The piezo buttons worked perfectly for 4 years at ScottTv, but I think, I will try capacitive touch sensor buttons. Unlike the piezo buttons, they will not react if Scott is beating on the TV, but they will just work on the touch. Now I have to check if they are not too sensitive.
I use the same sewer cover as for the piezo buttons and the touch sensors breakout boards with the tpp223 chip.
To make the touch space bigger, I cut a piece of metal out of an soda can. I clued a wire on the metal part and solderd it to the PCB.
It is realy sensitive now and I think, that I need to add some kind of shielding around the backpart of the sewer cover.
Still a little Trial and Error to do.
They work also with 3.3V, so I could leave the adapter PCB away.