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Velocity Sensitivity

Posted: Mon Mar 22, 2010 10:39 am
by Tom Munch
Is velocity sensitivity possible on the iPhone/iPod Touch/iPad screen? I think it would be really useful - especially on the drum samples. Maybe it could be measured by the relative size of the surface area in the tap - more surface area for a harder tap.

You get no information about

Posted: Mon Mar 22, 2010 1:51 pm
by Jesse
You get no information about the low-level details of the touchscreen from Apple's APIs unfortunately. I did some experiments with the accelerometer to do velocity sensitivity which worked OK, but the slight lag before getting that information about your hit was just too much to be really useful. I know there are some other apps out there that are claiming to do it, the one which interests me the most (don't recall the name) I think uses the sound from the mic input at the time of the impact to figure velocity... that could be promising.

If it's possible I'd so go

Posted: Mon Mar 22, 2010 3:07 pm
by Tom Munch
If it's possible I'd so go for it!

I have igog which is a drum

Posted: Mon Mar 22, 2010 10:51 pm
by Zappafrank
I have igog which is a drum app that can use the mic to trigger the drums thereby simulating velocity triggering, it works alright, more for novelty than functionality. Very tricky to be accurate with it.

Hi Guys, I'd also wondered

Posted: Sat May 14, 2011 3:37 am
by Howard
Hi Guys,

I'd also wondered about this fingerprint-size method for velocity. Interesting to learn the touchscreen doesn't provide enough info for it. Surprising too.

And yeah, as ZappaFrank mentions, iGOG is a velocity-sensitive drum app using mic input to sense tap velocity. It also uses mic input to trigger samples without tapping, just sounds or beatboxing. Pretty cool, but the drawback with using the mic is that ambient noise (i.e. other musicians) distorts the info, and possibly as well, playing with anything but headphones.

But thumbjam, as a compositional tool is more likely used with headphones than a single instrument app, so...

If only there were a way to tell the signature sound of a finger thump on the touchscreen, as opposed to most ambient sounds...

Does motion feedback have any new chance with the gyro in the Iphone 4?

I'd do anything to get velocity sensitivity...

Ratatadrums is sensing

Posted: Sat May 14, 2011 5:48 am
by mat
Ratatadrums is sensing velocity rather well without mic and gyro on my iPod touch 3rd gen.

The ambient noise can be

Posted: Sat May 14, 2011 2:22 pm
by caseyjamesbasichis
The ambient noise can be measured separately from the sound that occurs when the screen is touched. Unless the input is clipped or the ambient noise is very erratic the ratio should be pretty close. The audio spike from tapping the device is big and low.

It would seem to me with a little calibration between the audio and gyro it should be possible to grab a usable velocity even through the phone speakers.

I for one am no good at using the x-axis to control velocity. X great for large scale dynamic changes -- better than velocity, but from note to note, I have 20 years of experience using pressure to control dynamics.

I can't turn left.

I hear you. I'm never fully

Posted: Sun May 29, 2011 8:50 pm
by Howard
I hear you.

I'm never fully satisfied approaching velocity by position. A part of me stays mental, instead of in the creative flow. Though it does seem to be getting more comfortable with practice.

I also downloaded Ratatap Drums which Mat mentioned and with five mins of playing, it seems nicely designed, a little of the TJ experience for drummers. Not quite sure how they do the velocity thing tho...