I have just hired a nanny for my child. I want to buy a device that is easily concealed so I can hear and watch the nanny with my child. It may sound a little crazy but this will be the first person to watch my child besides my family and I'm a little nervous (I've seen way too many crime shows :) ). I just want to make sure she treats my child well. Also it has to be a device that will stay powered for a few weeks to a month on it's own and has good picture and sound. Thanks!