This is a quick way to prototype pressure sensor with velostat/ESD foil. You will need a piece of velostat/ ESD foil, Aluminum foil, a sheet of paper, stick glue and scissors. (the photo below does not include velostat!)

In this example, I am using 5cm x 5cm piece of velostat. The size and shape could change depending on your velostat sheet size.

Cut off the paper that is double the height of velostat piece so it can hold velostat when folded in half. The width of the paper should be few centimeter wider than velostat piece. Cut off a strip of aluminum foil. You can make the aluminum foil as wide as velostat. This will determine the sensing area. Make sure that the size does not exceed the velostat. place the aluminum foil piece inside the folded paper base. Cut out the top side of the paper fold so you can place the crocodile clip that should grab the bottom side of the aluminum foil. Place the velostat in between the paper and fold it. Place the crocodile clip on end of each pieces of the aluminum foil.

Voila! now you’ve made a pressure sensor. Here I connect my multimeter and you can see it is showing the resistance change when pressure (i.e. weight of a glass) changes. The range depends on the type of velostat you have, size of electrodes’ (aluminum foil) surface area, how conductive your electrodes are… The one I made range from 12k ohm (when slightly touched) to 400ohm (when pressed really hard)

You can modify paper contact switch as pressure sensor by inserting a sheet of velostat between the contacts.