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Can a lightsensor be used with set 8479?


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#1 simonwillems

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Posted 26 April 2007 - 08:48 PM

I am planning to make a railwaycrossing with automatic barriers using to little red 9v motors, it'll be nice for the barriers (and the traffic depending on the closure) to "know" when a train is coming.

I own set 8479 with the little computer in the back that reacts when you push the touchsensors, but will it react when a lightsensor is attached to it instead?
Does anybody know? It'll be pointless to bricklink a lightsensor and then find out that it doesn't work...

I hope to hear from you technic experts!

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#2 Landlubber

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Posted 04 May 2007 - 10:46 AM

I don't have any of these sets so I'm hardly an expert, but couldn't you use the touch sensor placed further up the track in a way that the train sets it off as it goes past thereby lowering the boomgates. You then have the second sensor (that set comes with 2 doesn't it?) on the track over the other side of the barriers so that when the train passes it the barriers raise again.

As before , I've never used the little computer thing so I dont know what it can be programmed to do, but if it could do that it would be pretty bloody cool.

#3 simonwillems

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Posted 04 May 2007 - 12:41 PM

Thanks for reacting on my topic!

Using those touch sensors may also be a good idea (and cheap too, because I already have the two sensors!) I already tried to figure out how such a sensor could be placed underneath the track somewhere but haven't yet found a perfect solution.
I'll just keep trying. The idea of using both sensors never occured to me (I had something in mind with timers to make the barriers go up and down) but this sounds more sensible. Thanks.

:-)

#4 Holodoc

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Posted 04 May 2007 - 12:55 PM

Where do you have that lightsensor from?
If you are using the Mindstorms RIS 2.0 you can download Brickjournal #5 here. Look at pages 106ff. There is a complete design for a remote controlled railway crossing. :-)

But I assume you only have the 8479 and got the lightsensor elsewhere. 8-|
The electric code pilot should be able to react on both sensors, touch- and light- as they have the same 9V "ending". Light should be "on", and dark should be "off" (or vice versa :-) ) for the lightsensor, but I havenīt tried that, because I, like Landlubber, do not have the Barcode Multi Set. But you canīt damage your set by just trying if it works.

EDIT: I just read you posting again.  :-$ So you donīt have a lightsensor yet! X-O
Then I would be careful and go on asking if somebody already tried to combine both pieces. X-D

Help on!
Even more interested in LEGO bricks & parts? Read Tim Johnson's (aka Caperberry) blog: Posted Image

#5 simonwillems

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Posted 04 May 2007 - 02:02 PM

View PostHolodoc, on May 4 2007, 12:55 PM, said:

If you are using the Mindstorms RIS 2.0 you can download Brickjournal #5 here. Look at pages 106ff. There is a complete design for a remote controlled railway crossing. :-)

Thanks for the link, although I don't have a mindstorms RCX it can be helpful. The barcode computer works less complicated (and has less functions) but I think it can be done.

The only problem is speed: when the train rushes by it will pas the crossing in less than 3 seconds, my track isn't that extensive that the barriers will have the time to fully raise and go down again before the same train has completed the circular track and is back at the crossing.
So the train must run at it's slowest speed, or the barriers need to be raised and lowered at lightningspeed....

8-|

#6 Mr Hobbles

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Posted 04 May 2007 - 10:33 PM

I'm not sure if it will to be honest; I seem to remember the light-sensor from the RIS 1.5 reporting a value between 0 and 255 instead of 1 or 0.

#7 Landlubber

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Posted 05 May 2007 - 11:02 AM

View Postsimonwillems, on May 4 2007, 11:41 PM, said:

Thanks for reacting on my topic!

Using those touch sensors may also be a good idea (and cheap too, because I already have the two sensors!) I already tried to figure out how such a sensor could be placed underneath the track somewhere but haven't yet found a perfect solution.
:-)

What about next to the track somewhere? You could then have something sticking out the side of the train ( small flexible pipe or something spring loaded ) that will just brush the sensor as it goes by.

As you say, the speed of the train will be your main problem.



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