lokki can I expect to get a proximity reading from a sheet of fabric around 20cmx100cm? or would it have to be larger for that?
The larger the sensing surface (and in general the higher the capacitance of the conductor connected to the capacitive channel on Trill Craft), the larger the baseline reading will be. For large baseline values, the capacitive reading may saturate before you even get close to - let alone touch - the sensing surface. At that point you would have to reduce the prescaler (think analog gain) setting in order to get enough dynamic range. However, with a reduced prescaler (again, think analog gain), you'll get smaller effect from proximity. You should therefore try to minimise the baseline capacitance of the sensing conductor. I think using shielding for long wires and small (and/or hatched) pads helps achieve that. You can try things out on a Craft, use the general-settings example, set it to RAW mode and observe the readings when nothing is connected, then connect a long unshielded wire to one channel, then connect a long shielded wire to another one and see how they compare and also how it changes when you add a larger sensing surface. Increase the prescaler every time the pad saturates with nothing touching it or in its proximity and see if you can get to a working state.
lokki -if I connect one piece of fabric to a trill craft and it works as expected, should the rest of the sensors behave similar? or will the whole system be dependant on how many sensors are connected and how close they are to each other?
I have only seen crosstalk when I had shorted one of the sensing pads to ground, then all the other pins would read saturated. I don't remember seeing interaction between pads otherwise, but it may also be that I have not been looking with enough attention. With the test above you can see whether adding large capacitances to one channel affect the neighbouring one. BTW, if needed you could in principle use a different prescaler setting for each sensing channel, although that would probably slow down the sampling rate and is easier and faster to do with the upcoming rev3 firmware (which can be retro-flashed on existing devices). Let me know if you want early access to try it out.
lokki how would long wire "sculptures" behave
I don't know the details, but this worked with Craft, so there's hope!
