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laser distance measurement meter

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piyush_bhatt

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hello friends,

i want to build laser distance meter with following requirement. if anyone worked on that please help me out.

1 it should measure upto 100m
2 it must works 3 days continuously.
3 with cm acuracy.

thank you in advance.
 

keith1200rs

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Have you the skills to design such a circuit? If you work out the time it takes light to travel one centimetre the it will give you an idea of the sort of circuitry required. It is not a beginners task.

You need to be able to design optics and work with very small optical powers. You need to define your minimum distance as well.

Keith
 

bigdogguru

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Keith brings up a valid point, not to mention the budget required!

Come to think of it, someone has already designed and built a similar system using microwaves, its called Differential GPS.

Got any spare atomic clocks lying around?

---------- Post added at 08:58 ---------- Previous post was at 08:46 ----------

You may want to think about using ultrasonics.

Although, maximum distances of 100m with 1cm resolution would be challenging.
 

keith1200rs

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One snag with ultrasound is the wide angle. With lasers you can target a tree at a few hundred metres but with ultrasound you will most likely just measure to the nearest object.

Keith
 

bigdogguru

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True. I had my doubts as to the success of using ultrasonics; it was just a passing thought. The requirements as stipulated are very challenging using any method.
 

bigdogguru

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Interesting! Did you notice how they calculate movement?

When the receiver moves due to the motion of the part to which it is connected with respect to the reference laser line, the position of the laser beam on the optical target changes correspondingly. The electronics inside the receiver measure the centroid position of the laser beam on the optical target continuously and supply data on its x and y co-ordinates continuously to a PC computer, for example.
It would seem that measuring distance to a relatively stationary object would even be more challenging.
 
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keith1200rs

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The distance is measured simply by time of flight (although they do get mm accuracy!). You can find a lot of information about their circuitry from research papers and theses at the Olou university.

Keith
 

uxmanz

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Laser distance meter cannot be made via S=Vt equation ,...not that easy....
i was working on that project but abandoned because of many issues...like equipment cost .....put u to easy and tested way.... study this link...Webcam Based DIY Laser Rangefinder - Todd Danko



am sure it would help....to measure light u need atleast 1Ghz mips processor ...or use a high sensitive pin diode...of reading iR signal when laser hits the object....
any ways .....Todd Danko is easy way....use 2 web cams for more accuracy and a recursive filter like kalman ...any ways up to u!
 

jpanhalt

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There is an inexpensive commercial option that comes close, but does not fill all the requirements. Stanley tools: Stanley Hand Tools-77-930*

It has the range and precision, but does not run continuously. I have the low-end version (TLM100) and paid $50 for it new on ebay. Stanley engineers claim it is TOF. I did an experiment measuring distance through water. The apparent distance increases, which is consistent with it being TOF.

Anyway, perhaps the commercial version could be hacked to repetitively measure at its maximum duty cycle to get the job done with a lot less expense than trying to design from scratch.

John

*TOF = time of flight
 
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