Accelerometers
 

Hello,

yesterday appeared a page on the maemo wiki about the accelerometers features in fremantle. In this page is suggested a example application, and a deb file (compiled to arm) is provided.

How should we use it ? :p or it's just for internal use/future code example ?

Since I'm very interested in the accelerometer features of fremantle, I have a couple of harmless questions (if this information can be disclosed now).

Is possible to set/get the sample rate and threshold via sysfs ?

The accelerometers d-bus code is OSS or will be ?

Thanks.

Re: Accelerometers
 

interesting

i wonder if we could hack something together using the wiimote drivers to give similar results.

tape wiimote to bottom of 810 and see if it works, or plugin one of the mini usb ones ive seen knocking about.
i doubt we could replicate the dbus part, but the sysfs portion looks feasible for a fake driver to supply.

Re: Accelerometers
 

I have compiled the app for X86 to test it in the SDK, but it fails with a nice core dump:

Re: Accelerometers
 

Might be best to look at the kernel code and see what the driver does (assuming we have the relevant bit), apparently the scaling, etc., to produce a value in milli-gs is done in there.

Re: Accelerometers
 

Yeah, the driver is there: /kernel-2.6.28/drivers/hwmon/lis3lv02d.c
But depends how the system use it :p

Re: Accelerometers
 

Ya know, if the next NIT has an accelerometer in it, I'm so gonna be stoked. That in itself has so many uses that I can't even name them all. :D

Re: Accelerometers
 

Hi, yes I published that page yesterday but then I went for other things and forgot to link it somewhere.

Basically is the best I could get to answer a question that was coming from the NumptyPhysics developer and others. Hopefully a better interface and documentation will come, but in the meantime you have the basics there.

About the little app, please contact marnanel directly. I'm sure he is willing to share his own findings but I don't expect him to be aware of this thread here. I have seen the app working but that's all I know about it.

Re: Accelerometers
 

In a Fremantle prototype device right ?

Thanks.

Re: Accelerometers
 

I was assuming the sysfs entry code would also be present. I can't look myself atm as I'm running on WinXP (can't apply the diff easily), but will have a look through later on.

Re: Accelerometers
 

Ah no worries, just looked in the patch. Take a look at the following file: /drivers/i2c/chips/lis302dl.c

Re: Accelerometers
 

Yeah, is there. Didn't looked for it :D. thanks !!!

Re: Accelerometers
 

In a development unit used to test Fremantle. Shaking my laptop with the Maemo 5 SDK installed won't work. ;)

Re: Accelerometers
 

So the answer is yes, you can alter the rate from the looks of it. See lis302dl_set_rate() and likewise the scaling with lis302dl_set_scale()

Re: Accelerometers
 

Humm, don't have that file, should have a different kernel, where did you grab yours ?

Re: Accelerometers
 

Ehehe, so we can't test it :)

Re: Accelerometers
 

I just grabbed the patch from the repo: http://repository.maemo.org/pool/fre...02+0m5.diff.gz

Re: Accelerometers
 

I can give feedback if anybody tries and uploads the packages to extras-devel.

Re: Accelerometers
 

Ah, almost everything is configurable, nice work.
I'm happy now :D

Re: Accelerometers
 

That's actually not as a strange idea as it seems. The tiltstick e.g. just works inside the sdk and so would any other usb peripheral connected via usb and accessed via libusb.

Re: Accelerometers
 

does the tiltstick use the same format and sysfs entries as the built in commands?

if not, it would be nice if there was perhaps a small redirection app which could allow people to test using as you say a tiltstick, or using a bluetooth connected wiimote.

Perhaps the library version does this already and will accept input from any accel unit, maybe someone else will know.

Re: Accelerometers
 

No, it doesn't. But the page now says that there'll perhaps be a library.

Re: Accelerometers
 

The enigma game is now in fremantle extras-devel and includes accelerometer support.

Re: Accelerometers
 

And works in a real device with great precision! I benchmarked yesterday with a device and 2 users without NDA: my 2 and 4 year old kids. It was the first time they played anything like this and they did move the device naturally based on their knowledge on real gravity. They even got through the levels 1 and 2!

My big son asked me whether that was a real ball.

Re: Accelerometers
 

It amazing how kids perceive the world at that age, makes you wonder what we can learn from them :)

Re: Accelerometers
 

How enigma is using the accelerometer? Is it using it through libtiltstick?

Accelerometer really needs some documentation. The wiki page doesn't count as documentation atm :)

Re: Accelerometers
 

Indeed, I've got a great idea for a simple app using the accelerometers; but am unsure whether it's best to poll the sysfs interface directly, or some other mechanism.

Re: Accelerometers
 

Please file a bug for the lack of official documentation on how to use the accelerometers. I put together the wiki page as a temporary solution.

Re: Accelerometers
 

https://bugs.maemo.org/show_bug.cgi?id=4724

Feel free to add more specific requests on the documentation that should be provided.

Re: Accelerometers
 

Never played with an iPhone or Wii have they? My 3 year old cousin loves to play that ball game on his dad's iPhone...

Re: Accelerometers
 

Nope, i just polls the sysfs. I completely removed tiltstick support as only 2 or 3 devices ever had the necessary hardware.

But i agree that some generic tilt sensor solution is required which may then again include support for the tiltstick.

Re: Accelerometers
 

Apropos accm, I undestand this is a hardcore question but... will we have access to the inertial wakeup feature of the chip ? (this could be used to detect being picked up/flipping pages/etc without polling like crazy).

Re: Accelerometers
 

many laptop hard drives have accelerometers built in to sense falling/dropping.. maybe you could use that?

Re: Accelerometers
 

There is a new version of NumptyPhysics in Fremantle extras-devel. The game now starts with a new but provisional screen: "Accelerometers test".

Sadly the test fails. The objects in that screen and anthing else you draw follows the same gravity falling down the display... no matter in what position you have the device. Maybe someone can give a hand to Tim Edmonds?

Re: Accelerometers
 

I uploaded madbomber 0.2.5-3maemo5 to extras-devel, it has accelerometer based control now. Any feedback (does it work, direction ok, general feel) would be welcome so I could decide what do with it.

Re: Accelerometers
 

MadBomer doesn't seem to respond to accelerometers. The keys do work.

Re: Accelerometers
 

Doh! I left my acceleremoter test setup in the code (which is typing some numbers manually to a file and see what happens). You could try this

Re: Accelerometers
 

Bringing this back from the dead...

I looked at sandcastle and there is the DBusGProxy callback. Ok, what amound of motion does it take to trigger such a callback?

Is there some documentation on the nature of the dbus accelerometer functionality?

Re: Accelerometers
 

hi,

i am also interested to know how one can access the accelerometer on the N900, especially if it is possible to do so via Python.

how about other sensors? or radio signal/base station/battery etc.?

thank you..

wahlau.

Re: Accelerometers
 

See http://wiki.maemo.org/Accelerometers, it even has a python example.

Re: Accelerometers
 

thanks. that answers my answer pretty well!

i wonder if there will be Sensor API-like on the S60 Platform interfaces on N900. that would make many things simpler... :)