I bought my own fire alarm (i am an enthusiast) on ebay. I went into my garage to record it. And it didn't work. I tinkered with it a little and got it to work. And this is what it sounds like. Feel free to use with no credit.
I opened the woodstove door while recording with a zoom h1 n. So the first thing you hear is the door opening, and then the latch falling down. The fire had just been lit. It is starting to ignite the douglas fir wood slowly but surely, and you can hear the kindling crackling.
Some generative campfire sfx made with sunvox. The crackling sounds were made by taking some highpassed white noise, ring modulating it with some more white noise, and then using a noise gate to usilate the loudest 'crackles'. The rumbling was created using lowpassed white noise. Everything was sent into a reverb and a stereo expander.