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Pete Guest
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how to measure short distance <3mm |
Posted: Wed Dec 24, 2003 12:47 pm |
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hi,
Can someone help me, how to measure a short distance (less than 3mm) ? hope someone knows where to start.
Pete |
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mkent
Joined: 09 Sep 2003 Posts: 37 Location: TN, USA
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Posted: Wed Dec 24, 2003 5:57 pm |
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There are several methods. Do a search on LVDT (linear voltage differencial transformer) also try www.keyence.com They make optical devices. Bring a fat wallet. Merry Christmas and Great 2004 to all. Mick |
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Guest
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position sensing |
Posted: Tue Dec 30, 2003 1:29 pm |
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We make an educational object tracking system, mostly for teaching physics. But, it's based on video input so you can "zoom in" to measure small distances. You could look at our Website www.AlbertisWindow.com, or if you want to tell me more about your application I could give you a more specific reply. |
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Guest
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Posted: Tue Dec 30, 2003 2:20 pm |
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Try using a ruler .... or be more specific about your application ;-) |
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Mark
Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA
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Posted: Tue Dec 30, 2003 2:56 pm |
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A ruler wouldn't work! You would need a set of calipers. |
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SherpaDoug
Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA
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Posted: Tue Dec 30, 2003 3:49 pm |
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You might be able to use capacitance. It can be cheap and rugged, though it is usually used at <1mm. It depends on your budget and accuracy requirements.
Tell us more! _________________ The search for better is endless. Instead simply find very good and get the job done. |
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Hans Wedemeyer
Joined: 15 Sep 2003 Posts: 226
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IR |
Posted: Wed Dec 31, 2003 10:55 am |
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Look a the data sheet for the IR proximity detector I used in this design.
http://hans-w.com/RPM.gif
It is good for at least 3mm
If you scale the DC output with an op-amp then use the 10 bit ADC in the pic the resolution can be very good.
I also used the same sensor for a mouse button...
http://hans-w.com/Mouse_6.jpg
Happy new year... |
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Neutone
Joined: 08 Sep 2003 Posts: 839 Location: Houston
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Re: how to measure short distance <3mm |
Posted: Wed Dec 31, 2003 4:00 pm |
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Pete wrote: | hi,
Can someone help me, how to measure a short distance (less than 3mm) ? hope someone knows where to start.
Pete |
You can get analog hall effect sensors from Allegro that can be used to derive distance based on the change in flux density from a distance change in a magnets position. They might even have some application notes. |
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Guest
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Measuring Linear Displacement |
Posted: Mon Jan 05, 2004 2:48 am |
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Use a linear pot like a slider volume control from a radio (these are usually log taper, though.) 3 mm is really short. You may have resolution problems. Pots wear out and get noisy, too. |
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