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.
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.
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.
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.
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.
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!
There is an inexpensive commercial option that comes close, but does not fill all the requirements. Stanley tools: **broken link removed**
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.