A Trip Wire
It’s just enough to buy you a few precious seconds to get to a safe room, or give you the upper hand in a struggle for your home.
Connecting this wire to an alarm system will add more protection. Yes you could connect this trip wire to more lethal things, but for the sake of others involved in your life, don’t do it!

Thumb Tacks and Razor Blades
You can dismantle a door handle, make cuts in the handle and place the razor blades in the cuts to make it less noticeable. When someone is chasing you, it’s not like they’re going to be familiar enough with your house to notice that there’s something off about this handle.

Tasers & Door Handles
This one can be a bit dangerous, so only set this up if you have a way to break the circuit (by flipping a switch or something on the other side). This involves running a wire from an electrical source, either a taser or a small battery, to the door handle. There are ways to mount these wires into the door frame and set it to a wall mounted switch. That way all you have to do is shut the door behind you, flip the switch and there you go!

For booby trapping your home, keep in mind that it's often not just you in the house. Your little ones may not appreciate you putting razor blades on the door handles, and neither will child protective services.

Plus, if you have booby traps and for some reason get investigated by the police, you've pretty much guaranteed yourself some jail for attempting to harm an officer of the law. Fair warning.

That said, the best idea on here is the taser to the door knob. What makes it great is if you have a tripwire alarm on the property that alerts you, all you have to do is flip a switch to electrify the door knob to at least give yourself that little bit of extra safety while you call 911 or decide between the revolver or the shotgun.