Distance measurement

caveman

Hello to you all,
Any one can set me off in the right direction with my project.
I want to measure distances with my BS2 how do i get started.
second problem is measuring terrain level, measuring height, the height differences are not that big
like 20 cm tops.
Any exaples and www ref are welcome.
Thanks

Bruce Bates

Caveman -

Can you be a bit more specific about what you're trying to accomplish? What you've offered so far is a bit short on details, as well as being a bit vague.

There are infrared, sonar, laser, GPS and other solutions available, but each solution would be best suited to different specific needs.

Regards,

Bruce Bates

caveman

Thanks bruce,

here are some more details. What I try to accomplish is to make a vehicle, AGV type of thing that transmits terrain data to a PC

The terrain is a sand, indoor surrounded by concrete, wood·walls and a roof with dimentions of 60m wide, 100m long and 12m heigh.

What i need is feeld data sent to my pc, to make a computer model of the terrain, to calculate a trajectory the AGV then has to travel in combination whit a bildozer type of thing, to level the terrain.·

First i need to be able to detect the position according to the surrounding walls. Then make the vehicle trace the terrain (moving UP and Down the area) Then send the height data to the PC.· Finaly again via a new track coordinated by the PC for leveling.

Moving Up and down the area : parralel tracks separated by a defined distance by ref of the wall

Height : every defined travelled distance send pulse with meisured data.

Hope this gets you in to my fanthasy.

LoopyByteloose

Ultrasonics may do some of the initial survey work, possibly all of it. But, you have to control and know it's position and changes of position.

Parallax sells a Davantech SRF04 module that can identify barriers and opening over a wide range. (I think from about 6 inched to 10 feet, but their data is metric).

But, it seems to be a question of mounting it appropriately (a rotating platform and an azimuth servo) and possibly using a Mesmic Inclinometer or two with other servos to consistently level the platform.

Then in order to gather the kind of data you want you need to provide one or more 'beacon-like' reference points to work out all the angular mathmatics involved the actual contour. I suppose triangulaton of three points is optimal.

You may have to have a RF data link to your PC to do the number crunching from raw data quickly. Otherwise, the little BasicStamp robot would really be sitting still and analysing data a great deal of the time.

If your measuring platform is also you 'bull dozing' platform, it would likely have to stop work establish references, do measurements, and then return to work. Two separate devices would free the dozer to work one area while the survey device gathered data for additional work.

In the real world this is all done by a survey crew with laser survey tools. They presently attach a laser target system to control a grader or dozer's blade [noparse][[/noparse]within 1/10 of a foot]. Then the grader or dozer makes a straight run toward or away from the laser set up at grid of benchmarks. They may even have something that sweeps large curves (like turnpikes) now, but I was into this technology in about 1990 and our company just did level grading, not roadways or turnpikes.

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G. Herzog in Taiwan

caveman

Thanks Herzog

Ultrasonic sound for measurement looks OK but what about the elevation of the terrain, is this done by the beacons and triangulation of the meisurements.
I'll look up the doc. about the ultra sound gizmo you talked about.

thanks in advance

cabojoe

The Devantech sensor does metric or english units. Depends on what conversion factor you use.

caveman

Next transmitting data from PC to an BS2

any one has a sugestion?

cabojoe

http://www.parallax.com/detail.asp?product_id=30065· Surelink modules
http://www.parallax.com/detail.asp?product_id=30066· Quicklink modules
http://www.parallax.com/html_pages/resources/custapps/app_Boe-Dar.asp·· Boe-dar robotic mapping software

caveman

thanks cabojoe
lets try this first and see what it gives in reality