Picture of Automatic reminder/warning using audio greeting card

My kids are always leaving the side garage door open when they take out trash or recyclables and I'm always yelling at them to close the door because It could be a way for some undesirable/varmint to get in and sometimes it gets really cold/hot/rainy and I have some tools and equipment that may be affected by it. I just want it kept closed okay?
 So last Mothers day we were in Hallmark and I got an idea to automatically remind someone to close the door using one of those audio greeting cards.You can use this on any door even a fridge to belittle you when your getting that midnight snack.You have to use the kind of card that you can record your own voice not the pre-recorded type.

Step 1: Parts/tools needed:

Picture of Parts/tools needed:

Record your own greeting card about $5.00-7.00
magnetic reed switch (shown) like the kind they use on burglar alarms (fry's or other electronics store about $3.50)
(optional) candy tin or small project box
some extra stranded wire 20-24 gauge or thereabouts
wire cutters
soldering gun/solder