thetechnobear They way sensing with the Trill BAR and SQUARE sensors works is actually different to that approach. In this case, one axis is given by interpolated readings between adjacent sensors.

You can read a little bit more about this sensing technique here: https://www.nime.org/proceedings/2012/nime2012_195.pdf

However, we plan on having a tutorial for building different sensors using the Trill CRAFT and conductive material.

thetechnobear I guess then you become mostly limited by the data rate of I2C? (give i2c allows for 127 slaves)
(hmm, and I guess there might be a limited i2c address count on CRAFT)

In its current configuration, you can program up to 8 different addresses per sensor (on hardware, via some external pads) and each family of sensors (CRAFT, BAR & SQUARE) will have a different address range, meaning you will be able to use 8 of each on the same I2C bus.

        thetechnobear Bela could stock some things like copper tape, conductive material, conductive paint - that could be added onto the kickstarter order at the end. (or even just a 'starter kit')

        That's a great suggestion! Some of these materials would be a hassle to stock & ship for us (conductive paint, for example), but some others we may be able to provide with the kits.

        Stretch goal, maybe? 🙂

          adanlbenito

          ah, thanks for that paper ... all clear now...

          so each channel is capacitance on a gives surface, then you interpolate that to get position - neat.
          the X/Y is particularly a neat implementation, having the longer connected strips allows you to reduce the number sensors (over having a simple grid of sensors) - very cool.

          I guess, creating that grid by hand is pretty tricky, as you need to find a way to get a wire to each block to take back to the sensor.i could imagine some kind of (wood) back plane with holes (for wires)... but creating a good contact with the copper layer is tricky ... hmmm, have to think about that.

          yeah, I think copper tape is probably the thing id most like.... also the plastic template tool you show for cutting could be useful too.

          the thing Ive noticed with DIY, is whilst I can track down most of this stuff - you end up buying from multiple online suppliers, which not only takes quite a while to track down - but also means shipping starts to really add up. (as they all tend to have a minimum shipping or order size)

          also generally, I think backers really like 'complete' kits , a bit like lego or eurorack kits, where you order it, and you know you can just start assembling... then of course, with that experience, you can then start venturing off and modding/hacking 🙂

            How sensitive are the sensors?

            I'm just wondering if they could be used with pots/encoders to tell when someone is touching them?

            You can actually sense a tiny bit of capacitance through a small plastic knob, so in principle, assuming the pot's case is NOT grounded, then you could give this a try. I tested one just now, but it will probably depend heavily on the actual layout.

            Hi Guys,

            I got the email about the Hex and Ring.

            How many sensors are on the hex? Do you have some design docs?

              AndyCap The Trill Hex will behave in the same way the Square does and will use the same number of sensors (30 in total).

                So the hex just a different shaped Square?

                My maths isn't great but I could understand 19 sensors if the edges were not straight, or 19 full + 12 partial sensors if the edges were straight.

                I'm trying to work out how you could combine 8 of these to make an isomorphic controller?

                  AndyCap The Hex will use the same sensor tech as the Square, but most likely with a finer spacing of the pads. Like the Square it will have two sliders of 15 elements each, at 90 degree angles to one another (but truncated to the overall outline of a hexagon). Since we expect the Hex will be smaller overall than the Square, the resolution can be somewhat finer.

                  You could cut down a Square to get a Hex, but this variation is more convenient in that you get consistent, repeatable results (which not everyone will have the tools to do), and as above, slightly finer resolution.

                  When we say you can use 8 sensors at a time, this is the number of unique I2C addresses that are available on each type of sensor. There's no limitation on using more sensors, if either (a) you use multiple I2C busses, or (b) you put custom firmware on the device with a different range of I2C addresses. Ultimately the main limitations to how many devices you can put on a single bus are the rise time of the bus and its total bandwidth. I would expect 20-30 devices should run relatively comfortably provided they had unique addresses.

                    Hi @andrew

                    Thanks for the info, I'm still a little confused though!

                    The email mentions isomorphic controllers which I took to mean something like:

                    Is each trill hex multi touch so would contain multiple smaller hex keys as in the image?

                    Or is each trill Hex single touch like an individual hex key in the image?

                      with CRAFT, i assume it reports all 30 sensors data (continuously)

                      for SQUARE/BAR/HEX etc is this still the same... i.e. they report all 30 sensors data, and then the 'interpolation' to touch is done on Bela (or whatever) , or is this done on the hardware? if the later can you get it instead to report the underlying sensor data?

                      AndyCap i have one of those :-) and i added "aftertouch" to it (with an axoloti and some fsrs). and as you i was wondering what exactly they meant with that email...

                        AndyCap The Trill Hex will be a 2D slider -- within the hexagon you get two axes of sensing, plus contact area. If you wanted to divide that up in software into smaller virtual keys you could.

                        If all you want is a single number for activation within each hexagon, you could make an isomorphic controller with a lot more hex keys using the Trill Craft, with one pad per hexagon.

                        @thetechnobear The interpolation can be done on the Trill chip, or you can request the raw sensor data. The former saves time and bandwidth but the latter lets you implement your own tracking algorithms.

                            andrew @thetechnobear The interpolation can be done on the Trill chip, or you can request the raw sensor data. The former saves time and bandwidth but the latter lets you implement your own tracking algorithms.

                            perfect, thanks @andrew

                              22 days later

                              A question about these (apologies if this has already been answered somewhere) - is there some way to get them to work in PD? Would they need a special library of some sort?