Trill & SuperCollider

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Trill & SuperCollider

Tapage

I've recently gotten my hands on the Trill-bar, Trill-square, Trill-craft, and a Bela mini. The plan is to use the sensors with the Bela running SuperCollider code. I found a great blog by Jonathan Reus in which he discusses his Banjo project that uses the Trill-craft in combination with a Bela running SuperCollider.

https://blog.bela.io/2020/06/05/hacking-the-banjo-jonathan-reus/

I've downloaded and installed the software from his Github but when I run some test code on the Bela it didn't seem to recognize the Trill-Bar.

I was wondering if the extension he uses might be optimized for the Trill-Craft only? Or am I missing something else?

giuliomoro

On this repo you'll find two ugens: TrillRaw and TrillCentroid. You'll need the former for Craft and the latter for all the others.

Tapage

The TrillCentriod does not recognize my Trillbar:

Unexpected or no response.
No valid device connected.
1
Unable to identify device
ERROR: Unable to initialize touch sensor

I am running this code:

s = Server.default;

s.options.numAnalogInChannels = 8;
s.options.numAnalogOutChannels = 8;
s.options.numDigitalChannels = 16;

s.options.blockSize = 16;
s.options.numInputBusChannels = 2;
s.options.numOutputBusChannels = 2;

s.options.postln;

s.waitForBoot({

	{
	
	Ndef(\trill, {
    var i2c_bus = 1;
    var i2c_address = 0x28;
    var thresh = 0.22;
    var prescaler = 1;
    var centroids;
    
    centroids = TrillCentroids.kr(i2c_bus, i2c_address, thresh, prescaler);
    
    SendReply.kr(Impulse.kr(8), "/trillcentroiddata", centroids);
}).play(group: s);
	}.fork;
});

The example (I think c++) patch does work and does recognize the Trillbar

giuliomoro

The default address of a Trill Bar is 0x20, not 0x28. Can you try changing that in your code?

PS: please enclose the code you paste between triple backticks ``` so that it gets properly formatted.

Tapage

Ok, the IC-address seemed incorrect
changed it to what I need
now it says:

Underrun detected: 186 blocks dropped
2 mode switches detected on the audio thread.

Still not seeing anything happen

Tapage

HA!

added this to the code:

OSCFunc({|...args| args.postln;}, "/trillcentroiddata");

And I do seem to get a stream of data...
Now to make sense of said data
(5 fingers on the Trillbar)

[ [ /trillcentroiddata, 1001, -1, 5.0, 0.041217673569918, 2411.0, 0.27505388855934, 3281.0, 0.43345904350281, 4034.0, 0.61961209774017, 3437.0, 0.8310883641243, 3024.0 ], 35.383546892, a NetAddr(127.0.0.1, 57110), 57120 ]
[ [ /trillcentroiddata, 1001, -1, 5.0, 0.042295258492231, 2433.0, 0.2753232717514, 3292.0, 0.43345904350281, 4053.0, 0.61988145112991, 3457.0, 0.8310883641243, 3024.0 ], 35.508610767, a NetAddr(127.0.0.1, 57110), 57120 ]
[ [ /trillcentroiddata, 1001, -1, 5.0, 0.042025860399008, 2405.0, 0.2753232717514, 3301.0, 0.43345904350281, 4064.0, 0.61961209774017, 3456.0, 0.8310883641243, 3024.0 ], 35.633519975, a NetAddr(127.0.0.1, 57110), 57120 ]
[ [ /trillcentroiddata, 1001, -1, 5.0, 0.044450432062149, 2431.0, 0.2753232717514, 3305.0, 0.43345904350281, 4088.0, 0.61988145112991, 3449.0, 0.8310883641243, 3024.0 ], 35.758649725, a NetAddr(127.0.0.1, 57110), 57120 ]
[ [ /trillcentroiddata, 1001, -1, 5.0, 0.044181033968925, 2420.0, 0.2753232717514, 3301.0, 0.43318966031075, 4081.0, 0.61934268474579, 3407.0, 0.8310883641243, 3024.0 ], 35.883456058, a NetAddr(127.0.0.1, 57110), 57120 ]

giuliomoro

See this example

// returns an array with format: [num_active_touches, t1_pos, t1_size, t2_pos, t2_size, t3_pos, t3_size, t4_pos, t4_size, t5_pos, t5_size]

So:

// touch1 is a percussive pluck
touchsigs[0] = Pluck.ar(WhiteNoise.ar, (centroids[2] > 0), 0.2, centroids[1].linexp(0.0, 1.0, 70, 300).reciprocal, 5, 0.9);
		
// touch2 is a bendy PM synth
touchsigs[1] = PMOsc.ar((centroids[3]+0.001) * 2500, 500, centroids[4].linexp(0.0, 2000, 0.1, 12.0), 0.1, mul: 0.5) 
			* EnvGen.ar(Env.perc, (centroids[4] > 0.0), timeScale: centroids[4].linexp(50, 500, 0.3, 5.0));

// touch3 another percussive plucky sound with pull-off behavior
touchsigs[2] = Resonz.ar(
	Pluck.ar(PinkNoise.ar, (centroids[6] < 0.05), 0.2, centroids[5].linexp(0.0, 1.0, 80, 1000).reciprocal, 3, 0.5, mul: 6.0),
	centroids[5].linexp(0.0, 1.0, 800, 2400), 0.1, 4.0).tanh;

Tapage

I think this is what's going on...

OSCFunc({|...args| 
//args.postln;
"_nr of fingers_ : ".post; 
args[0][3].postln;

" position 1 : ".post; 
args[0][4].post;
" size 1 : ".post;
args[0][5].postln;

" position 2 : ".post; 
args[0][6].post;
" size 2 : ".post;
args[0][7].postln;

" position 3 : ".post; 
args[0][8].post;
" size 3 : ".post;
args[0][9].postln;

" position 4 : ".post;
args[0][10].post;
" size 4 : ".post;
args[0][11].postln;

" position 5 : ".post;
args[0][12].post;
" size 5 : ".post;
args[0][13].postln;
}, "/trillcentroiddata");

For some reason, I never get '0' fingers, but things seem to be working otherwise

giuliomoro

Tapage For some reason, I never get '0' fingers, but things seem to be working otherwise

Ensure you are not touching the Trill when you start the program. The sensor is calibrated when the program starts, and if you have fingers on it, things may get weird. Also, ensure there is no moisture on it. If a bit of moisture is inevitable due to the environment you are in, then you can adjust the threshold on the device to ensure no false triggering occurs.

Tapage

By the way, thank you so much for helping out!

Tapage

I've tried changing the
var thresh = 0.22;
value in the code from low to high and made sure the sensor was dry and untouched but I still get weird readings.
Is changing the threshold 'on the device' something else than changing it in the code?

giuliomoro

Please try the following:
- open the Trill/bar-visual project and run it. Go to http://bela.local/gui to see the visualisation. Do you see one touch when nothing is touching the sensor? Post an image of that

If you find a spurious touch above, do this:
- open the general-settings project
- change the sensor type in the C++ source code by replacing Trill::CRAFT at line 155 with Trill::BAR
- run the project and go back to the GUI as above
- send a screenshot of the page for each of the three settings "baseline", "raw" and "diff"
- if you see any of the black bars displayed while in "diff" mode while you are not touching the sensor, then these should hopefully be very small, and tweaking the "threshold" parameter should get rid of those.

Tapage

alt text

This is what I see without touching the bar

Tapage

alt text

Tapage

This is when I increase the threshold

alt text

Tapage

I do still have the same problems again when I go back to the SuperCollider code...

Tapage

I've tried to set the same 'thresh' and 'prescaler' values as in the general settings patch the SuperCollider patch still sees way more 'fingers' even when I'm not touching the bar and if I touch it with one finger it occasionally jumps to 2 fingers... with more fingers everything seems stable

Tapage

While messing around with the 'thresh' value I did notice the following:

EXCEPTION: Noise threshold '2.03' out of bounds. Must be an integer from 0 to 1.

is it expecting an integer? or is that just a mistake in the error it posts?

giuliomoro

Tapage or is that just a mistake in the error it posts?

it's an error of the error.
A couple of lines above that error line in here it says:

 noiseThreshold    noise threshold, float: 0-0.0625, with 0.0625 being the highest noise thresh

Could you go back to the Trill/bar-visual example and add this line

	touchSensor.setNoiseThreshold(0.04);

before touchSensor.printDetails(); and then run and look at the GUI again? is the touch still there?

There is another parameter that could be useful "minimumTouchSize". Unfortunately this is not (yet) exposed by the Sc ugens, but it's mostly equivalent to filtering out on the Sc side all the touches that are very small (by applying a threshold to the touch size value).

Incidentally, the reason why I am referring you back to the C++ API for testing first is because that's the one we have tested, and so I wouldn't want that you'd be seeing errors in Sc that are due to the Sc interface. Let's get to the point where it works fine in C++ and then consider how to best have that done in Sc.

Tapage

I've added the

touchSensor.setNoiseThreshold(0.04);

line and everything seems to work perfectly in the C++ example

I'm wondering if the settings in the TrillCentroids UGen are actually updated?