There are 4 distinct different kinds of hidden cameras. Each has their own pros and cons. The different types of hidden cameras are different than the objects they can be built into. For example, a wall clock can be made into any of the different types of hidden cameras.
These cameras have a built-in memory card and record to themselves. There is no external DVR or recorder needed – each one is a complete hidden camera solution with nothing else to buy. Video is stored on an SD memory card and played back using a computer or TV.
Pros: One piece solution with nothing else to buy.
Cons: Live viewing isn’t available. Only record and then playback later.
These hidden cameras interface with the wireless network in your home or office. Viewing is done using your computer, tablet, or smartphone. Recording be accomplished by using a computer on the same network with the recording software. Playback is also done using that same computer. The computer is only needed if you wish to record.
Pros: Easy viewing on smartphone
Cons: Recording requires use of computer
These hidden cameras have a mini wireless transmitter hidden inside of the object. They transmit the video to the included receiver. The receiver then connects to your TV or DVR for viewing and recording.
Pros: Good solution for live viewing and recording when used with DVR
Cons: External DVR is required and that is an added expense.
These hidden cameras have a video cable coming out of the object. This cable then connects to your TV or DVR for viewing and recording.
Pros: The least expensive solution for a hidden camera
Cons: Cable between camera and TV or DVR is often difficult to hide.
The video below also helps explain the different types of hidden cameras.