SawStop: The World's Safest Table Saw

SawStop developed a table saw that stops and retracts the blade within 5 milliseconds upon contact with skin. The way it works is described on their website:

"The SawStop safety system includes an electronic detection system that detects when a person contacts the blade. The system induces an electrical signal onto the blade and then monitors that signal for changes. The human body has a relatively large inherent electrical capacitance and conductivity which cause the signal to drop when a person contacts the blade. Wood has a relatively small inherent capacitance and conductivity and does not cause the signal to drop."

The one minor drawback is that the system is single use only. Once the system is activated, you have to replace the braking system. This is because the brake is applied by burning through a wire that holds a spring that keeps the emergency brake away from the blades. This is a simple replacement and well worth it considering you just saved a finger!