A doorbell with a camera offers you the possibility to see who's at the door without opening it. It differs per brand whether you can view the footage on your smartphone or a digital receiver. In many cases, doorbells with a camera also have a video function. You can easily take pictures of the person at the door. Choose a model with intercom function so you can talk to the person at the door. This way, you can easily let the delivery person know where he can leave the package when you're not at home.