[time-nuts] GPS->audio interface

Lux, James P james.p.lux at jpl.nasa.gov
Sun May 10 22:56:49 UTC 2009




On 5/10/09 12:10 PM, "Hal Murray" <hmurray at megapathdsl.net> wrote:

> 
> 
>> As a model for what they're trying to do, say you were going to
>> measure the acceleration due to gravity by videotaping a falling
>> object against a scale in the background. Except that the motion is
>> more complex.. Maybe imagine putting an accelerometer in the "payload"
>> of a trebuchet... And you want to time align the position of the
>> trebuchet components (from the video) with the forces on the payload.
>> That's not what they're doing, but now that I describe it, that WOULD
>> be a cool science project.  And get away from the "here, I built a
>> trebuchet and launched a projectile X meters" which is kind of tired.
>> (get one of those analog devices 3 axis accelerometers, hook it to a
>> suitable datalogger..)
> 
> For something like that, you could:
>   start the camera
>   start the recorder in the payload
>   whack the payload with a stick to inject a calibration marker
>     (the stick has to be visible in the camera)
>   maybe re-aim the camera
>   launch the payload...
> 
> 
> 
Yes.. This is called a "slate" or "clapper board" in the movie trade.




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