Electronic Distance Measurement

[Kevin C.]

I'm looking for some information on the precision/accuracy of
infrared, laser, and ultrasonic sensors.

In one application, I'm looking to measure a distance 50-70 inches
to an accuracy of 1/16".

In a second application I'm looking to measure a distance of 0-8"
to within 0.005" This is very similar to what "digital calipers"
are capable of, but I'm curious as to how they work.

Any help/ideas/pointers are appreciated.

Kevin

 

[Robert Baer]

I'm looking for some information on the precision/accuracy of
infrared, laser, and ultrasonic sensors.

In one application, I'm looking to measure a distance 50-70 inches
to an accuracy of 1/16".

In a second application I'm looking to measure a distance of 0-8"
to within 0.005" This is very similar to what "digital calipers"
are capable of, but I'm curious as to how they work.

Any help/ideas/pointers are appreciated.

Kevin

Start with the accuracy as defining the longest wavelength and i would
think divide by four. Determine the lowest frequency needed based on the
method (RF or sound).
Next, take the shortest range as defining (half of the) the travel
time based on the method (RF or sound). Again, i would think divide by
four.
With these number pairs, one method would most likely stand out as
being the most practical with parts and expertise on hand.

 

[Pelin]

I'm looking for some information on the precision/accuracy of
infrared, laser, and ultrasonic sensors.

In one application, I'm looking to measure a distance 50-70 inches
to an accuracy of 1/16".

In a second application I'm looking to measure a distance of 0-8"
to within 0.005" This is very similar to what "digital calipers"
are capable of, but I'm curious as to how they work.

Any help/ideas/pointers are appreciated.

Kevin

Try searching for laser sound surveillance equipment, which picks up
vibrations of the glass window and transforms it to sound. Basically it
measures distance with such resolution that you require.

 

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Try searching for laser sound surveillance equipment, which picks up
vibrations of the glass window and transforms it to sound. Basically it
measures distance with such resolution that you require.

These devices don't measure absolute distance.