The price range for spy equipment is quite large. You can purchase high priced nanny cameras or you can purchase cheap spy equipment. Some of the lower priced items can provide you with the answers you need. If you have an intruder problem, I have the answer for you. Many spy equipment retailers offer a telephone that detects movement. Place the phone facing the door. When the door opens you will receive a phone call directly to your cell phone. You will then be able to hear what is taking place in your home. If no one should be there you can be pretty sure that the person in your home is not welcome. This device and many others can be found on eyespysupply.com.