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joseph hollinger
Joined: 12 Sep 2002
Posts: 9536
Location: United States, California, san francisco
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 Posted: Sun Jan 31, 2010 9:47 am Post subject: Re: For the rest of us... |
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| Steve Kay wrote: | I know having a laptop application is the ultimate, but if you're not into programming its a bit intimidating. Since I'm pretty good with a calculator or Excel, I just bought these.
http://www.imarketcity.com/wewxt150lbdi.html
The output boxes have Velcro on the back so mounting them to a clip-board when laid out is simple. |
Have you checked to see if they have a serial output port? Lots of scales do, so that they can be used with UPS/USPS/Fedex shipping programs.
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Steve Kay
Joined: 04 Nov 2009
Posts: 190
Location: United States, New York, Greenlawn
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| Posted: Sun Jan 31, 2010 10:09 am Post subject: Serial port |
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No they don't. They just have an input for the 9V transformer for AC power.
Not even a connector between the display and scale. I work in aerospace and I'm sure my data aquisition guys could work that out, but that was exactly what I wanted to avoid. The scales are very repeatable and sensitive. They're made in China and inexpensive but very nicely made. |
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joseph hollinger
Joined: 12 Sep 2002
Posts: 9536
Location: United States, California, san francisco
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| Posted: Sun Jan 31, 2010 12:35 pm Post subject: Re: Serial port |
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| Steve Kay wrote: | No they don't. They just have an input for the 9V transformer for AC power.
Not even a connector between the display and scale. I work in aerospace and I'm sure my data aquisition guys could work that out, but that was exactly what I wanted to avoid. The scales are very repeatable and sensitive. They're made in China and inexpensive but very nicely made. |
Sounds like a good setup.
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joseph hollinger
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Chris Reinhardt
Joined: 29 Aug 2002
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Location: United States, New York, Ossining
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5795
Location: United States, California, Winnetka
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| Posted: Thu Feb 04, 2010 9:40 am Post subject: |
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I always wonder how accurate those are at the light loads we use. I know it says 1% but is that really across the entire scale  ?
Mike G.
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Chris Reinhardt
Joined: 29 Aug 2002
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Location: United States, New York, Ossining
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| Posted: Thu Feb 04, 2010 12:22 pm Post subject: |
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How accurate is a $9.99 bathroom scale? How accurate is a $90 Chinese made scale? I guess you could hop on there and see if it reads the same on each scale???
Constancy is what I would look for.
CR |
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joseph hollinger
Joined: 12 Sep 2002
Posts: 9536
Location: United States, California, san francisco
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| Posted: Thu Feb 04, 2010 1:01 pm Post subject: |
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| Chris Reinhardt wrote: | How accurate is a $9.99 bathroom scale? How accurate is a $90 Chinese made scale? I guess you could hop on there and see if it reads the same on each scale???
Constancy is what I would look for.
CR |
I stack my scales one on top of each other. Once they are stacked, each scale is zeroed. Add a weight to the top and they should all read exactly the same. Three of my four do this. The other is off by 0.1 pound.
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Chris Reinhardt
Joined: 29 Aug 2002
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Location: United States, New York, Ossining
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| Posted: Thu Feb 04, 2010 1:27 pm Post subject: |
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| joseph hollinger wrote: | | I stack my scales one on top of each other. Once they are stacked, each scale is zeroed. Add a weight to the top and they should all read exactly the same. Three of my four do this. The other is off by 0.1 pound. |
OK, but that defeats the purpose??? The bottom scale in reality has a greater weight on it, and the the top scale has the least, regardless of how they are zeroed. So they read the same but in different ranges, might be the reason one of the scales are off. Zero the scales by themselves and use that same weight on each, see if the results are the same. Also the resolution may be set at .1, so if it's between .06 and .15 it may flip either way.
CR |
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joseph hollinger
Joined: 12 Sep 2002
Posts: 9536
Location: United States, California, san francisco
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| Posted: Thu Feb 04, 2010 1:31 pm Post subject: |
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| Chris Reinhardt wrote: | | joseph hollinger wrote: | | I stack my scales one on top of each other. Once they are stacked, each scale is zeroed. Add a weight to the top and they should all read exactly the same. Three of my four do this. The other is off by 0.1 pound. |
OK, but that defeats the purpose??? The bottom scale in reality has a greater weight on it, and the the top scale has the least, regardless of how they are zeroed. So they read the same but in different ranges, might be the reason one of the scales are off. Zero the scales by themselves and use that same weight on each, see if the results are the same. Also the resolution may be set at .1, so if it's between .06 and .15 it may flip either way.
CR |
The idea is that you are adding a random amount + a known amount to each scale. For them all to read the same (in effect) is statistically unlikely. And they read the same no matter what order you stack them in 
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Steve Kay
Joined: 04 Nov 2009
Posts: 190
Location: United States, New York, Greenlawn
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| Posted: Tue Feb 09, 2010 10:10 am Post subject: CG Height |
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Guys,
I built a spreadsheet to do the CG height location. Problem is i dont know how to send it to you guys as an attachment. Tell me how
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5795
Location: United States, California, Winnetka
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| Posted: Tue Feb 09, 2010 10:36 am Post subject: |
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| joseph hollinger wrote: | | The other is off by 0.1 pound. |
Dude your kart setup will never be right on now!
Mike G.
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joseph hollinger
Joined: 12 Sep 2002
Posts: 9536
Location: United States, California, san francisco
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| Posted: Tue Feb 09, 2010 11:28 am Post subject: Re: CG Height |
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| Steve Kay wrote: | Guys,
I built a spreadsheet to do the CG height location. Problem is i dont know how to send it to you guys as an attachment. Tell me how |
You can put online at some place like mediafire.com, or you can email it to me and I'll do it for you.
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Steve Kay
Joined: 04 Nov 2009
Posts: 190
Location: United States, New York, Greenlawn
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| Posted: Tue Feb 09, 2010 3:45 pm Post subject: C of G Height Calculator |
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C of G Height Calculator
Here's the calculator. Joseph, perhaps you can integrate it for the guys with serial output scales. I'm not sure exactly what the benefit of CG height would be in set-up, but I'm sure one of us will see how the weight transfer (lateral G's) will let us measure track grip. C of G height is not an easily changed variable.
http://www.mediafire.com/?zzqwmtnmib1
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Steve Kay
Joined: 04 Nov 2009
Posts: 190
Location: United States, New York, Greenlawn
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| Posted: Wed Feb 10, 2010 6:58 am Post subject: C of G |
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I fixed the link from last night if you tried and it failed.
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