The bad guys will always go for your safe to discover your secrets, so why not store them in plain sight with a hollowed out? Or, perhaps you need to hand off an item to one of your operatives -- use a hollow book as a dead drop, perhaps hidden amongst the stacks at a library or used book store...

This guide will show you how to build the classic secret hollow book safe. You'll also learn how to make a motion detection alarm using a Circuit Playground Express, and get a primer on the ultimate physical security app for Android -- Haven.

Materials & Tools

You'll need an old book that is no longer wanted. A great source for these can be a thrift shop or the used book store at your local library.

Hardcover books are nice to work with, but you can use a soft cover just as well. Be sure the book is thick enough to hold your items.

In hollow and seal the book, you'll need:

• Utility knife with fresh, sharp blade
• Straight edge
• Speed square
• Pencil
• Small paintbrush
• Mod Podge or white glue
• Sheet of Mylar or plastic cling wrap
• Small clamps (optional, you can stack heavy items instead)

Optional Android

If you want to try out the Haven app for capturing whomever is snooping in your book safe, you'll need an Android phone. It doesn't need to be a new phone, as Haven was written to run well on older devices.