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webOS Development: AccelBall - A Practical Accelerometer Demo

Welcome, I’m glad it was helpful!

It would depend on what you’re doing, really. In this case, yes, because I’m not using the accelerometer data directly. It is simply used to adjust the “drift” variables which are what set the speed of the ball. Think in terms of, “last I knew, the phone was tilted this way, so I’m going to base my math off that to determine where the ball should move now.”

The animation occurs separately from the action of the accelerometer. With the code the way it is, if, for whatever reason, the accelerometer stopped giving the app data, the app would be stuck animating the ball with the last known acceleration. So you can update at whatever framerate you wish, it would simply require scaling the accelerometer data differently. But framerate and animation are another subject entirely!

The trick would be working out the math to suit your needs. With a little more time on the code it wouldn’t be too difficult to allow the ball to perfectly match the Newtonian physics we all know and love! But, often for games, that isn’t desirable and may make the game difficult to play. For applications where you’re tracking g-force, precision is key (and 4Hz is not enough).

On that end of things, there are ways to adjust the update frequency. With root permissions, simply set the value of “/sys/class/input/input5/poll_interval” to a higher value (specified in ms, as I recall). There was someone working on an extension to allow an app to set this explicitly, but it too requires root permissions to install, so this isn’t something which can be relied upon outside the homebrew community. I’ve got my fingers crossed that Palm allows apps to set a higher refresh down the line…at which point, I’ll likely write more on the subject.

Start going to town fiddling with the numbers and you’ll get a good idea of what’s going on. Adjust the scaling, the framerate, etc. and see what happens! That will cement the ideas far better than I can explain with words.

RE:ality - MIT to Give Us a "Sixth Sense" With Pico Projectors

Because usable and, more importantly, affordable pico projectors are here right now. The technology still translates to use on an HMD with little effort. It simply allows researchers who can not afford quality HMDs to do real work.

Not to mention group activities. There are no privacy concerns when you want other people to see the displayed information. Again, HMDs can do far more, but cost is always a factor. You only need one pico projector for a group versus individual displays for everyone in the case of HMDs.

Pico projectors could bridge a very important gap. Look at Bluetooth headsets for instance. No one wanted to wear them, it makes you look like a dork in most people’s eyes. There’s no way in hell you’re going to convince the general public that an HMD is worthwhile without first convincing them that the technology is worthwhile. Pico projectors are a less intrusive way to introduce the public to AR.

You don’t have to sell geeks on new tech, but for it to reach commodity levels so the price of hardware will drop, the public has to want it as well.

Interview With a Vam...an Entreprenuer

Heck yeah! I’m just glad I can pass some knowledge along to my bro!

By the way, you can login to my blog via facebook to post comments.

The Things I Think About... Manufacturing 2.0: The Economy And You

Hah, I hadn’t even noticed that the paragraphs had disappeared. Something must have happend on the backend when I was editing. I’ll get the paragraph breaks put back in!