Subject:
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Re: "No Contact" Homebrew Train Sensor for Mindstorms
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Newsgroups:
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lugnet.trains, lugnet.robotics
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Date:
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Tue, 5 Dec 2000 21:25:59 GMT
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Viewed:
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1974 times
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At this point I don't have the sensor hooked to an RCX due to the fact that
Santa hasn't brought me one yet (hint hint Santa). I currently have the
sensor hooked into a Crestron Control system (http://www.crestron.com). The
sensor is hooked to a digital I/O port that monitors either a open or closed
event on the sensor. From what I've been able to find out, this would also
work for an RCX. After this December I will be trying this out and find out
for a fact if I am correct.
jt
In lugnet.trains, Steven Barile writes:
> James,
> Are they directly wired to the RCX or is there a resister in series. BTW
> where is the web page on the electrical specs of the RCX and home brew
> sensors? I can't remember.
> SteveB
>
> In lugnet.trains, James Trobaugh writes:
> > Chris,
> >
> > Another great little sensor for train detection, via Radio Shack, is the
> > little photo sensors they sell. I put them inside of a 2x4 technic plate and
> > then snap them face up on the track. This way they use the omni light from
> > the room as the light source, when the train crosses over the sensor the
> > light source is removed and the train's arrival is detected. By placing one
> > on both sides of the crossing you can tell if the train is still in the area
> > of the crossing. The basic logic is if either sensor is triggered lower the
> > gates, once both sensors are clear raise the arms back up.
> >
> > The only problem I had with this was at some of the shows I've done they
> > don't turn on the main lights till the show starts (i'm sure to save money),
> > and sometimes the sensors wouldn't work till the lights were all turned on.
> > Not a big deal, just that I couldn't test the sensors till show time. I did
> > start carrying a flash light for testing reasons though.
> >
> > Here are a few pictures of the sensors I've built:
> >
> > http://www.ngltc.org/novgats/image50.htm
> > http://www.brickshelf.com/cgi-bin/gallery.cgi?i=20391
> >
> >
> > In lugnet.trains, Chris Phillips writes:
> > > As has already been reported by others, I built an automated railroad
> > > crossing for the NELUG train display at last weekend's Greenberg show. I
> > > wanted to take a moment to describe the "homebrew" sensor that I used to
> > > detect an approaching train so that others might benefit in their own layouts.
> > >
> > > I originally tried several techniques to detect the presence of a train,
> > > including the touch sensor, the light sensor opposite a light source, and
> > > the good old infrared "radar" technique that has been well-documented on the
> > > robotics forum in the past. I also considered using Vision Command, but I
> > > didn't want to have a PC in the loop if I could avoid it. None of these
> > > techniques was very reliable: I couldn't find a good way to trip a touch
> > > sensor without derailing the train, and the other techniques required a lot
> > > of highly visible and unsightly "plumbing" somewhere along the track. I had
> > > pretty much abandoned the idea of using an RCX to detect a train before I
> > > remembered an idea that I had awhile back but never tried, due to my
> > > semi-irrational aversion to non-LEGO solutions.
> > >
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