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Subject: 
Re: Land mine robot
Newsgroups: 
lugnet.robotics
Date: 
Tue, 14 Jan 2003 03:38:24 GMT
Original-From: 
Steve Baker <SJBAKER1@AIRMAIL.NETihatespam>
Viewed: 
739 times
  
Scott Davis wrote:
I'm a Senior in high school and one of the requirements to graduate is that
we must complete a Senior project.  I know nothing about building sensors or
electronics at all.  All though I could learn very easily.  The purpose of
the post was to find something to use as mines and how to detect them.  I'm
just looking into a couple possible ideas before I commit myself to one
idea.

Since this is a school project - we shouldn't be telling you how to do it,
we should be pointing you towards ways to search for a solution yourself.

So...

This requires a logical approach (and that always looks good in a school
report!)

Now - your detector could be either active or passive.

An active sensor is like a sonar - that pings something
and detects the echo - a passive sensor detects something
emitted by the object.

If the mine has to be hidden beneath something (under a cloth might be
better than in something messy like sand), you have to look at the range
of penetrating waves/particles you could use to find the mine.  There aren't
really all that many to choose from

   Sound (and Ultrasound)
   X-Rays
   Radio waves
   Infra-Red
   Temperature
   Ultra-Violet
   Visible Light
   Magnetic Field
   Gravitational Field
   Electric Field
   Chemical Odor
   Radioactivity
   Mechanical Pressure (eg by touch)

...there are probably others I havn't thought of.

Now you can draw up a table of all the possible mechanisms
with two columns ACTIVE and PASSIVE - then look at each of
the couple of dozen possibilities that result.  Some you can
eliminate easily:  Detecting a mine by it's gravitational
field isn't going to work unless you plan on hiding some mini-black
holes!

You'll probably want to eliminate *most* of the 'passive' options
because mines are generally designed not to make themselves TOO
obvious (eg by glowing in the dark).

This table leads to some suprising possibilities!

You should end up with a short-list of half a dozen possible ways
to do this.

You might want to grab a copy of the Lego Dacta catalog:

     www.pitsco-LEGOeducation.com

...they have a bunch of 'DCP sensors' with an interface to the RCX.
These include voltage sensors, humidity sensors, air pressure, pH,
accellerometer, etc.  Unfortunately, they aren't cheap - $50 to $220!

There is also the standard Lego sensors - rotation, switch, light
and the temperature sensor.

---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1@airmail.net>    WorkEmail: <sjbaker@link.com>
HomePage : http://www.sjbaker.org
Projects : http://plib.sf.net    http://tuxaqfh.sf.net
            http://tuxkart.sf.net http://prettypoly.sf.net



Message has 1 Reply:
  Re: Land mine robot
 
(...) Or make your own. "Passive" sensors have a 5V constant current, and the raw value is the resistance, scaled so infinite resistance is 1023. "Active" sensors can draw more power, but I don't know anything about them. (22 years ago, 15-Jan-03, to lugnet.robotics)

Message is in Reply To:
  Re: Land mine robot
 
I'm a Senior in high school and one of the requirements to graduate is that we must complete a Senior project. I know nothing about building sensors or electronics at all. All though I could learn very easily. The purpose of the post was to find (...) (22 years ago, 14-Jan-03, to lugnet.robotics)

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