Anyone have plans or a site to build a LED Tea Light Candle that will flicker.
I thought there was a plan in Nuts and Volts years ago that used a yellow and blinking red LED but can't find it.
Thanks
Moe
LED Tea Light Candle
as I recall it was a basic stamp project using an external driver board. vast overkill. Probably about 1 year ago (sept issue, I think).
I made one based on a PIC12F629. Total parts cost was a couple of bucks. Schematic image: http://www.geocities.com/pcbs4less/candle/candlev12.gif
Source code: http://www.geocities.com/pcbs4less/cand ... -v1asm.txt
There were a number of things I didn't like about the N&V version, foremost was the way it flickered. I recorded the actual light from a candle as it flickered and then embedded it in my program via PWM.
The other thing I didn't like was the multiple color LEDs, I tried that out and couldn't get it to look very realistic.
The led I used was an ultra bright 20mA device. I tried a bunch of them and selected a Lumex ssl-lx5093SYC due to its color and output. I think adding a second similar LED would be good and have it slightly out of phase with first.
Placed in a paper bag or a thin walled PVC pipe, this looks pretty realistic. I beta tested the flicker on a number of friends and they all thought it was very realistic.
I made one based on a PIC12F629. Total parts cost was a couple of bucks. Schematic image: http://www.geocities.com/pcbs4less/candle/candlev12.gif
Source code: http://www.geocities.com/pcbs4less/cand ... -v1asm.txt
There were a number of things I didn't like about the N&V version, foremost was the way it flickered. I recorded the actual light from a candle as it flickered and then embedded it in my program via PWM.
The other thing I didn't like was the multiple color LEDs, I tried that out and couldn't get it to look very realistic.
The led I used was an ultra bright 20mA device. I tried a bunch of them and selected a Lumex ssl-lx5093SYC due to its color and output. I think adding a second similar LED would be good and have it slightly out of phase with first.
Placed in a paper bag or a thin walled PVC pipe, this looks pretty realistic. I beta tested the flicker on a number of friends and they all thought it was very realistic.
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Won't you have to run it from a pretty good source of power to actually substitute for a tea light in a food warming application?
Dean
Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).
R.I.P.
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).
R.I.P.
Thanks For The Reminder
I saw flickering LED devices at the dollar store (one up, non chain store). They had flickering LED candles two for $1 based on an LED. Looked real nice and was about the size of a Tea Candle. Ran on watch batteries I believe.
No trees were harmed in the creation of this message. But billions of electrons, photons, and electromagnetic waves were terribly inconvenienced!
Nice little circuit Philba Howlong do your tealights last?
All the ones that I have tried seem to only last a hour or 2 at the most. Is there any way to increase the life of the batteries, or use a supercap Unfortunatly, I realise that to keep the design down to "tealight " size...the size, and therefore the life of the batteries has to be kept tol a minimum.
All the ones that I have tried seem to only last a hour or 2 at the most. Is there any way to increase the life of the batteries, or use a supercap Unfortunatly, I realise that to keep the design down to "tealight " size...the size, and therefore the life of the batteries has to be kept tol a minimum.
Kim..The man with the cute little girls name...and Frankensteins face and body.
Get two flashing LED's of the same color. Connect them in parallel, wire them in series with a orange LED and a 9V battery. It will last for days.
When the power is first turned on the orange LED flashes normally, but in a short time the two flashing LED's get out of sync with each other and the
orange LED flickers like a flame.
When the power is first turned on the orange LED flashes normally, but in a short time the two flashing LED's get out of sync with each other and the
orange LED flickers like a flame.
uh, I'm sorry but not even close. put that in a paper bag (white or brown) and ask 10 people if it looks like a candle is in the bag - you will get 10 NOs. I spent a lot of time looking into flickering. it is not flashing - the brightness varies in a predictable fashion though there is a fair amount of randomness. Some people have used "strange attractors" http://en.wikipedia.org/wiki/Strange_attractor but recording the flame intensity worked better for me.k7elp60 wrote:Get two flashing LED's of the same color. Connect them in parallel, wire them in series with a orange LED and a 9V battery. It will last for days.
When the power is first turned on the orange LED flashes normally, but in a short time the two flashing LED's get out of sync with each other and the
orange LED flickers like a flame.
No Dean, they are not used for warming food. Just a warm glow.
Restaurant supply stores sell electric ones to replace the little votive candles. Some of the votive candles last 24 hours, and are about 2 inches high. The battery powered versions probably last for many days. They are popular in some restaurants now.
I'd suggest getting one from a restaurant supply store and hacking it.
Restaurant supply stores sell electric ones to replace the little votive candles. Some of the votive candles last 24 hours, and are about 2 inches high. The battery powered versions probably last for many days. They are popular in some restaurants now.
I'd suggest getting one from a restaurant supply store and hacking it.
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tea candle
Hi I do remember the issue was a October issue maybe 2000 or after. I will look for it when I have time. It used flashing Leds: red,2 yellow like you said built in a candle . I built it with just the bare flashing leds and was not too impressed. Tim Rasch [email protected]
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tea candle
Hi Again, I found the article in Nuts/Volts October 2000 on page 92.You were right one yellow [non flashing] in series with two flashing red leds in parrelel connected to +6v. The other circuit had two flashing red leds from +6v[ in parrelel] to ground through 100 ohm 1/4w ,a 10 ohm 1/4w at the high side of the 100 ohm going to base of a 2n2222,emitter to ground ,a 6v colored lamp from the collector to +6v. They suggest to try a 12v colored lamp to produce a nice candle effect. The lamps can have a current rating up to 200 ma. I didn't try the later circuit . I think it will work better. BTW the article is called: FLAME FLICKER SIMULATOR.It's designed to be put in a jack-o-lantern ,etc. Thanks for bringing up the subject!!!!!
Tim Rasch [email protected]
Tim Rasch [email protected]
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Candle simulation with LEDs
You all might look at Circuit Cellar #147 (Oct. 2002). Ching and Land made an effective candle simulation for theater productions using a yellow LED driven by PWM. The candle flicker was modeled using a random number generator and low pass filter to simulate actual, measured flame dynamics (1/f noise), previously published in a Japanese engineering journal. C code for the Atmel AT90 may be downloaded from the Circuit Cellar web site. I've used their model and it works very well.
Cheers, Jim
Cheers, Jim
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Candle simulation with LEDs - addendum
It seems that Philip Ching did the candle simulation as a student project, and the whole thing is also published on the web at Cornell. See
http://instruct1.cit.cornell.edu/course ... /index.htm
http://instruct1.cit.cornell.edu/course ... /index.htm
In an Nuts & Volts issue (December, 2002, #12), there was a really good flickering flame circuit in the Electronics Q & A on page 26. It used a combination a 555 timer "to produce the most realistic effect." If you want moe, I guess I can scan the page and send it to you if you don't have the issue.
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