Four separate pressure sensors not only give feedback about where I’m pressing, but also how hard.
>> Pressure Sensor Matrix Instructable
The sensitivity is ideal for finger pressure. Though it is not linear, it is stable. Very sensitive to light touch and then it takes a lot of pressure to reach the minimum resistance. The inside looks just like the fabric pressure sensors, except each stitch is connected to a separate conductive fabric tab. The downside is that separate tabs and connections to these tabs take up a lot of space, especially if you want to achieve a tight matrix of sensors. A grid of lines and columns and some code to analyze these (separately power and measure) would allow for much tighter spacing. This version is nice because it is so simple.
The Instructable covers two slightly different versions of the pressure sensor matrix. The only difference being the spacing of the individual pressure sensors in the matrix. In one of them they are placed practically next to each other (white) and in the other there is a 1cm space in between each sensor (purple), but because of the thickness of the neoprene it is not possible to press in between the sensors without pressuring a sensor.
how bad is the crosstalk between sensors?
Reply: Maybe you can kind of see from the videos (I’ve added the playlist to this post). I find differentiation between inputs to be quite clear, it depends a lot on how precise you are with your stitches. The videos show a range of different techniques, but the neoprene version with conductive thread stitches and Velostat (or now Eeonyx) in between definitely have the nicest range and separation between sensors.