Computing stuff tied to the physical world

TK – Measuring distance

In Musings on Jun 14, 2012 at 00:01

Welcome to the Thursday Toolkit series, about tools for building Physical Computing projects.

Ehm, well, not quite :) … here’s how people defined and measured distances some 35 centuries ago:


It’s a stone, roughly 1 meter long, which can be found in the Istanbul Archaeology Museum. In more detail:

P5043851  Version 2

P5043851  Version 3

Not terribly convenient. I prefer something like this – have had one of them around here at JeeLabs for ages:

Screen Shot 2012 06 13 at 22 54 28

Then again, both of these measuring devices are quite a long shot (heh) from today’s laser rangefinders:

Screen Shot 2012 06 13 at 22 45 39

For about €82 at Conradno, I don’t have stock options, they are privately owned :) – you get these specs:

Screen Shot 2012 06 13 at 22 49 29

That’s 2 mm accuracy from 0.5 to 50 meters, i.e. one part in 25,000 (0.004%). Pretty amazing technology, considering that it’s based on measuring the time it takes a brief pulse to travel with (almost) the speed of light!

But you’ll need a 9V battery to make this thing work – everything needs electricity in today’s “modern” world.

  1. No!, it is not about “measuring the time it takes a brief pulse to travel with (almost) the speed of light”. This type of laser distance meters measures the phase difference between original laser pulse and reflected one. Resolution of 1mm gives you approximately ((3*10^8m/s)/2)/0.001m = 6.67 GHz of bandwidth. There is no way capture the light of so low intensity at this speed (almost). Look for info.

    • Ah, ok, I must admit I know nothing about how this thing works… thanks for the link!

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