What type of pressure or weight sensors are thin? (Arduino or R-Pi)
You could perhaps try using Graphene Putty.  There are directions for making your own here.

Maybe an array of wires with a blob at the intersection of each wire would produce a change in resistance related to walking on the grid.  The bare portions of the wire would have to be offset to avoid the possibility of shorting by pressing them through the putty.

If you constrained the putty within a thin ring between two conductive strips, you could probably avoid the possibility of shorting the conductive strips when the crosspoint is compressed, but still measure some change in resistance.

And even if it doesn't work, you still get to play with Silly Putty(R).




  Graphene Flagship researchers from Trinity College Dublin in collaboration with the National Graphene Institute (NGI) at The University of Manchester, have used graphene to make a polysilicone polymer, known commonly as the novelty children’s material Silly Putty®, conduct electricity. Using this conductive polymer they found that they were about to create sensitive electromechanical sensors. The team’s findings have been published in the journal Science*.