In the past twenty years, devices such as nanny cameras have moved from the domain of the rich and famous and into the living rooms of ordinary, nine-to-five working folk. The same is true of formerly unaffordable technologies like door and window sensors and motion detector alarms.
Indeed, to say that window alarms now cost about as much as a few burgers from McDonalds is really no exaggeration. You can purchase contact pads, the simple magnetic components for door and window alarms, at large hardware and department stores, often at bargain-bin prices of under five dollars. These magnetic pads form a circuit which, when broken, signals the central alarm hub and gets that siren sounding. Even for someone with little experience in terms of working with hardware, taking on the task of installing contacts as part of their home security surveillance system will probably not pose much of a hurdle. You scarcely need more than the cabling, the contacts, some wood glue and a silicone gun. This is a service you can also have done for you by the majority of security companies, though you won't get their best prices unless you've signed up to use them to monitor your alarm system.
Installing contacts should be your first priority, as they constitute the first line of your home security surveillance system's defense against that hostile world trying to break into your home. The second line, should someone succeed in breaking in by smashing or cutting the glass of your windows, should be motion detector alarms. These are also fairly inexpensive. There are a few different types, which use different technological principles but wind up having pretty much the same effect. UWB (Ultra-Wideband) radar detectors are one. These emit sonar or radar signals, the same technology used to, you guessed it, detect enemy submarines in times of war. If the signal such a device emits gets bounced back sooner than expect, the device will register that something has moved across its detection field, and activate the alarm siren.
PIR motion detector alarms are the more common variety in modern home security surveillance systems. The acronym stands for 'passive infrared', as these devices passively sit and 'stare' over a fixed distance, registering the heat of the various objects in that area. If the temperature of that area changes in just one place (rather than ambiently), the motion detector will register that as motion. These are the kinds of devices you'll typically find over peoples' front doors or driveways, used to switch on a porch or outdoor light when they sense any disturbance.
Out of all home security surveillance system components, nanny cameras are probably the devices that have evolved the most. From the fuzzy, pixilated footage of yesteryear, these devices are now more sensitive than most human eyes and can be easily rigged to stream their footage to your very own secure website, allowing you to check on your baby even if you happen to be a continent away with nothing but a cellphone.
You can even have the data gathered by your home security surveillance system sent to a remote online storage cluster. Such clusters sell users whatever quantity of space they require at low rental rates. Assuming you're using a looped system of recording (which is really the wisest option, as multiple nanny cameras might record many terabytes worth of footage if left running for too long) you could purchase enough space to store days or weeks of footage for later perusal.
Still, this is only cost-effective up to a point. Luckily, there's a simple way to get around the need for making excessively large quantities of storage space one of the costs of your home security surveillance system. All that you need to do is have you motion detector alarms and door and Radar Detector Hub window alarms wired to your nanny cameras. If you set this system up in such a way that the various sensors or detectors set your home security surveillance system recording when there's movement in the house, you'll wind up eliminating the need for redundant recordings of empty rooms. You can also get cameras programmed with motion detection software to begin with - these will actuate this function without the need for any fancy fiddling on your part.