The invisible Play Pen
This invention is very similar to The Foul Ball Alert that I invented. They both use RFID technology to locate and identify things attached to a tiny transmitter/detector. It is the same technoloy that libraries use to protect their books from theives. You might have spotted the antenna tucked into the spine of your book.
The Invisible Play Pen uses this same idea to monitor children. The antenna above is placed on a child and the parameters on the receiver are set according to the area that you are monitoring. For example, the parent or guardian can set it to monitor a backyard or a playground sized area. An alarm is sounded on the reciever when the child wanders outside of the preset parameters. The distance that is protected can be a short as a few inches to as far as 300 feet.
There are many uses for this device and uses that aren't just limited to children either. This would be a good solution for caregivers of Alzheimer's patients, pet, and property owners.