DPRG
DPRG List  



[DPRG] Contests at the Science Place

Subject: [DPRG] Contests at the Science Place
From: D. Daniel McGlothin ddm_dprg at yahoo.com
Date: Tue Feb 5 10:01:52 CST 2002

Consider a vertical orientation of the sensor's beam.

Also consider "begging" a light curtain from an industrial controls supplier
or manufacturer that would like the "exposure".

HTH,
Daniel

> -----Original Message-----
> From: dprglist-admin at dprg.org [mailto:dprglist-admin at dprg.org]On Behalf
> Of Ed Okerson
> Sent: Tuesday, 05 February 2002 10:49
> To: R. Bickle; 'Mike McCarty'
> Cc: DPRGlist at dprg.org
> Subject: Re: [DPRG] Contests at the Science Place
>
>
> Rick,
>
> I don't know if the 1/4" hole itself would cause a gap for IR detectors
> following the wall, but would the laser cause problems for IR
> detectors?  I
> would think it would swamp them and prevent them from seeing the IR signal
> they are looking for.  But your point about height also brings up a whole
> other topic, how high should the laser be?  If we put it 2" from
> the floor,
> and someone shows up with a 1" robot, we never detect it crossing
> the line.
> On the other hand if we put it 1/2" from the floor, we will likely get
> multiple triggers from tires going by and miss the robot body all
> together.
> I would really like to see this problem solved however.  It would
> really be
> nice to have 100% accurate timing for all the competitions.  It
> would also be
> cool to have the running clock that could be seen by all the spectators as
> the robot maneuvers around the course.  Maybe an array of beams 3
> or 4 high
> and at least 2 long.  As cheap as laser pointers are now days it should be
> easy to do.
>
> Ed Okerson
> President DPRG
>
> ----- Original Message -----
> From: "R. Bickle" <rbickle at swbell.net>
> To: "'Mike McCarty'" <jmccarty at SSD.usa.alcatel.com>; "'Ed Okerson'"
> <eokerson at fw.telenic.net>
> Cc: <DPRGlist at dprg.org>
> Sent: Tuesday, February 05, 2002 9:26 AM
> Subject: RE: [DPRG] Contests at the Science Place
>
>
> > Ed,
> >
> > Sure, this was more or less my default solution, but you would only be
> > sensing the passage of the robot at a given height. Some robots may have
> > pieces protruding back above or below the height of the lasers
> which would
> > change the time. Bill's little dragster robot comes to mind. It's rather
> low
> > to the ground. (And it has transparent wheels)
> >
> > What's the big deal about drilling holes in the walls? It would
> only take a
> > 1/4 inch hole or so to insert the emitters and detectors. I don't think
> that
> > this would interfere with the robots sensors.
> >
> > Rick
> >
> >
> > -----Original Message-----
> > From: dprglist-admin at dprg.org [mailto:dprglist-admin at dprg.org]On Behalf
> > Of Mike McCarty
> > Sent: Monday, February 04, 2002 9:37 PM
> > To: Ed Okerson
> > Cc: DPRGlist at dprg.org
> > Subject: Re: [DPRG] Contests at the Science Place
> >
> >
> > On Mon, 4 Feb 2002, Ed Okerson wrote:
> >
> > > Why?  All you need is two lasers, parallel to each other at the same
> > height
> > > with detectors on the other side of the course.  The real
> problem is how
> > to
> > > get the lasers across without drilling holes in the course
> walls.  I also
> > > suspect that lasers shining into the IR detectors will cause problems
> with
> > > many robots.  Most of our robots are probably not heavy
> enough to trigger
> > any
> > > pressure sensitive contacts.  I guess we could mount
> microphones at the
> > > corners of the course and do surface wave acoustic analysis to
> triangulate
> > > the bots position.  I saw this approach used once for very large touch
> > screen
> > > monitors that did not have any overlay on the CRT.
> > >
> > > Ed Okerson
> > > President DPRG
> > >
> > > ----- Original Message -----
> > > From: "Ralph Tenny" <rten at metronet.com>
> > > To: "R. Bickle" <rbickle at swbell.net>
> > > Cc: "'Rodent'" <daweasel at swbell.net>; <dprglist at dprg.org>
> > > Sent: Monday, February 04, 2002 7:04 PM
> > > Subject: RE: [DPRG] Contests at the Science Place
> > >
> > >
> > > > It is easy to detect when the front of the robot crosses
> the line; not
> > > > easy to detect when the back end crosses!
> > > > Ralph
> >
> > while (BeamSeen())
> >     DoNothing();
> >
> > do {
> >
> >     while (!BeamSeen())
> >         DoNothing();
> >
> >     ExitEpoch = GetEpoch();
> >
> > } while (BeamSeen() && GetEpoch()-ExitEpoch < MaxWaitTime);
> >
> >
> > ExitEpoch is the moment that the robot completely exited the arena.
> >
> > IOW, we wait until we can't see the beam. Then we wait until we can see
> > the beam. Then we "debounce" by forcing a wait until MaxWaitTime has
> > lapsed with the beam constantly visible. If the beam goes away again,
> > then we reset the timer. This way, if the beam sneaks through a hole in
> > the robot for a moment, it doesn't fool us into thinking that the entire
> > robot has gone by.
> >
> > Mike
> > --
> > char *p="char
> > *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
> > This message made from 100% recycled bits.
> > I can explain it for you, but I can't understand it for you.
> > I don't speak for Alcatel      <- They make me say that.
> >
> > _______________________________________________
> > DPRGlist mailing list
> > DPRGlist at dprg.org
> > http://nimon.ncc.com/mailman/listinfo/dprglist
> >
> > _______________________________________________
> > DPRGlist mailing list
> > DPRGlist at dprg.org
> > http://nimon.ncc.com/mailman/listinfo/dprglist
> >
>
> _______________________________________________
> DPRGlist mailing list
> DPRGlist at dprg.org
> http://nimon.ncc.com/mailman/listinfo/dprglist


_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com


More information about the DPRG mailing list