Although its still warm and nice outside (at least here in Sweden), winter is coming.
Whats the best approach to keep an eye on the fireplace?
I work from home, upstairs, and the fireplace is downstairs. Now and then I need to put in another log to keep the fire burning, but often I forget and have to start over. The notice of “need logs” needs to be automated.
I have thought of using camera to keep an eye on the fire, but I will probably forget that to.
I’ve also thought of using av lux sensor, but im not sure how reliable the information is, ie: low light could mean that the fire is coming to and end, but high light might mean that the sun is shining in from the windows on a sunny day.
How would you do it? Is image recognization an option?? Heat sensor (would trigger false alarms until the desired temperature is met although there is a fire)
I’ve got a slow combustion heater and pointed a MLX90614 sensor at it. It measures the temperature of the heater’s surface as well as the ambient temperature. I then calculate the difference - if the surface temperature is higher than the ambient temperature then I know the fire is still very well burning. Still experimenting with this setup, but appears to work reasonably well.
Why and how this device is marketed as a ‘flame sensor’ is beyond me. The used sensor, the YG1006, is a totally standard NPN IR phototransistor peaking at 940nm. That is in near infrared and is a standard wavelength used by things like IR remote controls, nightvision security cameras and is, well, emitted by the sun… Of course it will be unreliable, 940nm is literally everywhere. Even your clothing can reflect this wavelength when under incandescent lighting ! This thing being a ‘flame detector’ is entirely marketing blurb. Not even the manufacturer datasheet of the YG1006 mentions anything about flame detection. It’s just a totally boring and standard (and super cheap with bad specs) phototransistor to be used in your TV for receiving the remote signal. Don’t use this thing to detect fire. The consequences for it failing are far too dangerous.
To truely detect fire (and only fire !) you need a microbolometer operating in the longwave IR (LWIR) range from 8µm to 15µm. In other words, thermal imaging. The sensor from Melexis mentioned above does this. On the higher end of the scale, FLIR has some (pretty expensive) options too.
Yeah. The photodiode it uses is designed for IR remote controls and similar. Using it for fire detection is completely off-spec and doesn’t make the slightest sense. The diode peaks at 940nm, which is just barely outside the visible light spectrum. Fire does not have a peak in that range anymore than it has on visible light. That thing will be as ‘reliable’ as trying to detect fire using a visible light phototransistor, with all the false negatives and positives that would come with it. It will absolutely not detect radiant heat from a flame.
I read it similarly - you have a link to a good recomended one?
Use case: Going to mount it near the opening of the fireplace to detect when the fireplace is ON - I don’t want to automate the fireplace, I think you know how I feel about that, I want to do cool stuff to the HVCAC when there’s a fire.
Something like the Melexis sensor someone mentioned above (the MLX90614 or others, there are multiple derivative afair) should work reasonably well, as it measures radiant heat in the LWIR spectrum. It’s used in devices like contactless thermometers etc. Keep in mind that LWIR is blocked by most types of glass, so this may be a challenge. It’s still a little hacky though, but may be acceptable if this is only for some fun automations around the flame status (and not about automating the fireplace itself, as you said).
The most reliable setup for doing this is a thermocouple.
I just have a zwave temperature sensor about 6’ away from my wood stove. Once the stove starts radiating this sensor detects the heat up and then the hvac circulation fan turns on.
Mines a builtin fireplace gas unit, but there’s an access port on the left side with access to the back of the fire box where a heat sensor should work. Even with the brick insulation, I think the fire box is still hot back there (like 200 degrees) so pointing the MLX sensor at it SHOULD pick it up. Trying to figure out how to get power back there now…
All you people… I hate and love you all at the same time because while I have no practical need for this, I’m now ordering the sensor not because I need to but because I want to build this device . My wife’s going to love this one! “Honey, why is there a device by the fireplace?”, “Don’t worry about it hun, its just something else we don’t need that lets me geek out our home automation for no particular reason again”.
. My wife’s going to love this one! “Honey, why is there a device by the fireplace?”, “Don’t worry about it hun, its just something else we don’t need that lets me geek out our home automation for no particular reason again”.