LED Circuits

[Wingnut31]

Is there an easy guid to set up an LED circuit for an plane. I want to light the wing, fuse and tail. I'm guessing I would need 12 in the wing, 6 in the tail, and 6 in the fuse. I would like to keep it as simple as I can. Also, what is ment by the viewable angle of an LED and how does it apply to RC use/ They would be placed inside the plane to light up the skin. The material will be white depron.

[Malc C]

The viewing angle is angle is the angle at which maximum brightness is seen. A greater angle means its viewable from a wider field, a narrow angle creates a spotlight effect.

As for connecting them, typically each LED runs at 2v (unless you buy 5v or 12v versions) and also draws around 20mA, so depending on what power supply you are going to use, you will need a dropper resistor of between 100R and 1K as a rough guide. Also 24 LEDs in parallel will draw around half an amp, so you would be best to use a standalone battery for powering the LEDs (PP3 or 4 x AA would be OK)

[Wingnut31]

Thanks Malc. That helps a bunch. I went to Radio Shack today and found some LEDs but they were about 5 bucks. Heck I can get an LAD Flashlight and take three leds and still have anough for a soda. I found one that has a clip for a hat or pocket and a flexable cable so you can position the light as you want it. It also has a Laser pointer on it too. I thought obout using the laser to point downward to mark the ground under the plane; that way I could judge my height when landing. At 2.99 I bought two, one to disect and one for my tackle box.

As far as the power source what do you mean by PP3?

THX Brian

[rmteo]

A PP3 is the common rectangular 9V battery. Are you looking for white LED's?

[Julez]

Do yourself a favour and get cheap superflux (http://search.stores.ebay.de/HKJE-Led-Lamp-Center_superflux_W0QQfciZQ2d1QQfclZ4QQfsnZHKJEQ20L edQ20LampQ20CenterQQfsooZ1QQfsopZ1QQfsubZ16QQftsZ2 QQsaselZ197621527QQsofpZ0) LEDs from China.
Example. (http://cgi.ebay.de/50X-Mege-Bright-Superflux-5mm-Bianco-22000-mcdFree-R_W0QQitemZ250171747817QQihZ015QQcategoryZ128660QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem)
They are about 30ct each.
Spiderflux LEDs have two advantages: The viewing angle is large, so you can see it better when it is not pointed at you precisely.
You get more bang for the buck, as this type of LED contains more metal, which works as a heatsink for the die, so they are more efficient compared to the standard 5mm type.

Find out the voltage your LED needs, it ranges from about 2V for red to 3.4V for blue/white.
20mA is correct. Now find a resistor that burns the excess voltage at the given current.

Lets say, you have 5V power source, a 2V diode at 20mA.

R=(5V-2V)/0,02A= 150ohm

Better: put 2 LEDs in series:

R= (5V-2*2V)/0,02A=50ohm

Ok?

Cheers,

Julez

[Malc C]

:eek: At over nine euro each it will set him back over 220 euro (or $300 US) juts to light the plane !!!!

Brian, if you are simply looking at making the plane "glow" in the dark like the goodyear blimp, then you might be better off looking at good old fashion bulbs as they will have a 360 degree viewing angle. The downside is they will draw typically ten times the current.

LEDs are starting to make an impact in the auto trade, and it might be worth looking at some of the LED replacement "bulbs" such as the one below

http://www.ultraleds.co.uk/images/ba9wwa.jpg

This has six wide angle LEDs but still only draws 20mA - yes at £3.50 each ($7) its almost as expensive as the one Julez suggested, but you would only need one in each wing and one in the body. Whilst they are available in the UK from Ultra LEDs (http://www.ultraleds.co.uk/uba96ww-leds-white-bulb-wide-angle-volt-p-1014.html?osCsid=1339c5964afb35ba18bf7c6bf26c639a) I'm sure you could find them cheaper from a similar supplier in the US. - try some of the custom car shops if you get stuck

[mem]

Malc, that’s just over 30 cents US each shipped! 9 euro plus shipping for fifty pieces Here is a US link (http://cgi.ebay.com/New-50X-Superflux-White-5mm-R-H-LED-Lamp-22-000mcd-F-R_W0QQitemZ250171756340QQihZ015QQcategoryZ66952QQs sPageNameZWDVWQQrdZ1QQcmdZViewItem) for the same parts.

I agree with Julez that Superflux is the way to go, I use them in low voltage alarms in all my helicopters and they work really well outdoors.

[Malc C]

I wasn't fully awake when I read that post :) - I was thinking that was each !!

[Wingnut31]

Thanks guys. I think EBAY is the best way to go. I was at the store today and found an LED glow stick; someone here posted a thread about them. I was forced to buy it cause I dropped it. Now I have a prewired light arangement to play with till I order some LEDs.


Thanks for the help.
Brian

[mem]

Brian, Good luck with the project.

BTW, you may want to consider getting something like this (http://www.dealextreme.com/details.dx/sku.3863). They look like pre-wired arrays of superflux lEDs. DealExtreme has them in various configurations as well as hundreds of other kinds of LED devices.