Modified LED Tea Light

About: Working on building a startup company in Upstate N.Y. Idea is crafted obsolete-proof electronics, a sort of blend between art and science. We do repairs and services in all things electronics, as we develop ...

Hello Everyone!

LED tea lights are a product out there quite easily found, and so I thought I might share with you how to make these even better-something with your own unique twist!

Although I do provide extra detail in my explanations, making it seem maybe complicated...its a pretty straightforward process: we're basically taking an LED and flame from a tealight candle and replacing it with a little figurine that lights up.

This will require that you know how to make acrylic pieces from molds. If not, I'll provide a link to help you find out how, and though there is a small learning curve, it's pretty easy to learn how to make basic small figures and a very rewarding experience!

Before we get started, we'll have to make a list of parts, supplies, and tools and go shopping!

Parts:

  • 1 or more LED tealight candles
  • 1 or more LEDs (here, I'm using 3mm slow color change LEDs)
  • Some conductive wire (in this guide I'll use 20 gauge solid core copper wire)

Supplies:

  • Some hot glue (or other glue, if you prefer)
  • Solder (and rosin- if that's your thing)
  • Two-part resin mix kit (found in most craft stores)
  • Two-part mold making kit (also found in most craft stores)
  • There are some supplies people use in making these molds, but they vary and are generally inexpensive

Tools:

  • Pliers
  • "Nipper cutters" for cutting wire after soldering
  • Soldering iron
  • Hot glue gun
  • A "Third-hand tool" helps but is optional

Step 1: Disassembly

Taking it apart:

  • Battery cover (held by screw on some versions)
  • Battery
  • Prying off entire bottom part(they usually just pop apart easily)
  • Unbend and pull out negative lead of LED (carefully, so as to save it for another project)
  • Clamp or tape down bottom portion if the LED is soldered to switch (some are instead screwed down, in a different fashion)
  • Pliers in one hand, soldering iron in another, heat up the solder and pull free the LED

Now we have a spot for our own wiring to fit.

Step 2: Fitting

So we have a figurine with wires coming straight out and it's tested with a battery as working.

There's usually a flexible plastic "flame" which pops right off. I like to save these for other projects.

Slide both wires down through the hole from the top and try to gauge how much plastic needs to be removed in order to fit the figurine flush to the top.

Here, I'm using a razor blade. The plastic on these candles is pretty easy to cut. Best to use gloves and a safety cutter or even better, sometimes, I like to use a rotary tool, gloves, and safety glasses with good ventilation...but that too is just my style.

Anyways, try to make it fit with the minimum amount of cutting and it might just set in there, nice and snug.

Good idea to carefully shave off any excess resin at the bottom of the figure, and maybe generally do some cleaning and some final touch ups.

Once you're satisfied with the fit, a drop or two of hot glue helps hold it in place and helps protect those LEDs from possible breakage due to any later bending of the wires.

We are nearly there!

Step 3: Model Creation

Making simple molds is a fairly easy process, once you get a little experience. I was really glad to have come across the class here on instructables and I highly recommend giving that a try if you have not already:

https://www.instructables.com/class/Mold-Making-Casting-Class/

Very basically

  • use a figurine (purchased, or better yet, created with 3d printer or maybe with clay)
  • to make a mold (maybe of a latex rubber mold making kit)
  • And pour in a resin, which hardens and cures inside the mold (I use the two-part mixture that goes 1:1 because it does not have those toxic fumes of the kind of polyeurathane resin that comes in cans)

Before the resin cures, I put in two 3mm (size) slow color-changing (type) LEDs, twisted positive to positive, negative to negative ("in parallel"). Having two allows for a greater variation of colors and has a good level of brightness.

From there, you'll need some kind of conductive wire that solders well. I'm using here a 20 gauge copper wire I picked up locally at a craft store. The slightly larger gauge I'm using is good, because it makes good contact with the battery later.

Snip 2 or 3 inch lengths of wire (or roughly, 5-7.5 cm if you prefer), and give it a little bend near the tip.

If you made you figurines with LEDs like I do, some of the resin may have coated your leads coming from the figurine. This chips off pretty easily, with pliers perhaps, but do take care not to bend those leads too many times, as it might damage the LEDs beyond usability.

Give the leads a little twist close to the figure (keeping seperate the positives and negatives) and test with the battery that usually comes with the candle to see if your figurine lights up.

With pliers, clamp on each copper wire enough to hold it temporarily. Then dab on some hot solder. That, too, is just my style as well.

Snip the excess wire to clean it up a bit.
Straighten the wire to point downwards
Test lights again with the battery.

Step 4: Final Assembly

What we need to now accomplish is to complete the circuit. Power is coming in from the positive side of the battery, into both LEDs simulaneously, out to the switch and back into negative side of the battery.

That's how I like to think about it, anyways.

So to do this:

  • Solder in the positive wire to the switch. (Make doubly sure you have the right wire of the two!). There might be some solder still on the switch blocking the hole, like it is in my case. I just heat it up with my soldering iron and let gravity help me slide the wire through before the solder cools and hardens back up. A little bit more solder helps secure it in place.
  • Slighly bend the negative wire in two places, away from the positive wire. This is to control where it will bend, when later popping things together.
  • Thread negative wire in through center hole (this is another good reason for a solid core wire, as other wires might be more challenging to thread down into the battery compartment)
  • Should be able to gently push bottom part into top part. While doing this, the positive wire is bending a bit more, so hopefully those first two bends will help control where it ends up in there (as long as its not touching the other wire and won't in a million years, we are golden)
  • The bottom and top should pop together flush, and stay together. (If not, it may be the wire, or maybe some glue or debris got in the seams)
  • Bending the negative wire inside the battery holder area helps slightly in securing the two pieces in place and allows room for the battery. One bend is good enough and when putting on the battery cover, the battery is then held firmly. Too thick of wire or layers of bends will keep the battery door from clicking closed.


If all goes well, hitting the "on" switch should light up your very own modified tealight candle!

Step 5:

Some considerations, that will help in assuring good results:

  • though it's a simple circuit, each step of the way the wires can break inside the LEDs themselves, so take care to not bend too close to the led too many times. A dab of hot glue (like in step 3) helps in the reinforcement.
  • too much heat can burn out an led, so crimping the copper wire helps...a quick solder point keeps it in place a bit better.
  • Checking LEDs each step of the way with a battery will help later to zone in on where things went wrong if they happen to.


Possible circuit variations:

  • Can use different types of LEDs..there are different types of colors, and even different colors of candle flicker LED out there, as well as fast changing LEDs which pulse and change rapidly between colors. There are also many sizes of SMD led which are very small, but can be soldered to wire and copper tape among other conductive materials, if done very carefully. Just consider that different types or color of led at the same time can cause it to not work. I have had some success in putting a candle flicker LED in series with other colors, but that requires more battery power in most cases, or might be too dim with only a single battery in others.
  • Can instead of using a battery, wire in to a micro USB port, like the one pictured here, and have it run off a phone charger, portable battery pack, OTG cable (which would make it a sort of phone peripheral)...can even have it running off the guts of a solar powered garden light if you were feeling ambitious...just make sure to add a resistor in line to compensate for the extra voltage difference.

Artistic alternatives:

  • Can paint the shell of the light after the initial disassembly, or even wire an led inside there for extra effect.
  • Can add a bit of something (possibly the plastic "flame"?) around the led before the resin cures, to make the light more diffused throughout the figure. One thing I usually do is snip off the top of the led in the first place, which flattens the top, making the light widen rather than focused. Can buy LEDs with flat tops as well. These as I've shown them will light up walls and ceilings with nice effects because of the shapes on the surface of the figurines.
  • As far as the acrylic figure goes, I've also played around with mixing dyes into the resin before pouring into the mold. Also alternatively created a kind of a colored resin tint and painted the figure after that first time it's hardened and cured. Among other possibile additives are glitters, opalizing powders, and/or different types of paint which lead to different results in different ratios.
  • I've considered making the figure hollow, and there are a few ways of doing this. I just like having a little weight to it. Maybe the hollowness would lend to different types of light diffusion...

I hope that if you're able to make something like these, this guide might have helped. I will love to hear back from anyone with ideas or questions!

Above all, be safe and have fun!

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