Accelerometer in next hardware revision?

[Rene Mayrhofer]

Hi all,

Let me start my first post by saying thanks for initiating an open source 
mobile phone platform! 

My motivation for contributing stems from the background of ubiquitous 
computing and the possibility to use mobile phones for research in this area. 
Having an openmoko phone will be a huge benefit to research projects, and I 
am looking forward to laying hands on the first hardware version to support 
WLAN.

I would like to add to the existing wishlist item "Accelerometer" at 
http://wiki.openmoko.org/wiki/Wish_List_-_Hardware that there is probably 
many uses for it, e.g.:
- Detecting when the phone is being moved to the ear (this gesture is 
detectable) and reducing audio output to a certain maximum as a safety 
feature
- Switching on the LCD backlight based on gestures (like tilting it briefly)
- Gesture-based navigation in menus
- Switching display orientation (like the iPhone does it)
- A step counter (see Nokie 5500) and other sports uses
- Detecting motion in general and specific actions in particular (see e.g. 
http://architecture.mit.edu/house_n/documents/Bao03.pdf or 
http://www-static.cc.gatech.edu/~thad/p/031_20_Activity/pervasive04-lukowicz.pdf 
about combining accelerometers with microphones to improve recognition 
accuracy)
- or even secure pairing e.g. with a Bluetooth headset or other phones (sorry 
for the shameless plug here, but details can be found at 
http://www.mayrhofer.eu.org/downloads/publications/Pervasive2007-Shake-Well-Before-Use.pdf)
- and possibly many more...

Based on my own practical experience, 3D accelerometers are small, cheap, and 
power-efficient enough to integrate into almost any mobile device. We are 
currently using AMD ADXL330 accelerometers, which consume less than 200µA 
(see http://www.analog.com/UploadedFiles/Data_Sheets/ADXL330.pdf). If there 
is no ADC on board to sample it, then other accelerometers with SPI output 
could be used (e.g. the STM LIS3LV02DL with details at 
http://www.st.com/stonline/products/literature/ds/12094/lis3lv02dl.pdf). 
These of course consume more power, e.g. the STM up to 80mA.

If there is some interest in adding accelerometers, I would be happy to 
provide more details and/or try to get more colleagues with various special 
expertise involved.

PS: A laser pointer diode would also be very nice, with the same motivations 
(small, cheap, and power-efficient) and again some applicability for secure 
pairing (again, sorry for the plug: 
http://www.mayrhofer.eu.org/downloads/publications/WAIS2007-Laser-Authentication.pdf).

with best regards,
Rene
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