Or do they only enhance and amplify sound
If wired together you need to find the one that is telling the others he thinks there's a fire. Usually a slightly different color indicator. Next time they go off, LOOK at them closely. If all have green led execpt one has red, for example, disconnect that one from the system. Try that for a week or two. If that fixes it, try a new battery in the culprit unit, and if that doesn't work replace that unit altogether. Also check for excessive ion sources in the one room with the culprit (dust, cig smoke, kitchen?) Depending what renovation was done after the fire there could still be plenty of smoke ions floating around. If more than one unit is alarming that may be your problem. Try air purifier, cleaning carpets, sponge down walls, etc.
analog sensors take one form of energy and convert it to another, in this case, electrical energy. microphone: acoustic to electrical piezo: pressure to electrical thermistor and thermocouples: heat to electrical photo detector (many types) : light to electrical hall effect device (not a switch type; that's digital, ie. on or off) : magnetic to electric coil: moving magnetic field to electric Antenna and receiver front end: electromagnetic radiation to electrical. etc, etc, etc. And you can use IC's. There are a lot of analog IC's. So you may want to buid a device to see how temperature affects accoustic transmission, or how pressure affects the strength of a magnet, etc, etc,
That's the impression we get when reading about them. They are not necessarily all wild and crazy. But yeah, they can be pretty scary indeed! ^_^ They maybe tend to not incline toward critical self-examination as much as, say, the water signs. They don't dig too much inside themselves. They're pretty bold by nature. Initiators. Brave. That's what makes them interesting to me. I'm a Pisces. :-)
