As technology grows, so do Spy Cameras and in this day and age you can get some pretty high tech ones! There are cameras which can now text message you if you are out of your home and a burglar breaks in. These types of cameras have motion sensors in them and they pick up anything which moves within the line of the sensor. Obviously this type of camera is not suited to those who have a cat or dog which roam freely in the line of the camera, as they will set the alarm off all of the time.
Generally the Spy Cameras with motion sensors are the best ones to go with as they do provide better security. You can get ones which either set off a sound alarm when they detect movement, or you can get ones which set off flashing lights outside of the home for other people to see, or you can even get a combination of both. It all depends upon your security needs and what would make you feel safer. Obviously the more high tech ones will cost more money so that needs to be taken into consideration when you are on the lookout for one. Overall as technology grows, Spy Cameras will also develop and become more high tech.