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Newzed
01-19-2006, 03:47 AM
I've been shopping around for some low cost LEDs to mount in this large BS2E display I'm working on.· Found a possibility at Digikey - PN 67-1102.· They draw about 12ma with a 270 ohm resistor at 5VDC.· Not too bright - you would have to try them out to see if they would work for you.· Price is GREAT - 10 for $0.98 or 100 for $8.78.· That's hard to beat.

Have some slightly more expensive LEDs on the way.· I'll post the info on that when I get them.

Sid

sam_sam_sam
01-19-2006, 04:05 AM
Hi Sid

I've been shopping around for some low cost LEDs to mount in this large BS2E display I'm working on.

Here is link to 100 leds in a bag $1.98
www.mpja.com/viewallpict.asp?dept=439&main=122

Hope this helps

Sam

Bean
01-19-2006, 04:44 AM
Digikey parts # 160-1461-1

These are some bright surface mount LEDs. They are rated at 1050 mcd with a 25 degree viewing angle.

I got a whole reel of them to get a better price (< 0.08 each). Part# for the reel is 160-1461-2

Bean.

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"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

Newzed
01-19-2006, 04:47 AM
Thanks for the link, Sam.

The blue LEDs are $39.00/100.· Good price on the red - the only thing that bothers me is the luminescence - it·varies from 18 to 62mcd - not very uniform.· Also they have a $15.00 minimum - would have to find something to add on.· I'll take another look.

Thanks again

Sid

Newzed
01-19-2006, 04:54 AM
Bean, I can't use surface mount.· The LEDs are mounted via two holes drilled in a large map.· Tried to figure out a way to use SMTs but just couldn't come up with anything practical.· Thanks anyway.

Sid

PJ Allen
01-19-2006, 06:31 AM
What?· Do you need a regular supply of inexpensive LEDs?·
I've found·raging deals on LEDs at Electronics Goldmine, buying reels (1,000) and the price was < 2c ea.·
There's an excellent seller on ebay I've bought from several times, outrageous prices: superbright blue; 16,000 mcd White (100/$35); 5,000mcd Red (100/$20); and·RGBs (4-lead)·-- cwithk (look them up) and everything has·'FREE' shipping.

Post Edited (PJ Allen) : 1/19/2006 2:18:16 AM GMT

Bean
01-19-2006, 07:55 AM
Sid,
· Yeah it would probably be more trouble than it's worth, but man are those LEDs bright. About as bright as those LED flashlights (the red ones anyway). Another thing they are good for is very low current operation. With 1mA you can easily see them in a bright room.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

T&E Engineer
01-19-2006, 08:01 AM
A friend of mine told me about this website that sells 1000 red difused LEDs for $10.99. Although they get you in the shipping.

http://www.besthongkong.com/product_info.php?products_id=30

Thanks.

StarMan
01-19-2006, 09:31 AM
I've tried besthongkong and cwithk and I find that there are a lot of duds in their shipments (not a big deal when you just buy the cheap diffused reds and greens).· My personal favorite is hkemart.· They sell online and through ebay.· I buy the 8000mcd whites at $190 per 1000 plus $20 shipping.· It sounds like alot compared to the the other LEDs on this post but just 2 years ago I was buying 1000mcd whites from Lumex·at $1430 per 1000 plus shipping.· The quality from hkemart is excellent and very consistent.

BTW I did a little informal research and submitted a·write-up on the cwithk 4-lead RGB LEDs to this post: http://forums.parallax.com/showthread.php?p=536043

Chris I.

bulkhead
01-19-2006, 01:07 PM
Why are blue led's so much more expensive? Can you tell the brightness of an led by looking at the numbers, or do they not matter?

www.mpja.com has 1400mcd 5mm blue leds for $.49 each, but there's an ebay auction for 5000mcd 5mm blue leds at roughly $.10 each. Why the difference? Isn't 5000mcd brighter than 1400mcd?

Bean
01-19-2006, 04:23 PM
I think it depends on the viewing angle also. The same LED with a narrower viewing angle will have higher mcd. I not positive about that though.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

Newzed
01-19-2006, 08:28 PM
Bean, I really hate to give up on the SMD LEDs.· I have never handled them but I see them on my PDB and other devices.· Would it be "cost effiecient" to solder them to two pins like on a strip header, cut the pins off at the plastic holder, then stick them thru two holes in the map?· I looked at a picture of them and it looks like there is a small notch in each end that might accept a wire.

Since you have zillions of them, would you consider selling me a few so I could play around with different mounting methods?· If the strip header pins would work, that would give me a very consistent platform to start with.

Sid

Newzed
01-19-2006, 08:30 PM
Bean, I forgot to ask - what size resistor do you use with them?

Sid

Bean
01-19-2006, 08:49 PM
Sid,
By "size" to you mean what resistor value ? Or do you mean what size of SMT resistor ?

Send me a PM with you address and I'll send you some. How many will get you started ?

They have a typical voltage drop of 2.0V so if you are running them from 5.0V and you want 20mA (they will handle 30mA) you would use a 150 ohms resistor. For 30mA use a 100 ohm. A 120 ohm will give you 25mA.

Looking at the size, I would try to solder them on to right-angle header pins. That should match up pretty good.

Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

Newzed
01-24-2006, 02:27 AM
Bean, received the LEDs - thanks a lot.

Tried soldering them to a pin header·- that was no good.· Had some breakaway socket pins - long solder tail and machine collets like you plug a DIP into - so I tried that.· The LED fits across the two socket holes perfectly.· Put a dab of solder paste on each end, broke off the two pins and plugged it into my breadboard.· Works great - not very labor intensive, a couple of minutes per LED, and I have a structurally sound SMD LED I can stick thru my map and solder from the backside.· Now all I have to do is find a decent map.

Sid

Bean
01-24-2006, 02:39 AM
Sid,
· Cool, I'll have to remember that if I need to convert any of them myself.
· What do you think about the brightness ? Will they work for you ? If so I will sell you a larger qty.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

Newzed
01-24-2006, 10:27 PM
Bean, the brilliance is unbelievable.· I used a 270 ohm resistor and it is still too bright.· I'll try a 470 and see how that does.

I have to figure out the cost of the socket pin strips and everything and see how it compares with the T1-3/4.· I really like the idea of having the LED mounted on the socket strip with the rigid pins.· That means I can just push it through the map and the foam backup without having to drill any holes.· I have found a map·- 30 x 43 -· which is about the right size.· Now I have to find some 1/4" styrofoam to mount the map on,and I'll probably have to make a frame so I can hang the thing on the wall.· The pins on the socket strip are .430 so they would be long enough.

How much for, let's say, ·130 of the LEDs?

Sid

Bean
01-24-2006, 11:10 PM
Sid,
How are you planning to connect the pin to the rest of the circuit. I only ask because if you solder wires onto them the pins may get hot enough that the LED will come off. I'd love to see a picture when you get it completed. Oh let's say 0.10/each.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for only·$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
·

Newzed
01-24-2006, 11:46 PM
Bean, I got a price on the socket strips from Samtec.· Each pair of pins would cost .28.· That makes the cost per LED .38, compared with .095 for the T1-3/4.· Now I have to decide if pushing the pins in instead of drilling two holes is worth the extra .28 per LED.· I have a feeling it is, but I'll get back to you.

Sid