Will these LEDs work? They cheap and worth trying out different color
ideas at this cost.

http://cgi.ebay.com/100-LEDs-in-RED-or-YELLOW-5mm-super-brights_W0QQitemZ270153798635QQihZ017QQcategoryZ26207QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


Brand new RED or YELLOW LEDs.

Characteristic 5mm:                  RED                   YELLOW

- Forward Voltage:                 1.8 - 2.2 Volts        1.8 - 2.1 Volt
- Forward Current (max.):        30 mA                         30mA
- Lifetime:                         100,000 Hours         100,000 Hours
- Viewing Angle:                         20 Degree                 20
Degree
- Typical Wave Length:            660 nm                      590 nm
- Luminous Intensity:               2500 mcd                 3000 mcd

Jack-
they should be fine.  looks like the original thread on LED selection 
was blown away, if I remember right, as long as the Vd of the LED was 
under 2.8V they'll work fine.

remember to get 70 instead of 64 in case you blow or lose a few.

I got 100 red ones for $6.99!!!  I want to try Red LEDS, and a black 
face plate!!

I found the requirements!!! Shit, I bought 5mm, I will have to make some
kind of cool light, or some cool lighting in my car!!!

damn, sorry I missed that...

i got my leds on ebay. its a crap shoot but hell its a cheap crap shoot… 
if they're wrong buy more somewhere else. for the price its worth a try.

I ordered mine from that ebay seller - shipped pretty fast - I got 100 
red and 100 yellow - decisions, decisions...

I bought my blue LEDs from this web site: 
http://www.rjmods.com/product_info.php?products_id=69
 I'm hoping these will suffice. The typical Vf is 3.2 so I think these 
should be safe. I foresee a pretty blue keypad in my future....

what is the technical reason that for example blue LEDs are like 5x more 
expensive (Jameco)

??

they're higher in frequency in the light band.

take an electron, it 'orbits' (err exists in a probability cloud, but 
basically orbits) around a nucleus.

excite the electron so it goes into an orbit further from the nucleus (a 
higher energy state).

then let the electron return to its original energy state.  as this 
happens the electron releases energy in the form of light, that energy 
is proportional to the to the frequency of light emitted.

blue is higher in frequency so you have to excite it to a higher energy 
orbit.


lasers work exactly the same way, btw.

sent you a message but I will ask here too -

wasn't there some method to dim LED's on the board?  I am having trouble 
finding ones as low as what i've got now (550mcd)

you can change the resistor value on the logic board to a large value. 
the included resistor is 10k i think, try 15k and 20k (don't solder them 
in, just bend the leads).

the resistor controls how much current goes through the LEDs, hence the 
brightness...

excellent

I will play with that when the new kit arrives

I buy all my LED's from http://myworld.ebay.com/jeledhk

just follow the voltage requirements from what the guys here on the site 
say and u will be ok. I am using some insanely bright blue ones i bought 
from him right now and work great ill post pics soon.

I am actually tempted to get some red ones for a larger version :)

I ended up using a 22k resistor.  I also tried a 47k but it did seem 
just a little too dim.

Surprisingly not a real huge difference from 10k to 47k, much less than 
I expected

oh, and bought the LED's on eBay ;)