> Are there any lower voltage sound detectors out there?
None that I know of. There are some lower voltage, lower power op-amps out there, but I don't know of any sound detectors that use them.
You'll have to do some experiments with the sound detector to see what kind of battery life you can get from it. The data sheet I looked at says that the LM324 op amp it uses typically draws about 1.5 mA of current. Normal alkaline AA batteries have an energy capacity of around 1700 mAh, so that suggests that the batteries would last about 47 days if they were used for nothing but the sound detector itself. But it's hard to say whether this application is "typical" or not.
There are also higher capacity Lithium AA batteries that could could extend the life a bit more. I think the highest capacity these days is around 3400 mAh, which might get you up in the 90 day neighborhood.
I don't know how often you expect to change the batteries in the Monnit, even if it sends you a notification. Every 47 days or so seems like it would get to be a headache.
Overall, I think you'd be better off if you could power the sound detector from a small wall-wart power supply, even if it means you can't put the sound detector right next to the fire alarm horn. Since the horns are so loud, I think you may be able to place the sound detector a moderate distance away, where an AC outlet is available, and still reliably detect when it is going off.
None that I know of. There are some lower voltage, lower power op-amps out there, but I don't know of any sound detectors that use them.
You'll have to do some experiments with the sound detector to see what kind of battery life you can get from it. The data sheet I looked at says that the LM324 op amp it uses typically draws about 1.5 mA of current. Normal alkaline AA batteries have an energy capacity of around 1700 mAh, so that suggests that the batteries would last about 47 days if they were used for nothing but the sound detector itself. But it's hard to say whether this application is "typical" or not.
There are also higher capacity Lithium AA batteries that could could extend the life a bit more. I think the highest capacity these days is around 3400 mAh, which might get you up in the 90 day neighborhood.
I don't know how often you expect to change the batteries in the Monnit, even if it sends you a notification. Every 47 days or so seems like it would get to be a headache.
Overall, I think you'd be better off if you could power the sound detector from a small wall-wart power supply, even if it means you can't put the sound detector right next to the fire alarm horn. Since the horns are so loud, I think you may be able to place the sound detector a moderate distance away, where an AC outlet is available, and still reliably detect when it is going off.
