Is it possible to use capacitive sensing to detect touch on or through a metallic overlay?
Answer
It is possible to detect a touch on a metal surface, but not through it. A metal overlay would be a single sensor and could not provide multiple touch inputs. To use an overlay as a capacitive sensing sensor, connect the overlay directly to the capsense pin.
Capacitive sensing on a metallic overlay
Chinese version
http://community.silabs.com/t5/Silicon-Labs%E4%B8%AD%E6%96%87%E6%8A%80%E6%9C%AF%E8%AE%BA%E5%9D%9B/%E5%85%B3%E4%BA%8E%E9%87%91%E5%B1%9E%E8%A6%86%E7%9B%96%E5%B1%82%E7%9A%84%E7%94%B5%E5%AE%B9%E5%BC%8F%E8%A7%A6%E6%8E%A7%E6%A3%80%E6%B5%8B/ta-p/157041