At my current class in VR we are working on Google cardboards. But the image quality is really a problem with my small iphone6. I have a hardcase VR glasses that I got a much nicer view in -but the problem was they got no button. It was quite easy to make a magnet button (just put a magnet on the outside cover) but really as in REALLY difficult to get a touch button fixed. I could not find any foil that worked som I ended up tearing apart som other cardboard glasses I had in stock.
Here is an image of my hack. To get some space to the screen I drilled a hole in side of the plastick. Glued the conductive paper to a bended metal strip. No I will probably go buy some other glasses soon – but it works for now.