Read the statement by Michael Teeuw here.
Reflective Materials on Touch Screens
Re: touch screen not working through acrylic mirror I’d like to open this topic again. It seems any clear material I place over a touch screen senses touches yet if the clear or transparent material has refective tint It will not pick up touches. I assume this is because the sensor only refects itself but is this the case. Touches can be picked up through paper which should block out any touches from the sensor so what could really be happening. Would the refective material need to be conductive and only refective on one side or is it all in the material thickness or maybe it’s all about contact with the screen. Any one have some insight?
@aandrew7 capacitive touch (which is the most commonly used touch tech at the moment) is reading changes in the electromagnetic field of the touch matrix caused by say your finger.
This means that ANY material that is conductive will disable the touch functionality.
This is why capacitive touch works through glass, wood and paper etc
Most mirrors (regular and two-ways) rely on some sort of metal coating to get the reflection properties and this is what disable the capacitive touch.
For the diy home user the best way to get touch on a magicmirror is by using IR touch, or something like the airbar, but that has limited functionality at the moment.