldnt worry about it. They're definately bright enough, and 30 degrees isnt too bad. Its something like that where you use the flattening technique and sandpapering them. Don't worry too much...

juggle50 · « **Reply #17 on:** January 30, 2006, 06:29:16 pm »

thank you

rugby1 · « **Reply #18 on:** January 31, 2006, 11:03:29 am »

ummmmm..... WHAM avatar?

? For the love of god, why WHAM?

quarterback · « **Reply #19 on:** January 31, 2006, 01:48:06 pm »

Quote from: rugby1 on January 31, 2006, 11:03:29 am

ummmmm..... WHAM avatar?? For the love of god, why WHAM?

Maybe he wants you to wake him up before you go-go?

mahuti · « **Reply #20 on:** January 31, 2006, 02:21:12 pm »

Rugby1, DUDE, you are either ON the bus or OFF the bus... which WAY is it GONNA be.

brian23 · « **Reply #21 on:** January 31, 2006, 03:21:53 pm »

Judging by JoyMonkey's links, you'd be better off getting the 2500mcd w/ 45 degree angle. The 2500 mcd looks to have more lumens, plus a better viewing angle.

Quote from: juggle50 on January 30, 2006, 12:45:33 pm

Well shoot,

Now I don't know what to do. The blue ones I ordered from the superbright's website are:

4600mcd with 30 degree angle which equals: .985 lumens

my only other option would be

2500mcd with 45 degree angle which equals: 1.196 lumens

My problem is I don't know what that means. Will I notice a difference and should I reorder. I am lighting up blue translucent lights and trackball. I would like to use only one per button if possible.

juggle50 · « **Reply #22 on:** January 31, 2006, 03:34:31 pm »

Hey, don't mess with Wham. They are probably the most influencial band of our generation. The meeting of Andrew Ridgley and George Michael was like the musical genious of Chopin combining with the poetical lyrics of ee cummings.

To quote from the famous Wham Rap

"I ain't never gonna work, get down in the dirt,
I choose, to cruise.
Gonna live my life, sharp as a knife,
I've found my groove and I just can't lose."

Shakespeare I tell you.

Back to buisness. How the hell do you attach a resistor?

mahuti · « **Reply #23 on:** January 31, 2006, 03:41:07 pm »

solder.

cholin · « **Reply #24 on:** January 31, 2006, 03:51:18 pm »

LOL! Well, someone's new to this! Im guessing you wont have a solderring iron or some solder lying around, so your next bet would be to twist them togehter really really tight, then hot glue it so it never moves. Wont last you a lifetime, but it'll be funny anyways

rackoon · « **Reply #25 on:** January 31, 2006, 04:25:28 pm »

Well I ended up buying 100 UV leds through eBay. 1$ plus $11 shipping from Hong Kong.
I believe that they are 3mm, 2000mcd, 15degree view angle. I'm going to use almost all of them. I will experiment with the sandpaper and grinding the bulb flat.

I have 24 buttons and a recessed diamond plate kick plate at the bottom that I want to bounce UV light off. I am working on a three sided cocktail and might shine some down under each CP also. Heck, I would mount a freak'en disco ball to it if my wife would let me..well maybe not but I am trying to recreate the arcade feel that I used to experience back in the 80's. UV black lights were quite popular.

Any way I will post pics when I get far enough.

juggle50 · « **Reply #26 on:** January 31, 2006, 05:14:05 pm »

Cool idea racoon.

I do have a soldering iron. I just suck at it and was just seeing if there was a way around it. However, I'm running about 10 of the same lights in parrallel and the way I understand it I only need one resistor right?

cholin · « **Reply #27 on:** January 31, 2006, 06:21:15 pm »

rugby1 · « **Reply #28 on:** February 01, 2006, 03:57:13 pm »

Quote from: mahuti on January 31, 2006, 02:21:12 pm

Rugby1, DUDE, you are either ON the bus or OFF the bus... which WAY is it GONNA be.

Well, I'm definately off that bus.... gonna go get on the little yellow special kids bus first

RandyT · « **Reply #29 on:** February 01, 2006, 05:02:14 pm »

Quote from: rugby1 on February 01, 2006, 03:57:13 pm

Quote from: mahuti on January 31, 2006, 02:21:12 pm
Rugby1, DUDE, you are either ON the bus or OFF the bus... which WAY is it GONNA be.

Well, I'm definately off that bus.... gonna go get on the little yellow special kids bus first

I'd rather lie under the wheels......

RandyT


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