Jump to content

Recommended Posts

9 degrees of freedom.  Essentially 9 axes or traverses that can be sensed, such as rotation, translation or acceleration.

 

Yes, I understand the acronym. What are the axes?

Link to post
Share on other sites

I'm thinking that would be 9 sensors, but only 6DOF... after all, you can translate along all 3 axes, and rotate around all three axes... so six total... unless I'm missing something?

It's assuming you consider spatial acceleration as a separate DoF from translation, though that's something a physicist may take issue with.  By following that logic you could have 12DF by measuring the rotational acceleration too ;).  So I think it comes down to niche product jargon rather than standard scientific description.

Link to post
Share on other sites

TrackIR minus IR?

Hehe!  Could be!

 

You could use it for head movement, or as part of a virtual glove or controller.  It's more a technology demonstrator or DIY device than a polished consumer product, but it shows what's becoming possible.

Link to post
Share on other sites

So you could set the chip at it's "levels", attach it to any baseball cap for instance, and fly away? Seems a very useful tool for anybody that wants a basic head movement type of tool. Probably missing something, but is this device available?


Link to post
Share on other sites

I've no idea at what stage of development this controller is, but Arduino boards are normally used by hobbyists, i.e. they know a bit about electronics/programming and can assemble/customise/program the gear.  Without burning themselves on a soldering iron ;).  So I don't think it's a ready consumer item in the same way that TrackIR is.  There's no extra information with that video, but maybe digging through the Arduino site would reveal more?


 


It's most interesting to see what the tech can do, though, and you can bet that at some point it will find its way to consumer products.


Link to post
Share on other sites

Certainly not 9 DOF they only demonstrated 3 directions and in reality if your in cockpit that is all you need.  and you could potentially have 10 

Well, Degree of Freedom doesn't necessarily just mean direction - it refers to some variable that is not constrained by other variables in any system.  Hence it's very arguable that the derivatives of a function (velocity (f'), acceleration (f'')) can be separate DoFs than the function itself (position f=x).  In other words, the velocity at any point is not constrained by the position at that point, and acceleration is not constrained by velocity.  Similarly with rotation.  That's why statisticians and economists, for example, can refer to DoFs in the systems they analyse, which are nothing to do with physics.

  • Upvote 1
Link to post
Share on other sites

Looks like a pretty standard "9-DOF" sensor board like the one from Sparkfun here.  If you're that way inclined, you can use these with some neat Kalman filtering to create AHRS type applications that are sometimes used in RC aircraft and other purposes.  By 9 degrees of freedom (marketing guff, they're really 6-DOF), they're talking about the 9 measurements made - measuring rotation around the 3 axes measured absolutely (ie, differential from moment to moment) and 3 axes of rotation measured relatively (ie, measured against a fixed reference, in this case the earth's magnetic field,) plus linear acceleration in the three axes.  The demo video only seems to show the three rotational axes in use though...  You can buy a 3-DOF one for yourself (kit form or premade) from here - http://edtracker.org.uk/ although you'll need to become familiar with using OpenTrack and understand the limitations in getting it to work (ie- takes some cheating to get it to work with EZ-Dok.)


 


I've been messing around with these in Arduino projects for a while with a view to making a cheap AHRS system to use in my glider - commercially available systems cost upwards of $2k - but I haven't found a way to easily and reliably calibrate them and remove sensor drift in the field.


 


Cheers,


Derek


Link to post
Share on other sites

I've been messing around with these in Arduino projects for a while with a view to making a cheap AHRS system to use in my glider - commercially available systems cost upwards of $2k - but I haven't found a way to easily and reliably calibrate them and remove sensor drift in the field.

Would there be any mileage in using a sextant & compass to establish the Sun's position (or any daytime star/planet), and using that to reduce error in the system?  It would mean having to take a measurement, but in a bubble canopy that might be doable.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...