Someone over at xda found some a list of debug tools.
http://forum.xda-developers.com/show...53#post2509753
With test HTCSensorDemoAP.exe
you can view position of the diamond, ambient value , brightness level.
With NavDbgTool.exe you can actually test out the capacitive function of your phone. It also supports 2 fingers at once.
here is a screen shot. That the "S" letters were drawn at the same time with my fingers.