eli5. How do table saws with an auto stop tell the difference between wood and a finger?

Question

eli5. How do table saws with an auto stop tell the difference between wood and a finger?

In: 6214

Answer 1

Here is a video with a woodbutcher explaining and demonstrating with a super slo mo camera…….. https://www.youtube.com/watch?v=SYLAi4jwXcs