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What the heck are they called? I know the whole thing is referred to as a grade crossing, but other than crossbucks, I don't know what to call it. Anyways, I cooked this up recently: (3 URLs) It's going to be part of a larger module with a road (...) (20 years ago, 16-Dec-04, to lugnet.trains, FTX)
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| | Re: Grade Crossing Signal Thingy...
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(...) sweet. that's one of the better solutions i've seen for this. i think it was the ltc from georga that had the automated grade crossing at brickfest 2003. from what i remember it was very relyable and worked with magnents and a light sensor. (...) (20 years ago, 16-Dec-04, to lugnet.trains, FTX)
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| | Re: Grade Crossing Signal Thingy...
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(...) The red/white bar is called the crossing gate I think. I don't think there are any fancy/complicated names for the parts. (...) I think it was not NGLTC, but rather GFLTC, specifically Robin Werner's work. I think Robin put up a link to info (...) (20 years ago, 16-Dec-04, to lugnet.trains, FTX)
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| | Re: Grade Crossing Signal Thingy...
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Anyone have any tips on programming the crossing so it works (...) Yes, go with magnets! :) I put my programme in the RCX 3 times, each time changing the light sensor to a higher setting. It worked great the 1st time in a shopping mall, but our (...) (20 years ago, 16-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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Magnets, righto. How do I do that? I've spent most of today trying to put together a program for a pressure pad triggered setup, haven't had any sucess. Same with a light program. I don't have any idea how to use magnets. Do you have a program I (...) (20 years ago, 16-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) You'll need more than a program, you'll need to make sensors of some sort, as sensors that detect magnets are not on offer from LEGO. Chris Phillips made some (reedswitch based, I think) sensors, and documented what he did. it requires some (...) (20 years ago, 16-Dec-04, to lugnet.trains, lugnet.robotics)
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| | Re: Grade Crossing Signal Thingy...
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(...) I know Lego doesn't make those sensors. The first post in that thread though is exactly what I was looking for! Thanks! I'm not too crazy about modding Lego so I'll go with the pure version. (...) Right, I'd think you'd need a lead time of (...) (20 years ago, 16-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) In fact for realistic operation (if you really want that!) you'd need 4 sensors, because the "exit" sensor is much closer to the crossing than the "entry" sensor in real life. But who wants realistic? This is LEGO! ROSCO (20 years ago, 16-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) Check the previous posts on (URL) the motorized cows. These use optical sensors to trigger cow head moooovement...I'm sure they could activate a level crossing using the same RCX optical detection scheme. -Rob A. (20 years ago, 17-Dec-04, to lugnet.trains, lugnet.robotics)
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| | Re: Grade Crossing Signal Thingy...
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I have a couple of newbie questions about things like this. First, how do you protect the motor? In this particular design it looks like you could actually rotate the arm past vertical, which I guess isn't a problem until you hit the ground on the (...) (20 years ago, 17-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) One approach is to use a linkage mechanism in which the gate is driven by a link that no matter how the motor rotates, never takes the gate below horizontal or beyond directly vertical. That of course introduces other issues, such as knowing (...) (20 years ago, 17-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) Easiest way is to have a stop of some kind at both extremeties of movement, and introduce some kind of slip into the drive mechanism, like rubber bands or a slip clutch (URL) each cycle runs the motor longer than it needs, and the clutch slips (...) (20 years ago, 17-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) The way that my design ended up, that isn't an issue. The arm just goes up and down as the wheel/motor rotates. It doesn't go past horizontal or vertical positions (by luck, not design :^) ) (...) There's a weak spot in my signals above the (...) (20 years ago, 18-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) Try braking. This is from memory so might be all wet... If you just turn power off, the motor coasts to a stop. But supposedly you can send the motor a speed 0 command, I think, and the motor stops right then, frozen in place. It takes more (...) (20 years ago, 18-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) How safe is it to routinely torque that slip clutch? I usually put it in for safety, but try not to need it -- something like a rope ladder for the upstairs bedroom. I'm thinking of a situation where a four-year old (and possibly several of (...) (20 years ago, 18-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) I don't know, I've never tested it under such duress. I don't imagine it would damage the motor at all, but it may damage the clutch after prolonged use. (...) I've found the easiest way is with rubber bands, and though it is usually a little (...) (20 years ago, 19-Dec-04, to lugnet.trains)
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| | Re: Grade Crossing Signal Thingy...
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(...) Yeah, I am not too crazy about modding LEGO either, but there are some mods that are fine by me. Chris's read switches are just such a mod. His crossing gates are awesome, and the read switches that control them work very well. I just I (...) (20 years ago, 28-Dec-04, to lugnet.trains)
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