N900 accelerometer has tap and double-tap recognition, but it seems that currently no software implements that feature.

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Can any N9 owner say if the double-tap works when:
1. double-tapping display with finger (should work, either way);
2. double-tapping display with non-conductive stylus (if yes, then accelerometer; if no, then touch-screen);
3. double-tapping body outside of display (if yes, then accelerometer; if no, then touch-screen);
4. double-touching the display softly (if no, then accelerometer; if yes, then touch-screen).

Alternatively, could you please point to Harmattan's wake-up-on-double-tap package, to see if it is port-able to N900 (in both software-open-source and hardware-applicability senses)?
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Thank you. Best wishes.
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Per aspera ad astra...