Trill scan settings in Pd

Sharptone

Hi, I would like to play with the speed and bit depth values in Pd for my trill craft sensor.

This is my current Pd trill setup:
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, updateBaseline mycraft_48]

From the Bela Knowledge Base I found this piece of code probably in C++ :
touchSensor.setScanSettings(0, 16); // 0 = ultra fast speed, 16 = 16 bit resolution

How could I incorporate this to my current Pd trill setup?

giuliomoro

I just pushed an update to the dev branch that should allow you to do that, including an updated example.
[scanSettings mycraft_45 0 16( should do it.

Make sure you update your code to the dev branch as explained here.

Sharptone

Ok, I tried :
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, scanSettings mycraft_48 0 16, updateBaseline mycraft_48]

It seems to create an updateBaseline error as follow:

MIDI verbose: 0
bela_trillCreated: mycraft_48 Craft 48 Diff
1 mode switch detected on the audio thread.
int Trill::updateBaseline(): failed to read ack for command 6
bela_trillCreated: mycraft_49 Craft 49 Diff
The following MIDI devices are enabled:
Num Name In Out Pd channels
[ 0] hw:0,0,0 x x (1-16)
bela_trillCreated: mybar_32 Bar 32 Centroid
3 mode switches detected on the audio thread.
root@bela ~/Bela#

Sharptone

Ok, I put the scanSettings in the last position like in the example and it now seems to work.

[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, updateBaseline mycraft_48, scanSettings mycraft_48 0 16]

I wil play with it now, thanks!!

giuliomoro

Hmm I think that you need to updateBaseline after setting the scansettingd or the differential readings will be off.

Sharptone

At first like the above I tried:
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, scanSettings mycraft_48 0 16, updateBaseline mycraft_48]

and got this error:
int Trill::updateBaseline(): failed to read ack for command 6

Then I tried:
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, updateBaseline mycraft_48, scanSettings mycraft_48 0 16]

and the error disappeared.

giuliomoro

Yeah I get that, but it won't give you usable differential data I think. Do it in the order I recommend but send the updateBaseline after a 100 ms delay, see if that gets rid of the error. In general, keep in mind that the scan rate will be much slower at 16 bit. According to the table here, it will take 2.8 ms * 30 = 84 ms to scan the thirty channels, so your scan interval should be reduced accordingly.

Sharptone

Ok, I tried:
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, scanSettings mycraft_48 2 14]
│
[delay 100]
│
[updateBaseline mycraft_48]

results:
bela_trillCreated: mycraft_48 Craft 48 Diff
error: delay: no method for 'mode'
error: delay: no method for 'prescaler'
error: delay: no method for 'threshold'
error: delay: no method for 'scanSettings'
bela_trillCreated: mycraft_49 Craft 49 Diff
bela_trillCreated: mybar_32 Bar 32 Centroid

Note, I also tried other scanSettings values of 2 12, 0 9 and 4 9 without the delay and with updateBaseline as the last argument and got no errors:
[mode mycraft_48 Diff, prescaler mycraft_48 5, threshold mycraft_48 0.05, scanSettings mycraft_48 2 12, updateBaseline mycraft_48]

Other scanSettings combinations don't work. There are too many to try them all but i know that 0 16 brings errors.

I now know that for my application the default scanSettings value of 2 12 works fine. If you need more testing, just let me know.

giuliomoro

that's not how [delay] works: it takes a bang .

See below:

The maximum value for scan speed is 3, so 4 9 may not yield the desired result.

What I am trying to say is that if you do not updateBaseline after changing the bit depth to something other than the default 12, then I don't think that the differential values you get will be meaningful. Maybe if you go to a lower bit depth, the baseline will update automatically over a few sampling cycles, but if you go to a higher bit depth, it should require a manual update. If you run the Trill/general-settings example and open the GUI, you should be able to observe that behaviour.

Sharptone

Ok, that make sense. Thanks!