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Electronics => Electronics => Topic started by: h3ro on October 18, 2009, 04:36:10 AM

Title: IR range finder accuracy
Post by: h3ro on October 18, 2009, 04:36:10 AM
Hey,

I was wondering what the accuracy of a IR range finder is? How small changes can it notice? I tried doing a search here as I am sure someone must have asked that question before, but couldnt find anything.

The model I have is the same as this one:
http://www.robotshop.us/Images/big/en/solarbotics-i2c-it-ir-rangefinder.jpg (http://www.robotshop.us/Images/big/en/solarbotics-i2c-it-ir-rangefinder.jpg)
Title: Re: IR range finder accuracy
Post by: Soeren on October 18, 2009, 02:39:14 PM
Hi,

Since it's an IIC version with a one byte transfer on poll you have, the range (10..80 cm) will be divided up in 255 steps, but each step is NOT of the same magnitude - the longer the distance, the lower the resolution.

Accuracy, which isn't the same as resolution, determines the repeatability and will have some inter-device tolerance.

I haven't seen any hard data on that gathered on a scale to be statistically significant, but from your wording (accuracy vs. small change), it is unclear what you really wants to know.

Perhaps you could tell what you need, then perhaps we can find you a solution.
Title: Re: IR range finder accuracy
Post by: h3ro on October 28, 2009, 05:45:27 PM
What I am looking into doing is making my own very basic 3d scanning equipment. I have no plannes to try and scan very big or complex things, but it would be nice if I could get some ok results in the end. Right now I have a few IR range finders that is not used for anything and I was wondering if they could be used for this, or if they are not accurat enough.

If the IR range finder is not a good match for what I am trying to do, what kind of sensors do I need? I had a look at some of the laser range finders, but as you all probably know they are very expensive.

Regards,
Title: Re: IR range finder accuracy
Post by: Soeren on October 28, 2009, 07:42:52 PM
Hi,

Plenty of cheap 3D-scanners have been made with bits and pieces - check some of these pages:
http://www.google.dk/search?hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Ada%3Aofficial&hs=XMK&num=100&q=3d+scanning+laser+wine-glass&btnG=Search&aq=f&oq= (http://www.google.dk/search?hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Ada%3Aofficial&hs=XMK&num=100&q=3d+scanning+laser+wine-glass&btnG=Search&aq=f&oq=)