Need 120V Tea Lights/LED

[Jim Eller]

I am looking to build some light house type lights using the old power pole glass insulators for the dome.

I need to find some lights about the size of tea light but in 120V. The tea light work fine but it means replacing batteries quite often which would deter use.

Anyone know of a source for 120V LED's that are about an inch or so in diameter? Seeing this is a wood project, heat is a factor.

Thanks.
JimE

[David Bassett]

Jim, I don't know of something exactly like you ask for, but have a couple ideas that might work for you.

I'm not aware of any 120V devices using LEDs that are as compact as you want. But you may be able to get under-cabinet puck lights to work. E.g. Lee Valley had some new ones on their front page a while back.

If that doesn't work and you want to avoid any circuit work and would consider a rechargeable battery, maybe you can hide a small flashlight in the rest of your structure. E.g. a Fenix E01 is about 9/16" in diameter by 2-13/16" and will run a long time on a AAA NiMH battery. (I carry one with my keys.)

If you'll consider it, LEDs are low voltage DC devices themselves and a simple circuit isn't hard. You'd then have a lot more flexibility in size & positioning.

My first thought for power is a USB power supply. They're ubiquious these days, you may have one (or several) laying around. If so, you'll need a connector to tap the power leads, e.g:

http://www.adafruit.com/products/1833

If not, you can get a similar wall-wart with a power plug and connector that is easier to use, e.g:

http://shop.evilmadscientist.com/productsmenu/partsmenu/179

(get with a jack!) Or here is a different source, with an even easier to mount jack:

http://www.adafruit.com/products/276
http://www.adafruit.com/products/610

With a reliable 5V DC into your light house, you need to select an LED and wire it. Since you mention tea lights, I'll assume a 5mm domed LED will work. Further I'll assume warm-white, e.g:

http://shop.evilmadscientist.com/productsmenu/partsmenu/360

You'll also need a resistor to limit the current. This example LED has a Vf of 2.7V & Imax of 30mA, but 20mA is recommended for longer life. So you'll need a to drop 2.3V (5V - 2.7V) at about 20mA. Ohms law for a resistor is simple: I * R = V, or: R = V / I. So in this case, (since 20mA is 0.02A), 2.3V / 0.02A = 115 ohms. The closest standard size I see is 120 ohm, e.g:

http://shop.evilmadscientist.com/productsmenu/partsmenu/234

Of course different LEDs will allow different tints or colors and will have different voltage & current ratings, but that won't change the math only the values.

The last trick is to make sure you wire the longer LED lead to +5V from the supply. The circuit goes power connector to LED to resistor to power-connector. (Resistor can be in positive or ground leg of the circuit.) With the resistor you shouldn't burn up the LED if you get it backwards. If it doesn't light, swap leads and you should be good to go.

Good luck!

[Jim Eller]

WOW! That's a lot on leg work and info David.

I'm looking to give these things away as Christmas gifts(I know, it'searly). I need to keep it simple. Something someone can just plug in thewall.

The puck lights may be an option as for size, but the ones that I saw at thebig box store I thought created a lot of heat. Maybe they weren't LED's.

I really appreciate the help.

JimE

[David Bassett]

Hey this stuff is fun. I'm half listening to the football game and *NOT* working on the kitchen light that's acting up. This is great.

LEDs can be hot, if they're bright enough, but I bet you saw halogen lights. I've never seen LED puck lights as small as you want and without a separate power supply. But that doesn't mean they aren't out there somewhere, they seem possible (if not too bright. More size is needed to disapate heat adequately as you generate more heat.) You've left yourself time for some research.

What I suggested was just one possibility. The links were to hobbyist sites (delightfully weird :-) ) that are a little more user friendly. You'd get a better selection at Digi-Key or another industrial site, but they aren't so hobbyist friendly. I'm not sure what's in your area. If you have a good Radio Shack, (an old school one, not the new cell phone store type,) you can probably get local help. If you have a hacker space, or a HS electronics club, you could probably get help there too.

How much space, at the LED and elsewhere, affects what will fit. How many you plan to make total and if they will be displayed alone or in groups also make a difference.

[Jim Eller]

David,

Here is an idea of what I am trying to do. This is not what I plan for the final piece, it's just my first ever lathe project.

JimE

PS: You are right. They were halogen.

[David Bassett]

Your turning looks great. As far as I'm concerned you've done the hard part.

Judging by the dissembled view in the other thread you have plenty of room in your base for a light. (How do you feel about hollowing? :-) ) It looks like you have a pair of 5mm LEDs in there now. How is the brightness? I was suggesting one, because it would be easy, but your glass is darker than I imagined and you might want to go a different way if you want more light. Depending on how hard you want to work, it looks like you could fit batteries and/or electronics in your base and do almost anything really.

[Rod Sheridan]

I am looking to build some light house type lights using the old power pole glass insulators for the dome.

I need to find some lights about the size of tea light but in 120V. The tea light work fine but it means replacing batteries quite often which would deter use.

Anyone know of a source for 120V LED's that are about an inch or so in diameter? Seeing this is a wood project, heat is a factor.

Thanks.
JimE

Hi Jim, there are LED lamps in candalabra base designed for night light applications.

http://www.homedepot.com/p/Lights-By-Night-0-5-Watt-LED-Replacement-Bulb-2-Pack-11301/203777819?N=5yc1vZbmgy

here's one from Home Depot.................Rod.

[Curt Harms]

Don't you need something else that uses a wall wart (plug-in transformer)?:) I used LEDs-on-a-tape for under cabinet lighting. For a short run I bought a 120 volt AC -> 12 volt DC plug in transformer off da Bay. I think I paid <$4 for mine. For lamps there are all kinds of 12 volt LED lamps for automotive use. You should be able to find something to suit your purpose and budget.

[Jim Eller]

Your turning looks great. As far as I'm concerned you've done the hard part.

Judging by the dissembled view in the other thread you have plenty of room in your base for a light. (How do you feel about hollowing? :-) ) It looks like you have a pair of 5mm LEDs in there now. How is the brightness? I was suggesting one, because it would be easy, but your glass is darker than I imagined and you might want to go a different way if you want more light. Depending on how hard you want to work, it looks like you could fit batteries and/or electronics in your base and do almost anything really.

David,

The brightness is fine for a night light with the dark green thick glass but of course they are battery operated.

Like I said, that base is just something I practiced on for a first turning. My plan is to make the final product look more like a lighthouse.

There will be plenty of room for electronics. I just don't want and heat/fire issues.

Thanks,
JimE

[Jim Eller]

Rod/Curt,

Both of those ideas have some good potential. Thanks.

I don't mind the walwart thing. I'm giving them away. :D

JimE