• Trill

  • trill craft hexagonal "keyboard"

hi there,

i bought a trill craft (among other trills) during the kickstarter campaign.
i have a couple of questions, since i never worked with the sensors until now...

i would like to create a 30 (or maybe 60 with two crafts) arrangement of hexagonal touch sensors, much like this setup: https://www.c-thru-music.com/cgi/?page=prod_axis-49

my questions are:

-what is the minimum latency from touching a sensor to an output to a teensy via i2c? is it still 5ms, or less?
-will i be able to get some additional parameters additionally to the touched sensor? like, how hard it is pressed, or which direction my finger moves on the sensor (maybe by reading the nearby sensors as well) in order to get for example vibrato or aftertouch data...

sorry if these things are obvious but i have not dived into the capacitive touch world until now.

thanks

    lokki -what is the minimum latency from touching a sensor to an output to a teensy via i2c? is it still 5ms, or less?

    still dependent on bit resolution, see here https://learn.bela.io/products/trill/integrating-trill-into-your-projects/#scan-settings

    lokki -will i be able to get some additional parameters additionally to the touched sensor? like, how hard it is pressed, or which direction my finger moves on the sensor (maybe by reading the nearby sensors as well) in order to get for example vibrato or aftertouch data...

    You get an "amount of activation" which would roughly correspond to how much of the surface you are touching. As to get vibrato functionalities, you'd need to touch at least two pads at once. Typically, to make an "expressive" button you'd have two triangular pads like this (reaching the limits of ASCII art here):

    |-----|
|\    |
| \   |
|  \  |
|   \ |
|-----|

    this way, oscillating vertically will cause a change in the reading between the two pads which can be sensed.

        Hi Lokki,

        Great that you are getting around to experimenting with the Trill sensors. Using two Trill crafts to make a complex interface with 60 channels will work a treat. Here's a photo of an instrument I built using two Trill Crafts and pieces of brass. Each brass piece acts as a capacitive sensor with a variable reading.

        alt text

        You get a variable reading for each sensor channel so yes you can read something which is approximately equatable to pressure although as Giulio mentioned it is more a reading of how much contact is made with the capacitive surface rather a reading of the pressure applied.

        In terms of sensing the direction of finger movement you will need to think about the best layout for this and interpolate between multiple channels. If you have a look at the other Trill touch sensors you will see the kind of layouts we have used to make sure that a fingertip is always touching more than one capacitive pads at once (the zigzag shapes on the sensor surface). This allows us to calculate the position of the fingertip. You can definitely achieve similar effects with two or more pads close to each other or interlocked together. It's a lot of fun to experiment with as geometry plays a huge role in deciding the effectiveness of the sensing.

        Similar topics are touched upon in this tutorial, particularly the section about design your own slider with Trill Craft: https://learn.bela.io/tutorials/trill-sensors/working-with-trill-craft/

          3 years later

          bela_robert
          Hello, you wrote:
          Using two Trill crafts to make a complex interface with 60 channels will work a treat

          How is it possible to use two Trill Crafts ?
          How to change i2c addres of one of them?
          I cannot find any reference about this change.
          Thanks

            bela_robert
            Thank you!
            480 …. Incredibile !!!
            Your project is fine!
            Is there a video making sounds to see how to use it?