Introduction: CCCP (Christmas Color Change Ping-pong) Lights

Picture of CCCP (Christmas Color Change Ping-pong) Lights

Here is an idea for a nice string of Christmas lights.

It is made by bright ping pong balls slowly changing their color through the sequence RED, GREEN, BLUE, YELLOW, CYAN, PURPLE, WHITE and again ...



At first all balls change color at the same time, but due to the less than perfect LED chip internal clock, after some minutes each led has its color different from the others !

Step 1: Parts and Materials

Picture of Parts and Materials

You need tese parts and materials:

- slow flash color LEDs (browse ebay with these keywords), I used 30 of 5mm type

- white plain ping pong balls (you can find the by dozen on ebay or just on your street stores)

- a simple pvc insulated bipolar copper cable (I used a white one, but choose every color you want)

- a wall wart power supply (I used a 12V/1000mA one, but every type from 7V upto 13V works)

- an LM317 regulator IC (a 7805 type can be used, but in other way, see next steps)

- a 2.2 ohm 1.5W resistor (or a parallel of higher value resistor group, see next steps)

- a 1000uF/16V electrolytic capacitor (470uF or 2200uF work as well)

- heat shrinking tubing (2-3 mm type)

- clear hot glue (with the relevant gun of course)

- moderate power soldering iron

- typical christmas plastic fake green festoons (optional)

Step 2: Prepare the Balls

Picture of Prepare the Balls

Make an hole on every ball. I suggest to punch them on one of their "poles" (north or south) if you consider as equator the circonference you can see around them. Some time there is a logo on one pole, so for best results punch this pole with the hot tip of your solder iron (plastic smell so bad, don't inhale!) to hide the logo from the final view.
Take care the hole be smaller than a led, it have to be pushed inside with some resistance.

Step 3: Prepare the LEDs

Picture of Prepare the LEDs

Use the hot gun to put a small amount of glue on top of every led: when it cool helps to diffuse the coloured light all around avoiding hot light spots on ball surface.
Take care the glue "blob" is smaller than led's diameter so it can fit the ball hole.

Step 4: LEDs Into the Balls (ouch!)

Picture of LEDs Into the Balls (ouch!)

1) Gentle push every glued led into a punched ball then glue them together (use hot glue).

2) Cut short pieces of 3mm hot shrink tubing. The have to be 3-4mm shorter than the shorter led terminal (cathode "-") to allow soldering.

3) Insert hot shrink tubing pieces on both led's terminals, then bend with pliers the residual exposed lenght of both terminal at right angle, I suggest in opposite way.

4) Finally take care to pre-tin the bended part of terminals to easy the soldering on next steps. Tubing can start to shrink with solder heat but it is not a problem.

Maybe better insert the insulating tubing BEFORE hot gluing the led, so the glue can secure and seal the tubing itself. In some cases I did it this way, see next steps photo.

Step 5: Prepare the Wire

Picture of Prepare the Wire

1) Use a permanent marker or so to mark the wire at regular steps, say 30 cm (1 foot).
It is a good idea to mark the same side of bipolar wire on every step so you can know the polarity when you'll solder the leds (they are polarized, have a + and - terminals, invert them and led is "fried")

2) Using a cutter, cut away a small amount of insulating pvc on both side of the bipolar wire to expose a 2-3 mm of nude copper

3) using the solder iron and electronics tin solder wire, tin the exposed copper wire on both sides of the bipolar wire

Step 6: Solder LEDs to the Wire

Picture of Solder LEDs to the Wire

I believe this is the hard part of this instructable. You have to be confident with soldering wires and electronic components to avoid led's frying, short circuits and other bad results.

You have to deal between fast action and good solder, since LEDs don't love too much heating their terminals and even PVC insulating tends to melt easily and retire from heated copper, you can make short circuits between the + and - wires !

All in all the major trouble is the PVC melting, since LEDs terminal are long enough to avoid excessive heating.

But push away your fear and let's go !

Face the bended part of LED's terminals to the tinned copper wire and solder them together.
Since you have pre-tinned both parts, it would be relatively easy and you don't need a third hand to get more tin solder wire there !

Repeat for each ball, examine every joint for short circuits or fake soldering, heat the tubing to shrink them to the minimum diameter (it would be 1 mm or so), then hot glue each joint to insulate them from environment. If necessary hot glue the ball side of tubing to seal them.

Finally solder the electrolytic capacitor at the wire ends, respecting polarity of course.
A hot glue touch over its soldered terminals helps to seal them from moisture or so.

Step 7: Make the Power Supply

Picture of Make the Power Supply

Mount the current regulator using the LM317 in the constant current mode, see schematic.

The formulas from datasheet say current I (ampere) = 1.25 (volt) / R (ohm).

I supply 20mA (0.02 A) to each led, so total current has to be 30 x 20 = 600 mA (0.6 A).

This lead to a 2.083 ohm resistor. I used a 2.2 ohm standard value one.

This piece has to dissipate almost P (watt) = V x I = 1.25 * 0.6 = 0.75 watt, so I used a 1.5 watt resistor to avoid overheating.

You can also put on parallel a lot of higher value resistor to obtain the right value:
- 7 x 15 ohm resistors
- (9 or 10) x 22 ohm resistors
- 13 x 27 ohm resistors
- 16 x 33 ohm resistors ... and so on, but remember you have to enclose all these part in a small housing.
Thus these resistors can share the dissipation in equal parts, so they can be 1/4W type.

I soldered components each to other by their terminals, insulate where needed and put all inside a small plastic container I found in an easter egg. Two holes on the opposite sides allow wire from wall wart and to LEDs string to enter the small egg (a tight knot on both wires ensures circuit safety from external pulls). Please double check the circuit to avoid short circuits, otherwise all LEDs can be fried !

With a 12V wallwart all circuit doesn't overheat so much, even inside the plastic housing, but avoid to wrap all internal circuit in electric tape.

So this is a Constant Current power supply, but what if I would use a costant voltage one ?
I say that it would works as well, but until now I don't tried to use it with this circuit, so I can't assure there are no problems with it.
This CC type have been worked well from 2 years now, without any problem.
Maybe I decided to use it cause at that time I didn't know well these color changing led (eg. which voltage they need), or I thinked at first to make a standard led string and want to save a lot of resistors, I don't remember ...

If you want use a standard 7805 Voltage regulator, you can build a simple circuit just like the Candle Moodlight.

Step 8: Fire !

Picture of Fire !

Ok, check a last time everything before insert plug, close your eyes and ...
voil� you have your own CCCP (Color Changing Ping -pong) lights !

My light string was installed outdoor without problems, due to the tight seal of hot glue, but I suggest to use indoor if you are no sure about it.

Merry Christmas !

Step 9: Variations ...

Picture of Variations ...
After some days, as anticipated in main page comments, I tried this variation: FAST flash color LEDs and little PLASTIC BOTTLES (from yoghurt drink).

Accurately wash bottles inside to avoid "mold" and definitely light dimming.
Punch caps with hot solder iron tip and enlarge hole if needed to allow LED
inserting (it must be TIGHT), then hot glue LED on top first, then on the
bottom (internal) pour hot glue to secure LED and have a diffusing layer.
After cooling a while, close caps on the bottles (well, indeed bottles are
screwed into the caps).

Remember the hot shrinking tubing for insulate and solder LEDs terminals as said before.

A 7805 voltage regulator with classic wiring was used successfully.


Comments

Erind (author)2008-12-05

Anybody know what to look for when trying to find these LEDs on digikey or mouser?

raykholo (author)Erind2009-02-16

not good suppliers for larger quantities.. try bulk sites like goldmine elec or they even have some good deals on dealextreme.com for leds

amaze1 (author)Erind2008-12-09

It seems they are exclusively noname stuff from Far East and China

Erind (author)amaze12008-12-09

I did find SOME LED's from Mouser, but they only seemed to be 3-color color changing instead of full spectrum. They matched the definition you posted very well, but it also specified they were RGB.

amaze1 (author)2008-12-10

Buy these http://www.dealextreme.com/details.dx/sku.6488
add ping-pong balls, hot glue on LEDs, a 5V/600mA or so power supply and you are on the way !
BTW IMHO dealextreme serves very well.

PS: you can use battery box for many other projects

sing1ejack (author)2008-12-06

I'd love to put together a set of LED christmas lights to keep energy usage down and these look georgious - very nice effect. How much did the materials cost you?

amaze1 (author)sing1ejack2008-12-07

I really don't remember exactly (I made it before 2006 christmas), but not so much since I used some recycled elements like the power supply. Other parts are relatively cheap, look on ebay for LEDs, hot shrink tubing, ping-pong balls, you can use them for other projects too. BTW I measured power consumption and it is about 6W. I think you could have better results with a (now) common and cheap USB out (5V) power supply/charger (look for a 1000mA one), and saving the LM317.

static (author)2008-12-05

Just the thing for those Christmas globe Coke bottles. I guess I'll pick up a few more the next time I'm in WM. Though a buck for a 12oz. bottle of Cake is hard to swallow.

oakironworker (author)2008-11-29

I bought some of these off ebay and they just stay red. I waited ten minutes and nothing Do yours start to change right away

amaze1 (author)oakironworker2008-11-30

Strange behaviour indeed, LEDs I bought start changing immediately.
Do you have check voltage ? I use to apply straight 5V, even if sometimes it is too much (depends by color changing leds manifacturer). Maybe you use too low or high voltages.
Try a well kown 12V supply with a limiting resistor (470 ohm).

Vertigo666 (author)2008-11-29

Haha, I read CCCP and said, Soviet lights? But in all seriousness, good instuctable.

amaze1 (author)Vertigo6662008-11-29

Yes, hope soviet friends don't feel offended by my words. I admit, it was a "marketing" trick :)

Vertigo666 (author)amaze12008-11-29

Haha "In Soviet Russia, lightbulb changes you!"

jongscx (author)2008-11-28

...I didn't see mention of an arduino or conductive thread... ... is this one complete? JK, good job!!

amaze1 (author)jongscx2008-11-29

This piece of hardware works without a microcontroller, the LEDs themselves change their color in automatic fashion. Nor conductive thread is necessary here

jongscx (author)amaze12008-11-29

I know amaze, I was kidding. I was commenting on the great simplicity of this project, using a discrete color-changing LEDS, instead of all the other LED-based instructables that had everything that I listed above. :-D

amaze1 (author)jongscx2008-11-29
oh, well ... sorry, I didn't saw any smiley so replied in serious way.
Indeed I have all one needs to develop with PIC, AVR, ARM etc, but I lack on free time, so I end always to make very simple things just like this.
BTW I think this year to make this variation (sorry for neck pain, I don't know how to rotate a video :) ):

Plasmana (author)2008-11-29

That is a very good instructable! I am going to try get the LED's...

Plasmana (author)Plasmana2008-11-29

Oh, and 5 stars!

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