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tensioned measure

 bleeping gizmo to allow building string lines to be used as tape measures
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A building string line is a string, placed under tension, to mark a plane or edge construction can be made to. They are the same a guide lines in drawing software.

The problem with string lines is they have to taut because a loose line will give an incorrect guide line. If taut, measurement marks can be placed on the string. Losing tension, means marks are lost. A re-tension will not give the marks back, until now.

If a cheap, bleeping force meter was placed in the string line, a tension could be redialed if lost. The laser level type bleep would indicate the correct tension. Probably a different frequency although the device wouldn't be on for long.

This would make moving string lines with marks a breeze.

I did think of a cheese wire alternative but it was a bit cutting edge.

Bonus feature - Anyone leaning a spade against the string line will have an embarrassing technological expletive.

—wjt, Apr 27 2017

An existing solution http://www.allenpre...asers-buying-guide/
If you have room for a taut string, then you have room for a laser beam. [Vernon, Apr 27 2017]

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       No need to bleep out your adjectives, [wjt]. We're all adults here. Say what you want.
—whatrock, Apr 27 2017
   

       You could make the string out of optical fiber and the sensor as a fiber Bragg grating. Actually, maybe you could put an FBG or other reflective element at each measurement mark, and measure the accuracy of the marks directly with OTDR.
—notexactly, Apr 27 2017
   

       [notexactly] I don't think optic fiber would handle the rugged situation especially one unsheathed to let the light out.   

       [Vernon] How do you put a multiple marks along the shot of the light beam? Light decaying extremely exponentially at a wanted distance has --hasn't-- been invented yet.   

       Lasers are common on building sites but don't do a storey pole's job. rather the initial marks. Notexactly is closer, this idea is more for a storey stringline that can be moved.
—wjt, Apr 28 2017
   

       //Light decaying extremely exponentially at a wanted distance has been invented...//   

       Presumably some kind of destructive interference. A fft of a square wave with the amplitude equal to the distance desired, driving a micro-pulsed multi-frequency laser array.
—pocmloc, Apr 28 2017
   

       If you have two lasers facing each other, firing micro-pulses in sync, then you would get dark spots where the pulses interfered. Adjust the timing and length of each pulse to adjust the positions of the dark spots. Add in other frequencies to compensate for the length of the darkness and the brightness.   

       If you shoot a beam of antiphotons does that count as dark light?
—pocmloc, Apr 28 2017
   

       Actually 300, 450, 600 and 900mm centres are desired so very dark and accurate spots would be welcome.   

       has / hasn't The mind races but the typing just can't compete. I suggest -- error change -- .
—wjt, Apr 29 2017
   


 

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