Android/Windows: Home monitoring systems can be expensive if you have to buy all new hardware. Why bother, when your old phone has a perfectly good camera in it? Perch can use that camera, plus a lot more.
Perch allows you to set up an old phone or tablet as a camera to monitor sections of your home. You can get alerts sent to your current phone when there's motion in a specific space. If you have a home automation system, you can even use Perch to remotely turn on or off lights and control appliances.