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 Robotics / 1934
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Subject: 
RE: Bumper Ideas Needed & Re: Positioning of 2 RCXs
Newsgroups: 
lugnet.robotics
Date: 
Wed, 30 Dec 1998 21:04:00 GMT
Original-From: 
Schott, Wayne W (MED) <WAYNE.SCHOTT@AMERMSX.stopspammersMED.GE.COM>
Viewed: 
1306 times
  
Dave,

I have another idea for a omnidirectional IR Transmitter/Receiver
arrangement.  It is based on the discovery I made with my
universal remote.  I can control my TV with my eyes as a
reflector (don't ask).

Try a shinny steel ball bearing, of about marble size, suspended
over the IR Transmitter/Receiver.  You'll probably have to experiment
with position to avoid blind spots.  It should have a fairly large
acceptance angle.  360 degrees around (X and Y) and probably at
least +/-35 degrees vertically (Z). You did say, you didn't want to
limit your thinking to only 2 dimensions.  This way the IR tower or
second robot can be higher or lower than the other.

If Maurice Hilarius is correct about white's reflectivity in the IR
spectrum, perhaps a white marble would work better.  I think
flat white may disperse the signal some what, gloss white might
be better, and it might explain why my eyes worked so well.

Off topic:
Does anyone have a suggestion for a type of glue to use on Lego
bricks?

Wayne W. Schott

----------
From: Cynthia E. Tsao[SMTP:cyndtsao@pacbell.net]
Sent: Wednesday, December 23, 1998 4:34 PM
To: Laurentino Martins
Subject: Re: Bumper Ideas Needed

I think the limitation is thinking in only two dimensions.

For a 360 sensor (albeit one that cannot tell which direction hit it), I
can concieve of a ring bumper suspended in the center over the robot.
The attachment is via a universal joint like apparatus.  When the bumper
collides with an object, it shifts off center, and takes pressure OFF of
a vertically mounted touch sensor.  Hard to describe, my ascii drawing
as follows will probably suck but here goes:

Side View:
               _______
              /   +   \ + is the 360 pivot, weight of the
             /    S    \ bumper structure keeps it centered on
            /    RCX    \ Sensor S, when one of the bumpers ( or )
           (    O   O    ) is hit, it pushes the + off center and
off of S, signal goes from 1 -> 0
NB:  O represents wheels, RCX is robot

Imagine a "Hat" like affair covering/surrounding the robot that is
balanced at a point under the top/inside of the hat.  I think that'll
work, but it'll be slightly cumbersome.

I have another idea for a omnidirectional IR Transmitter/Reciever
arrangement.  Create a robot chassis with the RCX oriented such that the
IR Port is pointing straight up.  Then construct a cone shaped reflector
to perch above the port with the point down (Probably use tin foil, I
know, this is cheating!).  Now, the IR signal 360.  See below:

Side View: \  / <- this is the reflector, signals get bounced
\/    down into the port coming in
    ^----- signals going up get bounced out sideways
IR
port

What do you think?  This way, several RCX units can communicate
regardless of rotational orientation on the XY plane.

Regards,
Dave Chen
dcchen@pacbell.net


----------
From: Maurice Hilarius[SMTP:maurice@harddata.com]
Sent: Wednesday, December 30, 1998 12:46 PM
To: John Huikku
Cc: lego-robotics@crynwr.com
Subject: Re: Positioning of 2 RCXs

With regards to your message at 10:25 AM 12-30-98 -0800, John Huikku.
Where
you stated:
Or apply aluminum foil to some blocks to make mirrors.

later,
john
Or paint them flat white.
A mirror, or tinfoil for that matter, is only about 40% to 60%
reflective.
A flat white surface is better than 75% reflective.


Cheers,

+--------------------------------------------------------+
| Maurice Hilarius           | The Past is History       |

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



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