Hey all,

I know this is very basic, but what would I need to replicate the simple upper and lower saucer lights that were originally on the AMT lighted kits? I guess I'd replace the grain of wheat light bubs with LEDs? I don't know what kind of voltage to supply, if I'd need to wire any resistors... The basic basics here. I appreciate your help.

Thanks,
Rob

"It all depends" is the basic, basic answer ;)

All leds use a certain voltage, most likely in the 2-4v range to fire. Too little and they wont light, or be dim. Too much and they will die or burn too bright, then die.

If you have a wall wart at the voltage size of the led or very close, you most likely wouldn't need resistors and can do it straight up.

Example:
Let's say the led uses 3v. The wall wart you have is 6v. You could use an appropriate resistor, or you could wire two 3v leds together + to - to + to -. 3+3=6. If you had a 5v or 7v wall wart, this should also work ok. The lights might be a little dimmer or brighter.

If you only had a 12v wall wart, then you would need 4, 3v leds to avoid resistors. If you put one 3v led on a 12v source, it will instantly burn out, pop, puff or simply stop.

Two 3v on a 12v would likely burn bright and die very soon, if not immediately. 3, 3v on the 12v, will burn bright and die sooner than they should, if not immediately. If you put 5, 3v on a 12v, then they would likely be dimmer than usual, but will live a long life.

There are other complications too.

I actually just faced the problem last night and the video is uploading to youtube now. Chk my Vader TIE thread here later today. My red leds fired at 2.5v. I was using a 3v source. They worked fine. I ran out of mA (millampers) to light as many as I wanted. I didn't ahve any other 3v wall warts, so I had to switch to a 5v wall wart. This made me string pairs of leds to each other to equal the 5v. Otherwise, they would have burned out on me.

mA is the other factor. The wall wart will usually have hundreds of mA listed next to the voltage output. My first plug was 3v, 300mA. My new one is 5v, 1000mA.

Each led uses volatge to fire and determines intensity. mA determines how many you can use. My red leds needed 75mA each. So my 300mA only covered 4 leds. The new 1000mA means I can run about 15 if I wanted. I only need 6, so there is plenty of overhead. Excess mA will not burn out your leds. But if you exceed your mA rating, then your leds will simply turn off until you reduce the load.

That's about as basic as it gets w/o invoking resistors which are their own beast. I buy mine pre-rated to particular voltages. I have no idea how to do that math myself, so I let the led vendor do it for me.

v and mA are the keys. If you are only putting one or two leds in, don't worry about the mA. Do worry about the v.

As I recall, those were pretty dim grain-o-wheat bulbs. Weren't the lenses green?

What model man said, but here are some specifics if you want green light.

LEDs are bright and have a narrow lighted area. They come in red, yellow, green, white and UV. There are some exotics in other colors. Green LEDs need about 2.3 volts

You can use higher voltage (i.e. 9v) with current limiting resistors. You can also use a higher ohm resister with 3V to reduce (dim) the light output. You can broaden the lit area by making the LED surface opaque through rough sanding. You can also make a small "light box" and use reflected light instead of direct light from the LED.

Here's a diagram with 2 green LEDs running on a 3V source Notice they still need 33 ohm resistors (http://www.radioshack.com/product/index.jsp?productId=2062312) to avoid running them at too high power (higher ohm resistors are ok to dim the light: try 68 ohms (http://www.radioshack.com/product/index.jsp?productId=2062314)). Here's a link to the example LED (http://www.eled.com/product.asp?catalog_name=leds&product_id=e1503gd) I used. This is the wizard (http://led.linear1.org/led.wiz) I used to generate the diagram.

A 3V source could be 2 AA batteries in series (each are 1.5 volts). Consider where you want the power source to go (battery holder?), and where the on/off switch will go.

These very bright blue LED's (http://www.eled.com/product.asp?catalog_name=leds&product_id=e7113pbc-a) might look cool.

Clicking on the PDF spec sheet they need 3.5 v at 20mA so you'd need more than a 3V source. using a 9v source and the handy wizard that comes out to 330 ohm resistors (http://www.radioshack.com/product/index.jsp?productId=2062319) in parallel or 100 ohm resistors (http://www.radioshack.com/product/index.jsp?productId=2062315) in series.

Hint: wiring in series will allow batteries to last longer but if one LED fails they both go out. Series diagram attached. I like 9V because the batteries are a convenient size and the connectors make that cool snappy sound (http://www.radioshack.com/product/index.jsp?productId=2062218).

Hey guys, thanks - when will I learn there's no such thing as a basic answer Diagrams are always helpful though.

The lenses/domes top and bottom of the kit are indeed green, so I wouldn't need color LEDs. Are grain of wheat bulbs still available? Probably not, and why bother eh? I'm thinking I'd just like to use a battery holder with 2 cells, and put in the base. I think the kit I'm getting has the cutout in the back of the base where they were planning to put switch for the Leif Ericson ship

Thanks for the detailed info
Rob

Hey guys, thanks - when will I learn there's no such thing as a basic answer Diagrams are always helpful though.

The lenses/domes top and bottom of the kit are indeed green, so I wouldn't need color LEDs. Are grain of wheat bulbs still available? Probably not, and why bother eh? I'm thinking I'd just like to use a battery holder with 2 cells, and put in the base. I think the kit I'm getting has the cutout in the back of the base where they were planning to put switch for the Leif Ericson ship

Thanks for the detailed info
Rob

Grain of Wheat bulbs are still made and can be purchased through Micro Mart.

However you might want to use warm white leds which will last longer and not generate any heat. The ones I have are out of a Michales Christmas strand and run at 3v. 4 of them run for 18+ hours on 2 AA batteries.

If your going to light the saucer why not go all the way and light the 2 warp engine front caps? The original I had had the saucer and engines lit.

Best bet is to wire using 9v. The batteries are small, connectors simple. (http://www.radioshack.com/product/index.jsp?productId=2062218) Use a 330ohm resistor (http://www.radioshack.com/product/index.jsp?productId=2062319) with each LED and you'll be fine. The advantage is later when you're doing more exotic stuff, 9V is ideal for many devices.

Otherwise get a 3v battery holder (http://www.radioshack.com/product/index.jsp?productId=2062252). White LEDs tend to need more than 3V (unless you go the Michaels route). I'd get run-of-the-mill green leds and stick a resister on each one of them (33 or 68 ohms). You will have to wire them in parallel as 3v isn't enough to do a series circuit.

Get an assortment of LEDs (http://www.radioshack.com/product/index.jsp?productId=2062588) (this won't have any ultra-bright or white LEDs, probably just red green yellow).

Get a breadboard (http://www.radioshack.com/product/index.jsp?productId=2734155) and some jumper wires.
(http://www.radioshack.com/product/index.jsp?productId=2103801)
Get some of the resistors mentioned above. The resistor assortments tend to have too many in the thousand or mega ohm range (useless for LEDs) so get specific resistors. I wire in 9V so I get a bunch of 330ohm resistors (these are good for most LEDs using a 9V source). For 3V you need the 33 or 68 ohm resistors (for green LEDs). You can probably get away with no resistor, but it may shorten the life of the LED and batteries (and may be brighter than you want).

Wire them up using the breadboard so you can see the effect of different resistors on the amount of light output without having to solder them. Here's a simple tutorial on using a breadboard. (http://www.instructables.com/id/Breadboards-for-Beginners/)

Armature wire (http://www.radioshack.com/product/index.jsp?productId=2036277) is a good wire to use to connect components within your model. This stuff is made for electric windings but works fine at the low voltages we use. It has a thin coating of insulating material, just remove it with some sandpaper (or the edge of an exacto). Here's a good beginner soldering set (http://www.radioshack.com/product/index.jsp?productId=2062758). Practice before you start "for real."

Get some switches. These are SPDT (http://www.radioshack.com/product/index.jsp?productId=2062492) (single pole double throw) meaning they are "two way" switches. You can use just one "side" of the switch. It seems to be cheaper than looking for SPST (single pole single throw). The only ones I could find at rat shack were in an assortment of less useful switches (http://www.radioshack.com/product/index.jsp?productId=2062487), or big single switches.

All electronics is a good source of LED (http://www.allelectronics.com/make-a-store/category/340/LEDs/1.html)s and flashy kits (http://www.allelectronics.com/make-a-store/category/305/Kits/1.html) when you want to get more fancy. They even have LEDs that flash on/off (http://www.allelectronics.com/make-a-store/category/340200/LEDs/Flashing/1.html) by themselves or sequence through a range of colors. Actually looking at their site, they seem like a better choice than radio shack for everything. Cheaper too. The only thing I couldn't find there was magnet wire...

All electronics is the source for my top sekrit flying sub nuclear reactor (http://www.allelectronics.com/make-a-store/item/LED-95/FLASHING-RED-GREEN-BLUE-LED/-/1.html).

It's nukular!

Wow,
Thanks for all the links. It looks like I should be able work something out without too much trouble or expense.

I wonder what the wiring was like for the original setup - Would have just been 3v going straight into the bulbs?

I would have liked to put a couple lights in the engines, but the caps in this kit are just opaque white.

Rob

Wow,
Thanks for all the links. It looks like I should be able work something out without too much trouble or expense.

I wonder what the wiring was like for the original setup - Would have just been 3v going straight into the bulbs?

I would have liked to put a couple lights in the engines, but the caps in this kit are just opaque white.

Rob

It was just the 3v to each light. All bulbs had really long wires and you twisted the bare wire together when you attached it at the battery holder, and switch.

The end caps for the engines went from a clear orange to opaque white when the lighting was dropped. The fix was a trip to the market and dropping 20 cents for 2 of the small vending machine toys packed in the clear/colored little pill shaped plastic packs.
Cut the domes off the model part with a razor saw, cut the clear plastic from the toys to fit and then frost the plastic. Glue on and your set.

Guys,
I went to the electronic supply store today, and I ended up getting a couple of maglite replacement bulbs and a little battery holder with a built-in switch. As I said I'm just going for a very basic setup with this particular model. I'm really interested in doing something with LEDs in the future - maybe for my little Polar lights 1701.

Rob

Cool!

If you decide to light the domes you can purchase this set of clear ones in CultTVMan's Hobbyshop store for $4.95:
http://www.culttvmanshop.com/shop/product.php?productid=16307&cat=328&page=1

http://i146.photobucket.com/albums/r259/Trekriffic/Miscellaneous%20Images/clearnacelledomesfor18inchEnt.jpg

Oh dang, I forgot about the clear domes when I ordered the Starfleet assembly manual. I could have combined shipping on the order.

I'm probably going to skip them on this one... but it would be easy to implement...

I'm going for a replica of the original, so I'm probably going to stick with the basic two lights. Those domes will come in handy for a fully lit model in the future though.

Oh dang, I forgot about the clear domes when I ordered the Starfleet assembly manual. I could have combined shipping on the order.

I'm probably going to skip them on this one... but it would be easy to implement...

I'm going for a replica of the original, so I'm probably going to stick with the basic two lights. Those domes will come in handy for a fully lit model in the future though.

I used those domes on the 18" Enterprise I'm working on now. I gave the a good sand with some 800 grit paper to frost them up a bit and I think they look pretty good. You can see how they look at this thread below.

http://www.hobbytalk.com/bbs1/showthread.php?t=248593

Ok,
I wired the maglite bulbs in series to a little AAA battery holder with a built in switch. I think I'll be putting the batteries/switch in the secondary hull as there's enough space. As for turning it on and off - I'm thinking of not gluing in the sensor dish and mount, and just removing it when I need to get at the switch. Not elegant.... but it should work. Haven't thought about how to keep the dish in place without making it permanent yet.

As for the building of the actual kit - It seems like all the build time is going to be spent on sanding seams. They're really bad on the nacelles for starters. Even if you just sand it so the actually joining seam is gone, there's a sort of hump where the two pieces meet. Sand it enough so it's gone, and you're ending up with a sort of flat spot.

Ok,
Haven't thought about how to keep the dish in place without making it permanent yet.

Put one or more magnets on the back side of the sensor/deflector hub/piece and some thin metal around the inner edges of the 2ndary hull opening. You could try the other way around too. That will keep the magnet weight odd the deflector hub and help with weight issues. Mounting the magnets on the rim of the inner hull is easy w/. superglue. It will be strong enough to hold it in place and easy to pull off.

If you were to get complicated, you could rig a push button switch on the back side of the sensor spike and use that as your push button switch. If that makes sense.

PS. Having access to your wiring later is always a good thing!

Happy modeling!

use plastic shims instead of putty so that you can control the amout you sand off.

use plastic shims instead of putty so that you can control the amout you sand off.

Hi, I think I follow, but could you elaborate the method?

Well, I was all set to go ahead with the batteries/switch in the hull, but realized that the sensor mount, even if it's not glued in on this version is held in place by the hull. I'm going with the batteries in the base routine.