This is pretty impressive: a table saw that can distinguish wood from fingers. The video demonstrates this with a saw cutting through a board, but stopping before it slices a hot dog resting on the board. “The SawStop system detects contact between the hot dog and the blade of the saw and stops the blade in approximately 5 milliseconds or less,” according to the site. They have slow-motion footage of the blade doing just that.
The technology is apparently adaptable to other power woodworking tools. I don’t know how much it adds to the cost of items, but the fact that it works at all is impressive to me. Seriously, how the hell do they do that?
Oh. According to their explanation, it detects the different electrical properties of wood and flesh. If a user’s finger touches the blade, his or her body’s capacitance alters the electrical signal induced in the blade. The system detects this and brakes the blade. Clever.