 | | Design wanted: Touch sensor for passing trains —Carl M. Kadie
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| | | 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 (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Larry Pieniazek
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| | | | | (...) I don't have a design, but I do have a comment, to wit: With a touch sensor you are committing to a fixed dimension SOMEWHERE unless you get quite clever. It may be in the width of the vehicle, it may be in the height, it may be the depth of (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Dave Baum
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| | | | | 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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| | | | | | | Re: Design wanted: Touch sensor for passing trains —Pete Hardie
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| | | | | | | (...) hmmm. Why don't they just hide the sensor(s) in trackside terrain, like crossing gates, non-rolling stock, etc? (25 years ago, 29-Dec-99, to lugnet.robotics)
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| | | | | | | Re: Design wanted: Touch sensor for passing trains —Pete Sevcik
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| | | | | | 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 (...) (25 years ago, 29-Dec-99, to lugnet.robotics)
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| | | | | | | | RE: Design wanted: Touch sensor for passing trains —Russell C. Brown [RR-1]
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| | | | | | 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)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Daniel A. Segel
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| | | | | I've never actually done it myself, but if you're interested in building your own sensor you might want to look into using a reed switch. They detect magnetic fields, so if you put a small magnet at the head of the passing train in a place such that (...) (25 years ago, 29-Dec-99, to lugnet.robotics)
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| | | | | Re: Design wanted: Touch sensor for passing trains —James Powell
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| | | | | (...) My suggestion: Touch: Have the track elevated, and free to move up and down (1 'hinged' joint). Then have your touch sensor below the track. Light: Hard to get accurate, repeatable measurements. If light level changes, requires recalibration. (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | | | Re: Design wanted: Touch sensor for passing trains —James Brown
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| | | | | | (...) This would be my suggestion as well, if you want to use a touch sensor. If I recall correctly, they should be robust enough that the weight of the track won't set them off, but the weight of a passing train will. The only thing I'd worry about (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Guido Heunen
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| | | | | (...) Hi Carl, I tried some time ago, way before the mindstorms, to use read contacts. The magnets of the wagon/engines will close the contact each time they pass. I guess that the RCX can see this as 0 and 1. With this you can, I imagine, count the (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Carl M. Kadie
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| | | | | "Carl M. Kadie" <carlk@msn.com> wrote in message news:FnHCMC.KzF@lugnet.com... (...) Thanks for all the suggestions. I've refined my goals a bit: I'd like to use just Lego parts. I don't mind of the sensor is conspicuous. I don't mind modifying the (...) (25 years ago, 29-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | | | Re: Design wanted: Touch sensor for passing trains —Carl M. Kadie
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| | | | | | I've build the design from Ted Michon. It is working great. With Ted's permission, I've put his note on the web at (URL) to everyone, Carl (25 years ago, 31-Dec-99, to lugnet.robotics, lugnet.trains)
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| | | | | Re: Design wanted: Touch sensor for passing trains —Ted Michon
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| | | | Carl- We designed some that worked very well with the 4561 Railway Express sets that we used for the Orange County Festival of Trees earlier this month. The mechanism uses one of those 5 sided aircraft wing pieces held horizontally flat near the (...) (25 years ago, 30-Dec-99, to lugnet.robotics)
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