Dear David,

Thank you very much for your interesting to my last Email to Jeff. It is a
good question!

In electric equipment development, a large amount of cost appears not in
the electric components, rather in those "accessories" which seem not
important.

In my timer development, the price of the crucial components is $1.68AUD
for a Astable/Monostable Multivibrator (CD4047) and $1.23AUD for a Decade
Counters/Dividers (CD4017). But a container to protect the circuit cost me
more than $30AUD!!!

Also, the price of a compenent is not necessary proportional to its
importance. For example, in my timer system, a comparator costs $12.84AUD,
which is about 10 times as much as the cost of the main components I used.

The price I gave to Jeff is just a very rough estimation according to my
experience and my imagination of what kind of task Jeff will be involved.

Wish the above message can answer your question. Thank you very much.

Dong


At 11:32 10/10/00 +1000, you wrote:
>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
>> >
>> >---------------------------------------------------------------
>> >To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
>> >For information and archives: http://isb.ri.ccf.org/biomch-l
>> >---------------------------------------------------------------
>> >
>> >
>> //////////////////////////////////////////////////////
>> 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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>>
>
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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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