When building a home monitoring "nanny audio cam" system, the main component seems to be microphones/sound pickups.
The qualities that I think I need for such microphones for this system seem to be:
Sensitivity to somewhat loud human voice.
They should pick up human - including children - conversing in normal tones.
I do NOT need super-sensitivity to pick up whispers/quiet conversations (the main purpose of the system is dealing with some kinds of arguments/tantrums/altercations involving the children, meaning that anything less loud than a quiet conversation is irrelevant). Having said that, I don't need something special that will exclude quiet conversations either, just don't care about them.
Ability to pick up voice/noise in a fairly wide area - one per room.
Ideally, I'd like a single mike in a small bedroom or a large living room (25x30 ft?) each.
If that's impossible, a separate concern is interference between same-room pickups.
Very important. If there is shouting, I need to be able to tell what the shouting is about in detail, as if I was there, as opposed to merely the fact that voices are raised with unintelligible speech.
Look and feel.
I definitely do NOT need the microphones to be hidden. Looking nice/ergonomic is a slight plus but nowhere near a major factor.
Don't care about details, but ideally would be something that can be connected to a central recording hardware (PC-based). Does NOT have to be wireless, unless distances are somehow a concern for sound transmission quality over a given type of connector.
All things being equal, a pickup with IP connectivity (Ethernet port) would be the best, but NOT at the cost of more important features.
I'm unsure of what my options here are, but preferably below $100/piece and ideally below $50/piece. However, I'm more concerned with functionality than price, if these price points can never fulfill my needs.
So, my questions are:
What are the possible kinds of microphones that fulfill my needs that I should consider?
What technical specifications should I look for in such microphones?
What are the other factors I failed to consider in the list above given the stated purpose of the system (see background section below for details).
What are the extra features I should consider in the microphones for such a system?
Are my cost price points above even remotely reasonable for the features/factors I desire?
I'm looking into a project of building an audio home monitoring system. Most of existing security/monitoring systems I'm aware of seem to be video centered, and either lack audio, or have very poor audio quality.
The system would be for "nanny cam" type of situation monitoring - e.g. ensuring real-time or post-factum that no bad behavior occurs verbally in the house when other people with lower level of trust are there - e.g. nanny/babysitter and children.
The main purpose of the system is dealing with some kinds of arguments/tantrums/altercations involving the children, either for me to be able to call in real-time to intervene, or to investigate exactly what happened later.
I am planning to ask a series of questions related to building such a system, and on Meta it was indicated that such questions are on-topic