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David Bastians
10-09-2000, 11:32 AM
Dear Dong,

I was interested to read your reply. Especially with regard to the
cost of the project. I have made timers based on a 555 IC, a few
latches (flip/flops), logic gates and a counter for a price of around
$20. There is really no limit to the potential number of triggers
(processed with a few logic gates) so I can't see why you'd ever need
to spend more.

David Bastians
Lecturer
School of Community Health: Physiotherapy
Charles Sturt University
Box 789
ALBURY 2640
ph:(02) 6051 6739, fax:(02) 6051 6727
mailto:dbastians@csu.edu.au


> -----Original Message-----
> From: Biomechanics and Movement Science listserver
> [mailto:BIOMCH-L@NIC.SURFNET.NL]On Behalf Of Dong CHEN
> Sent: Monday, 9 October 2000 10:21
> To: BIOMCH-L@NIC.SURFNET.NL
> Subject: Re: timers
>
>
> Dear Jeff,
>
> I developed a timer used to control the signal output one
> year ago. This
> small timer system can be controlled both manually and
> electronically. The
> basic idea of this timer development is to use a Monostable/Astable
> Multivibrator (CD4047) to generate a basic clock frequency;
> and use several
> Decade Counters/Dividers (CD4017) to get the timing accuracy
> you want. All
> manual or electric control, and input or output of the timer
> can be built
> up based on this basic structure of the timer. The cost (not
> include the
> labor) should be within $400USD.
>
> Also, it might be possible to use some kind of software
> package (LabView)
> combining with other I/O device to realise the function you
> need if you
> have these facilities. But, I have no experience of this approach.
>
> This info is just for your reference. Please don't hesitate
> to contact me
> if I could be of any further help.
>
> Cheers,
>
> Dong
>
>
> At 10:29 6/10/00 -0500, you wrote:
> >Biomech'ers
> >We are looking for simple digital timers/stopwatches that
> >can be controlled electronically or manually. For example, an
> >external electronic circuit with a manual switch or TTL signal
should
> >be able to stop and start the timer. We would also like to
> at some point
> >be able to hook up photoelectonic switches. These timers will
> >be used for reaction time and movement time studies as well as to
> >double check some of our timing data we gather from our kinematic
> >and kinetic instrumentation.
> >
> >The timer needs at least 1 ms precision and readouts. Layfayette
> >Instruments has such devices, but they are expensive (about
$600USD).
> >It seems to me that less expensive devices are available. I am not
> >against building a timer, as long as I can get the parts off
> the shelf
> >(e.g. RadioShack) and have easy instructions.
> >
> >Anyone have any suggestions?
> >--
> >Jeff Ives, Ph.D.
> >Dept. of Exercise & Sport Sciences Phone: 607-274-1751
> >Ithaca College Fax: 607-274-1943
> >Ithaca, NY 14850 USA Email: jives@ithaca.edu
> >
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> >---------------------------------------------------------------
> >
> >
> //////////////////////////////////////////////////////
> Dong CHEN
> PhD, MEng, BEng
>
> School of Physiotherapy
> Faculty of Health Sciences
> La Trobe University
> Bundoora, VIC 3082, AUSTRALIA
>
> Tel: +61 3 9479 5771; FAX: +61 3 9479 5768
> http://www.health.latrobe.edu.au/Health/Schools/PT/
> /////////////////////////////////////////////////////
>
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