Notices

this post is a duplicate from http://talk.maemo.org/showthread.php...88#post1038588 to keep the topics separate threads
[edit]as just turned out the N950 has same accelerometer chip as N900, this probably applies as well to M*6-harmattan and N950 (/N9 ?)

regarding the (double)tap_to_unlock thing:
I suggest to implement this separately in a generic way to have a system wide gesture detection daemon that has
-- configurable *attention*-triggers
. double-tap detected by accelerometer being one of them,
. various elementary gestures like e.g. face-down position or strong shaking another,
. and obviously some users would want button-press as trigger source.
-- Then the gesture-daemon needs some state awareness:
. state_is-locked,
. state_custom-script-returns-zero...
-- and needs to know which programs are in list of running processes aka started (ps ax) and also
-- which program is upfront and visible (or *would* be visible if the current program [lockscreen] vanished, i.e. second on window stack).

Depending on all these conditions met the daemon then starts to watch for certain gestures and does the configured action when sensing one of those gestures (e.g. send a dbus cmd to lockscreen app ::{ activation-trigger+=doubletap(X,1500,50);; conditions: triggerd-by=doubletap, gesture_to_detect=none, program_on_top=lockscreen;; action: cmd=dbus-send lockscreen "unlock"} )


I'd like to discuss the design rationales and architecture more in depth with anybody willing to give this a go

/j

[edit] would integrate like siamese twins with pocketsphinx voice detection as suggested in http://talk.maemo.org/showthread.php...t=pocketsphinx - voice input is "just another gesture" to detect

This would be great. However, does the digitizer still run even when the screen is powered off?

I assume face-down or shaking would be hang up/reject call. Double-tap while locked would obviously be to either wake the device up and enter the lock screen or to unlock the device to the running app/hildon-desktop.

You know what would be cool? If we put our finger over the proximity sensor while locked, and entered voice commands "call home" "update apt catalogs" "get gps fix" "get system temperature" and the like. We'd instantly bring the N900 straight into 2012.

NOTE: I do not know how to write code. I simply discuss on the forum, and occasionally make UI mockups.

My reference to doubletap was meant to exploit the accelerometer that has built in logic to do this, not the touchpanel on screen.
Of course there need to be other trigger sources as well, as e.g. proximity sensor which basically is one of the "buttons" from system's PoV.
And yes, digitizer aka touchpanel *should* be always-active as the technology is eating zero power while nobody touches the panel.
So your scenario is perfectly feasible once this daemon got implemented, with pocketsphinx integration.

cheers
jOERG

Wow! thats a very awesome idea! What about power consumption by such a deamn running full time?

I wish you the very best and lay down before you my tools of beta testing, constructive critisisms and idea-generation, good sir.

Depending on trigger source the power consumption should be next to zero.
E.g. the accelerometer has a built-in IRQ generator that engages a special hardware IRQ line even for doubletap - you can configure the parameters like time distance between taps, impact strength, and impact direction (snip against lower edge of device, tap on backside, etc). Unless this doubletap event gets detected by accelerometer, the whole system is as idle as it's been without the gesture daemon running.

Alas especially the accelerometer needs a kernel driver patch (http://talk.maemo.org/showpost.php?p...45&postcount=8) to make this doubletap thing work, so this might be restricted to powerkernel users.

Other sensors like switches/buttons, sliders (camdoor, kbd), proxy sensor, headset button, etc will usually work though, and should be equally humble about power consumption.

/j