Subject:
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Re: lasers and RCX
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 9 Jun 2002 15:07:12 GMT
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Viewed:
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555 times
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Hi, Dan
I remember that thread. But I don't remember anything concrete about that. I
started a small project of mine at the time based on that.
I have an sugestion for you. Focus on the problem, not the solution. What do
you want to do exactly? Signaling? Proximity sensing? Anything else?
For example, people used IR and sound based sensors for proximity sensing
with success. One of these guys send a lego style proximity sensor in the
web.
The point is: laser may not be the best solution for your problem.
I will describe you my old project.
My objective was simple. At least the idea. I wanted to set a navigate
system for the robot at home. I would put some beacons at key points at home
since the robot could use them to check his position by triangulation and
correct its course.
Since I wanted it to be simple, the beacons were passive. The idea was to
use reflective beacons. That way they could reflect the beacon back to the
robot.
I used some tubes (any plastic cosmectics recipient fits) covered with an
aluminium sheet for reflection. I thought about other types but I never
tried.
The robot would have a rotating tower with a laser pointer and a lego light
sensor that would scan for a reflection.
I never made it work well but I confess I didn't dedicated enough time to
that and I quit early.
The main problem is that the laser is strong only while it is a focused
beam. After reflection with an aluminium paper it turns in a difuse blur.
the good point is that you can hit the lego sensor easily that way. The bad
part is that the light sensor could not detect this weak reflection unless
it was very close.
You could try other kind of sensor more sensitive to the wavelenght of your
laser. In my case I was restricted to lego parts due to time.
Another aproach would be to try a better beacon to reflect the beam, not a
blur. In theory a good mirror would do that. For practical purposes you
would need a non planar reflective surface. Your tower would need to tilt
the laser beam up and down a bit also. That complicates the robot tower a
bit. You would also need to build a proper beacon. Peharps a cilindrical
structure with a reflective surface and a side profile like this:
* *
**
**
* *
Building this kind of beacon was beyond my hand skills.
In fact, I decided to change my nav system by an entirely diferent aproach
without lasers, but that is another story...
best regards,
Mauro Vianna
Dan Novy <lego-robotics@crynwr.com> wrote in message
news:3CFE3A33.D702FD7B@flashfilmworks.com...
> Years ago, there was a thread about hooking up lasers to the RCX and
> using then for signaling and proximity sensing. Aside from the dire
> warnings (Don't blind the cat!), does anybody remember this thread?
> I've recently come into ownership of a few hundred cheap 1.5 volt lasers
> and was wondering if anybody has any cool projects with the RCX and low
> power lasers. Links would be lovely.
>
> --
> Dan Novy
> Visual Effects Technical Supervisor
> Flash Film Works
> dan@flashfilmworks.com
>
> /////////////////////////////////////
>
> Windows Free by 2003!!!!!
>
> /////////////////////////////////////
>
>
>
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Message has 1 Reply:
 | | Navigation using landmarks (Was: Re: lasers and RCX)
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| (...) I've played quite a bit with this kind of problem (although I put the reflector on the robot and the laser in the corner of the room - but that's another story). What's needed is a "RetroReflector" - which is to say, an object that always (...) (22 years ago, 11-Jun-02, to lugnet.robotics)
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Message is in Reply To:
| | lasers and RCX
|
| Years ago, there was a thread about hooking up lasers to the RCX and using then for signaling and proximity sensing. Aside from the dire warnings (Don't blind the cat!), does anybody remember this thread? I've recently come into ownership of a few (...) (22 years ago, 5-Jun-02, to lugnet.robotics)
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