Some thoughts, consideration, and use case from personal experience in no specific order of relevance or importance. In special circumstances having the ability to listen with pin point accuracy on a target area that is extremely far has value to some.
Think border security, think defined choke point, think equipment monitoring, think high ambient noise. Having a very focused long range microphone can provide that aspect. These come in standard discreet element configuration and more expensive laser, RF etc.
Ultra Sonic: There are situations where it’s not about listening as is being able to alert, narrow, filter, direct a PTZ camera. In this case ultra sonic proximity sensors are ideal to detect and move a PTZ camera to a target area.
The same ultra sonic sensors also come in ranging types. Which offers incredible insight as to the distance & speed of an object. Again if connected to a security system it can help the network and user to focus its resources to the pending threat.
It goes without saying these types of sensors are prone to false alerts. As such when they are in use and deployed these sensors are NOT the $0.99 variety!
Radar: Only in the last ten years has radar technology come down to somewhat reasonable levels where a consumer could purchase that wasn’t military restricted technology. The obvious benefits of current generation of radar is the ability to operate in very extreme temperatures and weather conditions.
Think fog, pitch dark, high winds, extreme brightness.
Unlike any microphone and ultra sonic the latest generation of radar can track multiple targets and provide distance, speed, height etc.
There are countless other types of sensors that offer benefits in specific environments think microwave. Ultimately these different types of sensors help expand the range, reduce false incidence, target / narrow location, to increasing reliability.
As it pertains to the topic at hand there’s value in having discreet microphones that can focus on a target area. As others noted if the same needs to be recorded with video get ready to invest lots of time and resources to make it work!
When the same is only used in a live use scenario that doesn’t need video synching. The use of this technology has lots of value to those interested in CCTV security, nature, and environmental.
As it pertains to security cameras it makes little sense not to use, deploy the same.
Even the cheapest current generation of Dahua / Hikvision hardware offers twice the performance when compared to ten years ago. Some models easily capture crystals clear audio exceeding 100 feet in no wind conditions.
The same at 0-25 feet is truly incredible at times to hear and listen to!
