LED candles provide a convenient source of ambient light, without the risk of burning your house down. On the other hand, there’s (for better or worse) no scent involved, flickering tends to be somewhat unrealistic, and it’s pretty easy to tell it’s not actually the real thing.
Keith, however, has been on an intermittent three-year journey to change that with a candle that flickers realistically, emits smoke and smells when — literally — blown out, and is “lit” by a match.” This, of course, took some unusual techniques, including coating a jar with wax as an enclosure that still looks like a candle.
Inside, an Arduino Pro Mini powers six programmable RGBW LEDs, which can each flicker away randomly, for a more realistic flame effect. When a candle is placed inside the glass, an infrared sensor picks up on this heat energy starting the candle’s simulated flame. When it’s time to turn things off, a microphone sensor within picks up on someone attempting to blow it out, and a pulse of power to restive wire wrapped around glycerine and smelling oil provides both smoke and smells.
More info on how the candle was made can be seen in the video below, while the full project write-up can found here. Whether you need a faux flame like this or not, there’s quite a few techniques here that could be useful in a variety of other builds.