gbulmer
Moderator
poslathian - what's the problem?
The estimate was an upper bound of 5000m/second
http://www.engineeringtoolbox.com/sound-speed-solids-d_713.html
So 1cm =~ 0.2us
A friend measures laser pulse times to much better than 100 picoseconds with a reasonably normal FPGA and PIC32, so I imagine Oak should be able to handle sound through a solid to 1cm.
poslathian
LeafLabs
The problem was in the plate i was using, which was kind of a thin but hard cardboard thing (back of a large mirror) that was really rather resonant and had a hard rim.
The signal, if you amplified it with a gain of about 1000, was clearly visible on the scope, but very difficult to actually filter in such a way as to extract the phase information. The reason its difficult is because you dont get one nice pulse, you get lets of pulses - reflections and resonances and so forth. You must extract the *first* pulse from both sensors to be consistent, which is hard to do, since its often super small.
Its not an impossible problem, just the material I was using made everything quite difficult.
man, it's really a shame that amazon gobbled up touchco and hasn't done anything with the tech yet. their touchpads did all that sensing magic for you (they were basically one giant interpolating force sensing resistor)..
hopefully we'll see them in the next kindle, and hopefully they'll be hackable.
poslathian
LeafLabs
Im confident with the right material the piezo sensor triangulation scheme can be made to work. But it is always nice when fancy gadgets you couldnt make yourself are hackable.
Anyone going after the $2k bounty for open source drivers for the kinect (offered by ladyada)?
I remember paying 10 grand for one of those rangefinding cameras about 4 years ago, now theres almost an identical sensor baked into the kinect which is only $150!
gbulmer
Moderator
poslathian - there is quite a lot of discussion about the difficulty of cracking kinect, and also whether most of the work is being done on the XBox anyway:
http://www.adafruit.com/blog/2010/11/04/the-open-kinect-project-the-ok-prize-get-1000-bounty-for-kinect-for-xbox-360-open-source-drivers/
the post "Comment by mark — November 5, 2010 @ 2:09 pm" sounded quite plausible.
If most of the work is on the XBox, then we are waiting for Oak (or whatever I can do with a PSoc 5 :-)
You must log in to post.
