# Tea light terror!



## corey872 (Jan 10, 2010)

Just thought I'd take a few minutes to document building some Special High Intensity Tealights (SHI...well, you get the idea.)

I'm building a 4-way horizontal-firing $HIT to run in my landscape lights. This is using a 'Type 2' flickering LED, the venerable 2N2222 transistor and some 8mm warm white 'straw hat' LED's rated for 90,000mcd in a ~140º beam. These provide a soft glow in a color which truly resembles candle-light...not too amber and not too white. Also note, this is 'technically' incorrect. I'm using one resistor to knock the power down from a 5V supply to ~3.5V which keeps the LED's happy. Proper technique would be to have a resistor for each LED. But these seem to live quite happily - and each 8mm LED is technically 5 individual LED dies in one package anyway. Plus they are all flickering at exactly the same rate...if they were flickering at different rates, each LED would definitely need a resistor.

So to start out with, I made a few depressions in a blob of modeling clay to hold the parts for soldering:










Insert four of the 8mm LEDs making sure all the + terminals are up (or all down - doesn't matter at this point as long as they are all the same) and solder.










Pull the array out of the clay, flip over and solder the bottom terminals together.










Set that aside to cool off a bit and prepare the driver circuit. Insert the flicker LED with the '-' terminal bent at a 90º angle toward the transistor and insert the 2N2222 with the base terminal bent 90º toward the LED and solder.










Pull the LED-transistor driver out of the clay, insert it in one of the openings of the main LED assembly and solder the + of the driver LED to the + of the main LEDs.

(from the side)









5 images max, so to be continued.....


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## corey872 (Jan 10, 2010)

(from the top)









Solder the collector of the transistor to the - main LED terminal.










Prepare the resistor terminal by bending it 90º and tinning with a bit of solder.










Finally, stick the end of the resistor in the clay and solder it to the + side of the main LEDs (180º from the driver LED makes a nice spot)










The remaining resistor leg is the + terminal for your $HIT and the transistor emitter is the - terminal. So nothing left to do but plug it in and test it all out:






Once you get 'the hang' of it, you can make several $HITs fairly quickly.


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## debbie5 (Mar 2, 2007)

Mmmmmm..LED's in a cookie! YUM!


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## SPOOKY J (Nov 20, 2009)

Very cool. Great idea with the clay.


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## corey872 (Jan 10, 2010)

One last tidbit - a sharp eye might notice the flicker LED I used is flat on top. I ground the top flat and polished it, so I could get a look at what is inside. Amazing to think some company is making these little circuits, assembling the LED's, putting those in a case with a switch and battery, packaging them, shipping half way around the world, Dollar Store gets a hold of them, sells them 2 for a dollar - and there is still profit in the whole deal!

I labeled a couple of highlights. Ball point pen is for scale.


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## GOT (Apr 17, 2007)

This is great, but I have never found a type 2 LED. Where can I get some?


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## corey872 (Jan 10, 2010)

I grabbed mine at the Dollar Store., two in a package for literally $1. Been so long, I forgot the brand name. Though most of the cheap ones seem to be LED only - which is actually easier for us! 

I picked up some Christmas tea lights on close out at target last year. They have a big 'ol circuit board which fills the diameter of the tea light.

The flicker LED's seem to be remarkably durable. I've hooked them up with reverse voltage, over voltage for just a second, etc - and they keep on going. I had some circuit boards a few years ago and one accidental contact with reverse voltage and the board was toast.


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## corey872 (Jan 10, 2010)

Just wanted to follow up on this. I have three batches of these: 6 in landscape lights, 4 in 'candles' for the front window and 4 in 'candles' for the mantle. They have been running almost continuously for the past 2-1/2 months...I'd estimate ~1500 hours or more. Just change the paper shade and they go from Halloween to Turkey Day/Fall to Christmas. So, as I mentioned above, the single resistor isn't the 'proper' way to do it, but doesn't seem to affect longevity in this case.


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## phillipjmerrill (Mar 19, 2009)

Do you have a preferred supplier for electronic components?


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## corey872 (Jan 10, 2010)

Oh, nothing specifically - usually where ever I can scrounge cheap components. In this case:

Tea Lights - Dollar Tree store
'Straw Hat' LED's - Ebay
2N2222 transistors - Ordered with another batch of stuff from Digikey.com, but might be cheaper with some other order if that is all you need.
Resistors - so old, I've forgot where they came from
5V SMPS power supplies - Ebay

You might be able to order everything under one shipping fee from digikey, mouser, newark, or possibly even some surplus places (allelectronics, meci, etc)


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