Timer with high accuracy 
Author Message
 Timer with high accuracy

VB5 experts,

I need to display something on the screen at very accurate timing. I am
not looking for very fast action but accurate. I have tried to use the
HiTimer control from mabry. The accuracy of that control is 1 ms but I
need microsecond accuracy. Any suggestion?

Haifang Li, Ph.D.
SUNY at Stony Brook



Tue, 28 Mar 2000 03:00:00 GMT  
 Timer with high accuracy

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Quote:

> VB5 experts,

> I need to display something on the screen at very accurate timing. I am
> not looking for very fast action but accurate. I have tried to use the
> HiTimer control from mabry. The accuracy of that control is 1 ms but I
> need microsecond accuracy. Any suggestion?

Try the OCX I attached. I tested it with graphics API's against timeGetTime
and GetTickCount and it seemed a lot more accurate. For more information on
the OCX see:
http://www.access.ch/discovery

I'm currently working on a program to display bitmaps and collect reaction
times. So tell me if you find some other solutions to your project, maybe I
can learn from you...

Regards:
Adrian

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Wed, 29 Mar 2000 03:00:00 GMT  
 Timer with high accuracy

On Fri, 10 Oct 1997 15:14:58 -0400, Haifang Li

Quote:

>VB5 experts,

>I need to display something on the screen at very accurate timing. I am
>not looking for very fast action but accurate. I have tried to use the
>HiTimer control from mabry. The accuracy of that control is 1 ms but I
>need microsecond accuracy. Any suggestion?

>Haifang Li, Ph.D.
>SUNY at Stony Brook


Are you running Windows - the environment that can run several apps at
one time - well effectively it can. The program that can go off and do
some disk trashing for what seems an eternity whenever it feels like
it?

In my oppinion you can forget that kind of accuracy. Even the 1mS
timer from Mabry misses events all over the place.

There are just  too many variables in the system to achieve accurate
timing events.

Regards,

Mike Floyd



Thu, 30 Mar 2000 03:00:00 GMT  
 Timer with high accuracy



Quote:
>In my oppinion you can forget that kind of accuracy. Even the 1mS
>timer from Mabry misses events all over the place.

Essentially you're right, it's not possible to guarantee any sort of
response time in Windows.  But we (Mabry) _do_ keep an accurate count
of how many milliseconds elapsed since we were last able to fire a
timer event and that count is available to the programmer.

Zane



Thu, 30 Mar 2000 03:00:00 GMT  
 Timer with high accuracy

Howdy!

You could try the GetTickCount API call, it's extremely accurate. It returns
the time since windows has started and continues counting, you could use
this to your advantage however.

Regards,
Shafayat Kamal
http://www.iessoft.com
Last updated: October 8, 1997

People who don't have time should make time.

Quote:
>>VB5 experts,

>>I need to display something on the screen at very accurate timing. I am
>>not looking for very fast action but accurate. I have tried to use the
>>HiTimer control from mabry. The accuracy of that control is 1 ms but I
>>need microsecond accuracy. Any suggestion?



Sun, 02 Apr 2000 03:00:00 GMT  
 Timer with high accuracy

Quote:

> VB5 experts,

> I need to display something on the screen at very accurate timing. I am
> not looking for very fast action but accurate. I have tried to use the
> HiTimer control from mabry. The accuracy of that control is 1 ms but I
> need microsecond accuracy. Any suggestion?

> Haifang Li, Ph.D.
> SUNY at Stony Brook


Look to the API calls to GetPerformanceCounter and
GetPerformanceFrequency.  They return a value that is a count of the
master osc.  If I remember my figures the frequency was about 1MHz
giving resolution in that range.

Of course you have the problem of windows response time, but this is the
most accurate way to get time intervals.
--
Jack Linder
Opinions expressed are not necessarily those of my employer.
Heck, I'm not even sure they're mine.
(when replying do not use the addreess your system sees.  I'm trying to
get rid of SPAM



Mon, 03 Apr 2000 03:00:00 GMT  
 
 [ 7 post ] 

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