Can LED's in Gemmy Kaleidoscope Light be replaced?

I'm trying to re-purpose a Gemmy Kaleidoscope Green LED light bought last year for outdoor christmas lighting. Is it possible to replace a couple of the LED's in it and make it a multi-color unit (RGB) instead? Here's what the innards looks like. Not sure where I can get the LED part numbers to look them up. Thanks for any help.

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I decided to buy one of these things, and take it apart.

So, now I know a lot more about it, and I can fill in some of the details that before I could only speculate about.

The little circuit board is a constant-current LED driver, based on the CL1221, made by Chip-Link,

http://www.datasheetspdf.com/pdf/786374/Chiplink/CL1221/1

The data sheet is written in a combination of Chinese and Western script. Thankfully it has pictures, well, actually they're diagrams. Those, plus the equations and stuff, make this data sheet mostly understandable.

By the way, the circuit we see on that circuit board is pretty much the same circuit as seen on page 1 of the data sheet linked above.

The interesting thing about this circuit, and this IC, is that it manages to regulate current without sensing that current directly. I mean the current through the LEDs is current flowing on the secondary side of that little transformer. Yet all the parts capable of sensing and regulating, those are all over on the primary side of the transformer.

Anyway, just to prove that this LED driver really does regulate current, I decided to try it with some loads besides the 3-LEDs-in-series that it came with, while at the same time measuring current through the load and voltage across it.

As you can see from the attached pictures, this little circuit board really does regulate current. Specifically, this board stubbornly holds the current at around 300 mA, over a wide range of different loads. In these pictures, the meter on the left is showing us current, in amperes (A), flowing through the load, and the meter on the right is showing voltage, in volts (V), measured across the load.

Regarding my test load, I attached four 10 ohm resistors in series, for 40 ohms total, and I used a fat clip lead to selectively short 1, 2, or 3, of them, so that I could get 10, 20, 30, or 40 ohms, as desired.

With a constant current of 300 mA, that corresponds to voltage of I*R = 3.0 V, 6.0 V, 9.0 V, 12 V, respectively.

Also power dissipation of ,

I^2*R = 0.9 W, 1.8 W, 2.7 W, 3.6 W, respectively

In the pictures I have shared here, I think I just show the load wired as 40 ohms, in one pic, and 20 ohms in another.

Also I took a picture of this driver board loaded with the three LEDs in series, that came with my Gemmy Kaleidoscope.

The black disc sitting on top of these LEDs is a black plastic cap, formerly from a bottle of cat litter. I think that's where it came from. I found this cap does a good job of attenuating the light from the LEDs, for the purpose of taking a picture.

I mean, enough light gets through to show us the LEDs are turned on, and it also blocks enough light so the camera is not blinded, and the other things in the picture are easy to see.

gemmy-LED-driver-01.jpggemmy-LED-driver-02.jpggemmy-LED-driver-03.jpggemmy-LED-driver-04.jpg
joe_renaud (author) 11 days ago

This thing is slightly more complicated than I thought. Further disassembly yielded a second circuit board with transformer/coil and a couple capacitors. (Photos attached).

The LED'S are all green and the unit operates on 120 VAC.

From what I can tell the wiring of the LED'S is in series and the "board" is a single layer piece of aluminum like Jack suggested. There is a circuit trace all around it that you can just see if you hold it at the right angle under the white coating. The Red lead trace goes to the LED1 "+" terminal, through LED1 then out from the "-" terminal and over to the "+" terminal on LED2 and so forth all the way to Black.

The odd thing in the middle is a shaft from a motor under this board that a plastic wheel rotates on to break up the light and make the kaleidoscope effect.

I would most definitely like to try to change two of the LED'S to see what it might look like. Still not sure what I'm looking for model number-wise but will try Jack's search.

Am not having good luck with getting the current reading from the LED'S as they practically blind you as your trying to get your leads on the terminals. But the tag on the whole unit says .06A, 5.8W. I'm sure part of that rating is from the motor which shows to be 2W. Not sure if any of that helps, but it's been an interesting adventure. Thanks for the responses thus far.

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Hey! I thank you for the pictures, and also for the additional descriptions of what you have discovered.

Now I am wondering: can you resolve the hieroglyphic text printed on that 8-pin IC?

The reason it is relevant is because, if we can find a data sheet for that IC, then that will tell us a great deal about the function of the circuit board to which it is attached.

I am still guessing this circuit board is some kind of constant current driver for LEDs. Or maybe I am hoping this is what it is. You might have noticed this guess is the same as I was guessing before, before seeing a picture of this board. So, this is the same hypothesis as before.

This circuit is kind of mysterious though, in that, assuming it is a constant current regulator, the feedback that makes that regulation happen is, I think, happening on the primary side of that little transformer. So the mechanism by which it is sensing the current flowing in the LEDs, on the secondary side of the little transformer, well, it is a little bit mysterious.

Or it is something I have not seen before, or at least not before today. As of today, I have discovered at least one data sheet for an IC that claims it can sense (and regulate) current to LED lighting in this manner, so I believe such things are possible, but it is kind of something new to me, so I am curious to know what the part number for this particular 8-pin IC in your, Gemmy Kaleidoscope, gadget.

By the way, also on the subject of measuring current, your words,


"Am not having good luck with getting the current reading from the LED'S
as they practically blind you as your trying to get your leads on the
terminals."


these words tell me that you do not know how to measure current.

The reason why is because measuring current in a circuit usually requires breaking that circuit, e.g. by cutting a wire, and inserting the meter in series with the rest of the circuit. Also if the meter is a multimeter, you have to configure it as an ammeter, as a current measuring meter. This is often, but not always, accomplished by unplugging one of the leads and plugging it into a different jack, and turning the dial to the big current (DC current) setting.

Note that measuring current is NOT the same thing as measuring voltage.

And, of course, do not try to measure voltage with your meter set up in ammeter mode, because the meter looks like a short in ammeter mode.

This tutorial, at sciencebuddies.org,

https://www.sciencebuddies.org/science-fair-projec...

shows us how it is done.

I am kind of hoping that link points directly to the heading labeled, "How do I measure current?", under the tab labeled, "Using a multimeter". If it does not, then I guess you kind of have to kind of navigate your way in there, to that heading.

Also, I guess I could draw you a picture myself, or take a picture of my multimeter set up to measure current.

The other thing I was going to mention is clip leads.

https://en.wikipedia.org/wiki/Crocodile_clip

There are ways to temporarily attach wires to things, so your hands are free to move the meter, or the LEDs, e.g. to point the light emitting parts away from your face, so that you are not blinded by this light trying to read the display on the meter.

I humbly suggest you contemplate the operation of the existing circuit; i.e answer the question: How does it work, the way it is, with three green LEDs?

One way to answer that question is by discovering, and drawing, a circuit diagram for the circuit which powers those three green LEDs.

Some things to look for: Are all three LEDs wired in series? Are there any resistors wired in series with any of these LEDs. What is the character of the source supplying current to these LEDs? Is it approximately a constant voltage source, in series with a resistor? Or maybe it is something more complicated, like a constant current source, or something like this?

Anyway, I think once you have an understanding of the way the circuit works, then you will be prepared to modify it to do something slightly different.

Or if you are adventurous, maybe you could try swapping out two of the existing green LEDs, with one red and one blue, and see what happens.

By the way, I do not know who, which manufacturer, made these LEDs, but I think this package (i.e. the shape, size, number of pins) is called,

"2-SMD, gull wing, exposed pad, 0.315 inch (8.00 mm) diameter"


This guess is based on me browsing through a parametric search through a catalog at Digikey.com,

https://www.digikey.com/products/en/optoelectronic...

Although I do not recommend buying your LEDs from Digikey, if you can find them somewhere else, just because Digikey kind of has bad, too high, prices for almost everything they sell.

The do have great selection though, like, everything under the sun, which kind of justifies the parametric search. I mean, their catalog is certainly useful for window shopping; i.e. seeing what is out there, and looking at pictures (and data sheets) of it.

The other thing I was going to mention about this kind of LED, I think it is somewhat high powered, like maybe 1 to 3 watts per LED. So that white plate, underneath the LEDs, is probably made of aluminum, and it acts as a heat sink.

Of course, if you know how to use a multimeter, you can discover the voltage across, and current flowing through, each LED, and power is just those two numbers (voltage and current), multiplied together.

In the event that you replace some of these LEDs, I think you want to make sure there is good thermal contact between the back side of the LED, and that white plate thing. I mean, an air gap would be bad. Ideally, there would be zero space in between the LED and the back plate, with both perfectly (or almost perfectly) flat. Not sure if thermal grease is necessary, but if you already have some, it probably wouldn't hurt.

At first I thought this was a portable unit..

Now I see it has a power cord, so the voltage might be enough to run a self color changer LED...

You know, I had not considered what these look like from the outside.

Guessing you used an image search on the words "gemmy kaleidoscope". When I did this, a lot of the results were images found at walmart.com, so I am going to link to some pages there, actually some searches using walmart.com's search engine, and you can see these search terms as arguments in the URLs below.

Walmart search for "gemmy kaleidoscope lights"
https://www.walmart.com/search/?query=gemmy%20kale...


Simlar product called, "gemmy whirl-a-motion" lights
https://www.walmart.com/search/?query=gemmy%20whir...

All these look similar in shape: vaguely triangle-shaped projector head with power cord coming out the back, gimbal with stake on the bottom, so the projector head can be swiveled up and down.

The colors seem to vary from one model to the next though.

It might be the case they kind of built all of these with the same floor plan.

Also might be the case that these all have the same LED driver. We can imagine a constant current regulator robust enough to drive a series stack of LEDs, whose total voltage drop might be anywhere from 0 to 12 volts. You know, a constant current regulator does not care about the voltage at its output, just as long as that voltage does not exceed some maximum value.

I mean, it would kind of make economic sense to just use one constant current driver, capable of driving any combination of three LEDs in series. That way they could use the same driver circuit for every model they make. I don't know if they actually designed these things that way, but maybe they did.

Final thought: If Walmart is selling these things for like 15 USD each, then they might have us beat on the cost of parts and labor; i.e. the cheapest, easiest, way to get a R-G-B colored, Gemmy Kaleidoscope Light, might be to just buy one from the Walmart.

iceng12 days ago

Do they shine up or through ?

Green suggests not enough voltage to power an RGB self changing LED..

RED or YEL would work..

+1
You can get the same type of LED as fading milticolor LED's, if hard to get just use any with suffient power.

To give you some more context on this LED package, it is a shape I have seen before, in particular at DX.com.

Speaking vaugely about DX, almost all their stuff is made in China, and ships from there too, so it typically takes weeks, to months to arrive at a destination in the FUS (former United States). I am not sure if this best place to buy this style of LED. The direct-from-China eBay sellers probably have these LEDs too, maybe at better prices, but these also take forever to ship to the FUS, unless you can find one that has a warehouse in the FUS, with the particular part you want already in stock.

Regarding the name of this package, DX seems to be using the words, "LED Lamp Bead", to describe this package, but I don't know how common that language is. I am guessing the package is more properly called "gull wing", with a spec for the diameter of the central circle, like 8.0 mm, or whatever is most common.


Anyway, here are the links into DX's pages, current at the time of this writing:


1W red, 10 pieces
http://www.dx.com/p/625nm-1w-40lm-red-led-light-bu...


1W blue, 10 pieces
http://www.dx.com/p/455nm-1w-25lm-blue-led-light-b...

1W green, 10 pieces
http://www.dx.com/p/530nm-1w-60lm-green-led-light-...

plant growth combo, 4 red + 1 blue
http://www.dx.com/p/jr-3w-plant-grow-red-green-lig...

By the way, these LEDs want a heatsink, when driven at full power, which is around, (3 volts)*(350 mA) = 1050 mW = 1 W. Actually, he forward voltage is usually different for different for different colors of LED, but probably knew that already just from reading the Wikipedia article for LED. I wonder if that article mentions the name for this particular package style? Um... no. I don't think so, but they have a picture of some of them, with little star-shaped heatsinks, in the section titled "High-power", here:

https://en.wikipedia.org/wiki/Light-emitting_diode...


DX also sells the little, flat, star-shaped, heatsinks, for this kind of LED, here:
http://www.dx.com/p/20-x-20mm-led-aluminum-heatsin...

Also some places will sell you this kind of LED, with the star-shaped heatsink included, and attached,... I mean, already soldered together. I know this because I have bought them that way before.