ac sensorizer with qt301

[fabricio]

this is a special message foe audiocommander but the topic can interessed other people.

Audiocommander have you tested the qt301 with the sensorizer cause  i have some problem with the stabilisation of the signal.

thanks

fab

[audiocommander]

Hi Fab,

Just tested this and I just had to increase the MIN value after auto-calibration to eliminate some jittering noise on the lower end.

I am having quite good results with these values (with LED on the qt circuit and enabled Release Detect (RLD):

- Q (Quantize to NoteLength): 32.

- MIN (Sense-Min): 23 | MAX (Sense-Max): 245

- F (Sense-Factor): 6 | SLW (Signal Slowdown): 0

- FRM (Scale From): 0 | TO (Scale To): 127

With these settings it's not processing any signals when idle, else from 0 to ~120 max

If this doesn't help you immediately, maybe these general hints will help to stabilize the signal:

- Make sure your QT301 is properly calibrated (Pins 7&8, see IC datasheet)

- Watch the cabling of the QT301 and see if your presence affects the sensorized values besides the desired approximation. You need to take special care of the wire to the touch-plate and of course the plate itself (QT pin 3)! Keep this cable short as possible, mind other cables & do not cross here, esp. try to get some distance between and/or use shielded cables. This cable works kind of like an antenna, so try to minimize this effect. There are also some hints in the datasheet about this.

- Just tested it with and without LED, works fine both ways

- ACSensorizer calibration (see Wiki Page, Step 13: automatic mode, maybe some manual finetuning later)

- Slowly increase the slowdown factor (SLW) (but keep it low to prevent too large gaps in the signal)

- Reduce "Q." to a lower note level, eg. for 8th or quarter notes

- Make sure unused AIN-pins are either clamped to ground or switched OFF, open pins will otherwise interfere

- Use the latest firmware (> 0.4.4. is okay, there has been a auto-calibration bug in < 0.4.3)

So, I hope this helps ;)

Best,

Michael

Edit: forgot to mention, that you should re-calibrate the qt301 after you hooked it up on the Sensorizer. This also improves the signal quality!