[time-nuts] Need usb time interval time for portable bullet chrongraph
info at blackmountainforge.com
Mon Aug 27 16:15:45 UTC 2012
USB is a serial protocol and has some latency issues.
I am also involved with CNC machining and this has caused some issues in the
past. (the 'standard' is to use a parallel port or two)
The work around is to offload the timekeeping functions to an external box
and just use the USB to transfer data. Your chrony could store the times and
then transfer the session data to the 'puter through the USB port.
> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Don Latham
> Sent: Sunday, August 26, 2012 22:52
> To: Paul Cianciolo; Discussion of precise time and frequency
> Subject: Re: [time-nuts] Need usb time interval time for
> portable bullet chrongraph
> Hi Paul:
> I'm presently adapting a chrony chronograph because I want to use the
> triggers for timing and other purposes. They've spent a LOT of
> engineering time to get proper triggering, and the triggers can easily
> be pulled off without disturbing the basic unit. The triggers
> are robust
> and will drive a piece of coax with a nice pulse at a 5 v level. The
> cheapest chrony is under $100 and using their triggers will save you
> HOURS and HOURS of fiddling around, trust me!
> You can use something like an arduino which has two interrupt
> inputs to
> do the time measurement, or as Tom suggests.
> Paul Cianciolo
> > Hello Folks
> > I have been looking at bullet chrographs and wondering if I
> could get
> > the a usb module to do a interval measurement and display
> on my laptop.
> > on a yet to be discovered module to calculate the time
> interval between
> > the pulses?
> > The bullet travels at approx 1050 feet per second.
> > By spacing my gates providing the start stop pulses precisely 1 foot
> > apart I think a direct read out except for the decibal
> point being in
> > the wrong place .
> > Does this seem fesable?
> > Here is one module I found
> > Any thoughts on this?
> > The reason for the USB would be for display on my laptop at
> the firing
> > range
> > Thank you for any help I would really appreciate it
> > PaulC
> > W1VLF
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