Stitching conductive thread into neoprene to create a pressure sensitive pad. This sensor is very similar to the Fabric or vis-versa. And also close to the Fabric Pressure Sensor, but the difference is that the conductive surface is minimized by stitching only a few stitches on either side with conductive thread. This creates a good fingertip pressure range.
The resistance range of these pressure sensors depends a lot on the initial pressure. Ideally you have above 2M ohm resistance between both contacts when the sensor is lying flat. But this can vary, depending on how the sensor is sewn and how big the overlap of the adjacent conductive surfaces are. This is why i choose to sew the contacts as diagonal stitches of conductive thread – to minimize the overlap of conductive surface. But only the slightest touch of the finger will generally bring the resistance down to a few Kilo ohm and, when fully pressured, it goes down to about 200 ohm. The sensor still detects a difference, right down to about as hard as you can press with your fingers. The range is non-linear and gets smaller as the resistance decreases.
Materials: Neoprene, conductive thread, stretch
Tools: Sewing needle, fabric scissors, iron