RE: [Paddlewise] Electronic paddle - was bracing and power

Hi Peter,

No, I don't have anything to send BlueTooth to the device other than my
computer, which is not going paddling. The software will accept Bluetooth
input from a heart rate monitor, but only one model as it is interfaced to
it's output stream. I guess XML has not arrived on the scene yet. ;->  The
take-away point from that is if there were a BlueTooth data stream available
someone could write code to grab it an I would think log it along with the
accelerometer data.

Today I went looking and I have found several other free apps that will plot
and log the accelerometer data. One converts to m/s^2 and logs that value. I
can create a log with timestamps in ms from Jan 1, 1970 so it should be easy
to correlate multiple logs provided they have their clocks set the same
and/or as you suggest there is some sync pulse. It might work to strap the
device to the paddle shaft and swing the paddle around a couple times then
move the device to it's logging position for the trials.

Sadly, these later apps require post processing. I would like to have a
display that would give me instant feedback (that I could see in the
sunlight) of the effect of my strokes. I'm thinking that a ten second
integration might be good to allow me to alter some aspect of my stroke and
see what effect that has on the boat speed. The key is accuracy. GPS speed
is quick enough but not precise enough to know if the change is me or just
noise.

I think gathering the data is quite possible given these tools, and the
challenge will be knowing what data corresponds to what changes in form or
other application of the paddle to the water. There are two approaches that
might have merit for different purposes. Prerecorded instructions to the
paddler and live recording of paddler audio. I've tested both of these
techniques sitting here in my office and the device seems to handle both of
them just fine.

One thing I don't know, is if the logged values
are instantaneous acceleration values or averages for the time interval. If
it were averaged then it would be more useful for positional calculations,
but I expect it is instantaneous, and average acceleration will have to be
assumed, which is OK if the sample rate is high enough compared to the
acceleration of the vehicle.

The mp3 player comes with the device.

Here are links to the apps I'm looking at. No connection to any of them
other than I'm trying them out:

Auto mic gain audio recorder:
http://tapemachine.samalyse.com/

Accelerometer logs:
http://www.androlib.com/android.application.org-nargila-robostroke-android-app-jzCFp.aspx
http://www.androlib.com/android.application.pt-acoelhosantos-android-acc-nFwm.aspx
http://www.androlib.com/android.application.com-freshprogramming-sensortive-xDwB.aspx
http://www.androlib.com/android.application.com-ohisamallc-ohiapp29-jwDCF.aspx
http://www.androlib.com/android.application.abs-sensor-ADpA.aspx

I probably won't go paddling to try these ideas until Thursday (GMT -4) and
will continue to think about the issues and/or play with spreadsheets to
convert the data into speed values or other relative numbers that could be
used to compare techniques for better or for worse.

As in any other investigation, it's important to know what one is try to
achieve, and in my case I would like to know what is my most efficient
paddle stroke for A) steady state cruise, and B) burst acceleration.

Carey
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