Great Deal on Green LED's

[thedudedrummer]

Hi, I was planning on going for a different spin on the standard LEDtrix choice of red, and go with green for my halloween display. I found a decent set for a good price on ebay at http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320251698263 and I was just wondering if they would fall into spec for those that work with the LEDtriks boards. Im a "noob" on these forums, so please escuse my ignorance, I just have not found a standardized set of data for what LED's to use or not to use. I was also thinking orange, but I was unable to find any with a decent light output for a reasonable price (since I will be making a 1x2 board with smaller spacing for halloween.. probably 1/3"... and a 3/4" version with red LED's for christmas).
Thanks, Mike

Specs are
- Size: 5mm
- Emitted Colour: Green
- Lens Type : Water Clear
- Forward Voltage: 3.2-3.4V
- Reverse Current: <=30 uA
- Peak Wave Length: 465-470nm
- Luminous Intensity Typ IV: 11000-13000 mcd
- Life Rating: 100,000 Hours
- Viewing Angle: 25-30 Degree
- Operating Temperature Range: -25℃-+85℃
- Preservative Temperature Range: -30℃-+100℃

[thedudedrummer]

Here were the possible orange LED's
http://cgi.ebay.com/100x-Orange-5mm-LED-5000mcd-Lamp-Light-Free-Resistors_W0QQitemZ300224990045QQihZ020QQcategoryZ 66954QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Emitted Colour : Orange

Size (mm) : 5mm

Lens Colour : Water Clear

Peak Wave Length (nm) : 610 ~ 620

Forward Voltage (V) : 1.8 ~ 2.2

Reverse Current (uA) : <= 30

Luminous Intensity Typ Iv (mcd) : 4000(Typical) ~ 5000(Max)

Life Rating : 100,000 Hours

Viewing Angle : 20 Degree

Absolute Maximum Ratings ( Ta = 25°C )

Max Power Dissipation : 80 mw

Max Continuous Forward Current : 30 mA

Max Peak Forward Current : 75 mA

Reverse Voltage : 5 ~ 6 V

[shocker]

ok has for the green the Forward Voltage is to high and Luminous Intensity Typ IV: 11000-13000 mcd is to high too,
but the orange one the Forward Voltage (V) : 1.8 ~ 2.2 is perfect and the Luminous Intensity Typ Iv (mcd) : 4000(Typical) ~ 5000(Max) seam to be around what we use,

[thedudedrummer]

Orange it is lol Thanks!

[RJ]

ok has for the green the Forward Voltage is to high and Luminous Intensity Typ IV: 11000-13000 mcd is to high too,
but the orange one the Forward Voltage (V) : 1.8 ~ 2.2 is perfect and the Luminous Intensity Typ Iv (mcd) : 4000(Typical) ~ 5000(Max) seam to be around what we use,

And why is this to high? Green Leds run higher voltage but the Ledtriks contollers is current limited not voltage limited. As long as your required voltage is not too close to 5 volts (> 4 v maybe) it will not matter. The current capacity of the LED is what is an issue. As far as brightness I don't think anyone has had one that was too bright yet. If so you can change out the current reference resistors to drop the current and make it dimmer.

RJ

[thedudedrummer]

Ummmm.... how would I do said action?

[RJ]

If the Ledtriks was too bright after you built it you would replace the three resistors to dim it some. But I doubt there is much chance you will want to do that.

RJ

[P. Short]

The three 1K resistors on the LEDtriks controller board (R1, R2, R3) program the current limits for the MBI5027 chips This assumes that the anode drivers have enough drive. With 1K resistors the MBI5027 chips should current limit at about 18 mA. Higher values of these resistors result in a lower current limit, so if things are too bright you might change the resistors to a slightly higher value (2K would result in about 9mA, 1.5K about 12mA, etc).

With non-MBI chips you should check the data sheets and see how the curves vary (probably not by much).

[thedudedrummer]

*brain hurts* ... ok so If I were to go with the green LED's would I have to opt for a different power supply? If so, what would you reccomend?

[P. Short]

I wouldn't change a thing in the controller or the power supply.

[thedudedrummer]

what would be a good power supply to use? External to the computer...

[omzig]

This is going a bit off topic for this thread, but I, as well as a few other here, are using these: http://cgi.ebay.com/SWITCHING-POWER-SUPPLY-5V-6A-12V-3-6A-12V-0-5A-EMU_W0QQitemZ190219256068QQihZ009QQcategoryZ58288Q QtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

It is a great deal.

[WWNF911]

(audible in the distance) CHA CHING

[thedudedrummer]

hahaha thanks