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Subject: 
Re: Design wanted: Touch sensor for passing trains
Newsgroups: 
lugnet.robotics
Date: 
Wed, 29 Dec 1999 18:01:15 GMT
Original-From: 
Pete Sevcik <sevcik@flash.netANTISPAM>
Viewed: 
839 times
  
I have used a magnetic reed switch to detect trains.
Glue a small magnet to a lego piece, and mount on the train.  Cut a Lego wire in
half, and solder a reed switch to the cut end.
This detects the train with precision, and is not affected by shadows.  Also
costs a lot less.

     - pete.



Dave Baum wrote:

FWIW

I haven't tried this yet myself, but its very typical to use light sensors
for this sort of thing in HO scale model railroading.  There are a lot of
advantages to "contactless" detection.  On the down side, you need to
minimize interference from ambient light, etc.

Usually for HO scale stuff the IR LED and IR detector are separate pieces
(one on each side of the track).  This makes for a nice point-to-point
beam that gets interrupted by a passing car.

Some find this ugly, so another approach is to bury a passive light sensor
under the track pointing upwards.  A passing train will cause a shadow
over the sensor.

Dave Baum

In article <FnHCMC.KzF@lugnet.com>, "Carl M. Kadie" <carlk@msn.com> wrote:

I'm using Mindstorms to control Lego trains.

Does anyone have a design for using a touch sensor to detect a train
passing?

My intuition is that the touch sensor could be more reliable than the light
sensor (plus I have two touch sensors and only one light sensor).

Thanks much for any help,

Carl Kadie

--
reply to: dbaum at enteract dot com

--
Pete Sevcik     sevcik@flash.net
Techno-stuff Robotics
http://www.flash.net/~sevcik/
Robotics for FUN !



Message has 1 Reply:
  RE: Design wanted: Touch sensor for passing trains
 
What about hiding the reed switch in a small electrical brick (like a lighting brick) or a motor casing and hiding the magnet inside another brick? The pair could be a good replacement for the touch switch in imprecise applications like bumpers. -- (...) (25 years ago, 29-Dec-99, to lugnet.robotics)

Message is in Reply To:
  Re: Design wanted: Touch sensor for passing trains
 
FWIW I haven't tried this yet myself, but its very typical to use light sensors for this sort of thing in HO scale model railroading. There are a lot of advantages to "contactless" detection. On the down side, you need to minimize interference from (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)

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