candle frequencies
Re: candle frequencies
That's the strangest question I've seen here 
Ok, I make a guess here: you want to drive a light (maybe a led), so that it imitates a candle. I have seen it on some restaurant' tables. If that's your intention, you can modulate the intensity by a sinewave whos frequency would vary randomly between, let's say, 0.5 Hz and 4 hz. Just a guess.
Marc
Ok, I make a guess here: you want to drive a light (maybe a led), so that it imitates a candle. I have seen it on some restaurant' tables. If that's your intention, you can modulate the intensity by a sinewave whos frequency would vary randomly between, let's say, 0.5 Hz and 4 hz. Just a guess.
Marc
Re: candle frequencies
i am making a flame sensor so want to filter all the other frequencies and only leave the candle flame frequency.thanx in advance
chal
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Sparky1039
- Posts: 1179
- Joined: 24 Nov 2005 20:07
- Location: Colorado, USA
Re: candle frequencies
There really isn't one. Candle flame (or any flame) is known as "black body radiation" and generates a "continuous emission" spectrum. This means the light energy emitted covers the entire visible and infrared bands. However, "continuous" means to the naked eye. In reality as the carbon molecules (candle soot) change quantum energy states it does indeed generate more discrete wavelengths of light (a whole bunch of them). But to resolve this requires the use of a mass spectrometer, a very complex precision instrument far outside the scope of a simple PIC project.can any1 tel me the actual frequencies produced by a burning candle
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Jack Flanders
- Posts: 337
- Joined: 17 Apr 2008 02:53
- Location: Fantasy Land
Re: candle frequencies
Flame sensors are actually quite easy and maybe a little surprising. At least, I was surprised!
I made one with a commercial sensor that works well. The thing to look for is short wave ultraviolet light. Flames produce short wave UV and it can be detected.
The detector is a two electrode bulb with some type of gas at a specific pressure. A "high voltage" supply bias (maybe 400Vdc) energizes the bulb. When short wave UV is present, the gas ionizes and current flows. The one I built can detect a butane cigarette lighter at >10 meters. No lenses required. It works outdoors in full sunlight also. The ozone layer filters out short wave UV.
You can get these here:
http://www.acroname.com/robotics/parts/R344-R9454.html
The price seems to have gone up since I bought one 5 years ago. I bought their signal conditioning board also.
They use them in robotic competitions where a robot must find a flame and squirt water on it to extinguish it.
I made one with a commercial sensor that works well. The thing to look for is short wave ultraviolet light. Flames produce short wave UV and it can be detected.
The detector is a two electrode bulb with some type of gas at a specific pressure. A "high voltage" supply bias (maybe 400Vdc) energizes the bulb. When short wave UV is present, the gas ionizes and current flows. The one I built can detect a butane cigarette lighter at >10 meters. No lenses required. It works outdoors in full sunlight also. The ozone layer filters out short wave UV.
You can get these here:
http://www.acroname.com/robotics/parts/R344-R9454.html
The price seems to have gone up since I bought one 5 years ago. I bought their signal conditioning board also.
They use them in robotic competitions where a robot must find a flame and squirt water on it to extinguish it.
