There are plenty of decent security cameras around. If you already have a spare smartphone, there is no reason no to use it to keep an eye on your home. Alfred can help. You will need two Android devices to get started. Alfred not only lets you keep an eye on your place, it also offers motion detection. You can have multiple cameras and viewers. Since you are using two smartphones, two-way communication is possible. Alfred also lets take snapshots from your smartphone. Like what you see? You can find Alfred on Google Play.