Use a thermal imaging camera and software to detect when your hand is too close to a saw blade and shut down the saw. This could work for any dangerous tool or equipment. Setup would be simple: plug the equipment into a control box, mount the camera pointed at the blade area, then use the software program to mark an exclusion zone. When the camera and software detect the temperature of a hand in the Safety Zone it shuts off. While your hand is still a safe distance from the blade! The software could be as simple as looking for a minimum number of pixels that are in the temperature range of skin. Or complicated enough to recognize the shape of fingers or a hand.