dlp4341

Electify Your Train Switches

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I just checked out the latest issue of Railbricks (www.railbricks.com) this morning and on page 13 there is a reverse engineering challenge to build an all-Lego simple, compact switch motor that does not require modifying the switch. There are tantalizing photos of an already-built model.

Just thought I'd pass along the info to this group as I'm sure many will be interested (and may even want to take a crack at the reverse engineering challenge)!

--Rob

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Wow, it looks very compact! But I think that these solutions (I think that the motor is connected directly to the switch mechanism) have a problem, when the thain runs in the reverse direction it usually derails because the switch is "blocked".

Edited by aprendiendo

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I also noticed that and, given this thread, was disappointed the solution appeared on the reverse enginnering part.

Hope someone solves it quickly so we can see it's implementation... :classic:

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Here's an all-Lego solution, bar the PF-to-NXT converter cable.

points_motor.jpg

The design isn't mine - it's here on Flickr. As it's two years old, I'm surprised no-one else here has found it. I've left off the side panels for the moment as I've got precise movement driven from the NXT controller.

Jonathan

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Here's an all-Lego solution, bar the PF-to-NXT converter cable.

points_motor.jpg

The design isn't mine - it's here on Flickr. As it's two years old, I'm surprised no-one else here has found it. I've left off the side panels for the moment as I've got precise movement driven from the NXT controller.

Jonathan

It actually has been posted in another thread somewhere I think. I've been using it myself. :classic::thumbup:

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Hi all,

I guess it all comes down to whether you are satisfied with a non realistic looking switch box, just for the sake of it being "pure". Or whether you prefer an extremely realistic and elegant looking switch like Skaako's . I for one think Mike nailed it. You cannot get a cleaner looking solution to this "problem". The all lego version's are all big ,clunky and damn ugly and if i had to look at that all the time i would rather leave it as a manual switch.

Oggy

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I just checked out the latest issue of Railbricks (www.railbricks.com) this morning and on page 13 there is a reverse engineering challenge to build an all-Lego simple, compact switch motor that does not require modifying the switch. There are tantalizing photos of an already-built model.

It does look quite good, it will be interesting to see what comes up in the next issue. Although it would have been helpful if they said if the motor can be continuously run or not, i'm guessing it can be.. but just guessing.

Wow, it looks very compact! But I think that these solutions (I think that the motor is connected directly to the switch mechanism) have a problem, when the thain runs in the reverse direction it usually derails because the switch is "blocked".

With looking at this design i don't think it has that problem derailing, as it still uses the spring mechanism inside the switch to allow the train to pass when it is switched to the siding.

Hi all,

I guess it all comes down to whether you are satisfied with a non realistic looking switch box, just for the sake of it being "pure". Or whether you prefer an extremely realistic and elegant looking switch like Skaako's . I for one think Mike nailed it. You cannot get a cleaner looking solution to this "problem". The all lego version's are all big ,clunky and damn ugly and if i had to look at that all the time i would rather leave it as a manual switch.

Oggy

Thanks Oggy default_classic.gif Although i'm still in pursuit of finding a better motor that can be used without having to reduce the friction in the switch. Thanks again default_classic.gif

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Here's an all-Lego solution, bar the PF-to-NXT converter cable.

Hi Snapshot and Brickaroo,

I am using this design as well, however I had some issues with having it ripped apart after 20+ repeated turns, particularly when not using the panels (as in the original design) serving as stop and also removing forces pointing up considerably.

Did/do you experience the same?

Regards,

Thorsten

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Hi Snapshot and Brickaroo,

I am using this design as well, however I had some issues with having it ripped apart after 20+ repeated turns, particularly when not using the panels (as in the original design) serving as stop and also removing forces pointing up considerably.

Did/do you experience the same?

Regards,

Thorsten

I don't have that problem at the moment but I don't know how it'll stand up to a full day or two at a show. Because it's driven by a NTX brick I was able to experiment with different times and powers. I was able to set it to only rotate as much as necessary so the panels aren't needed as much. I am going to fit some (once they arrive) to see if they make any difference but I suspect they won't. If you're switching the motor manually then the panels will definitely be needed for long-term reliability.

Jonathan

Edited by Snapshot

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Because it's driven by a NTX brick I was able to experiment with different times and powers.

Hi Jonathan,

thanks for the fast response!

The NXT brick control taking care of the aforementioned problem makes perfect sense! I'll post some pictures of my approach in a couple of weeks (it's vacation time and I can't wait to get up to Northern Germany, where I was born ...)

I did some technic beam securing with rather limited footprint; you can bang the drive to both ends and it virtually cannot fall apart. But that should be done with care, since the motors may suffer from being stalled too long. I am also using multiplexed PBricks for motor control, so that makes things a lot easier.

Thanks again + best regards,

Thorsten

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Lego RR electric motor switch control

img0079ma.jpg

Hi All

I agree with all of you that the solenoid switch control was crude (see the beginning of this thread). I learned a lot with your help and now have a micro motor control solution. It only draws power when actually switching. It runs off 3 Volts , two AAs, that should last forever. It draws about 200 ma when the motor is running. The motor only turns a quarter turn, when power is applied , and is stopped in a stall mode. The torque developed is about 16 gram – cm. Since this torque is very low, the Lego train switches must be modified to remove the bumps on the switching arm.

The Lego box that houses the motor is a friction fit , and measures : 3 bricks high (H), by 4x5 (WxD) lego bumps footprint.

The control is a DPDT Toggle switch , the action is spring return to center, momentary on , center off, momentary on. The center poles are wired to the switch motor , with the outer poles criss crossed, and wired to the batteries . In operation the toggle is moved left or right and the motor responds by moving CW or CCW. The toggle’s spring returns the toggle to off when released.

The first three motors I tried, were removed from a dead DVD player. They measure about 1 inch dia x 0.5 inch deep, the shaft is 2 mm dia. Here is a source for new motors: cost $3. 50 USA. Switches cost about the same.

http://catalog.miniscience.com/catalog/motors/RF300CA.html

Remove the yellow switch arm. The bent wire below replaces it.The bent wire is coupled to the motor shaft with a short length of rubber tubing.

img0077ht.jpg

The bent wire is made from a three inch (76 mm) length of # 14 awg solid bare copper

A 90 deg bend at 1” from the end forms the shaft. Two loops are bent into the wire forming the manual over ride, and the actuation levers. The loops are formed by bending the wire around a 1/4 “ drill bit and a 1/8” bit. The height of the smaller loop (from the shaft to bottom of the loop) should match the yellow switch arm shaft to bottom dimension.

The coupling tubing is about 1/2” long with a 1/16” hole. As an alternate ; drill a 1/16 inch (1.6mm) hole through a pencil rubber eraser.

img0075ey.jpg

Edited by dlp4341

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very nice

is there a simple PF solution to remote track switching?

Not that I am aware of. That is why I have pursued a wired solution.

Any idea what are the worst case clearances ,both height and distance , for the track to structures next to the track?

The RC Switch engine LED and power switch are wide protrusions . Also the passenger train has a wide sweep.

Don

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My trains can pass without striking when track is laid side by side (on straights) so it should give you a decent clearance for your points.

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I agree with all of you that the solenoid switch control was crude (see the beginning of this thread). I learned a lot with your help and now have a micro motor control solution. It only draws power when actually switching. It runs off 3 Volts , two AAs, that should last forever. It draws about 200 ma when the motor is running. The motor only turns a quarter turn, when power is applied , and is stopped in a stall mode. The torque developed is about 16 gram – cm. Since this torque is very low, the Lego train switches must be modified to remove the bumps on the switching arm.

This is in my opinion one of the best solutions thus far...

My only issue is the required modification to the switches. Is there a motor option that generates enough torque to move the switch unmotified and still stall out before causing damage to the switch?

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This is in my opinion one of the best solutions thus far...

The fact you got the motor into the Lego housing with friction alone is impressive, I would love to hear from anyone else who has managed to make a brick built housing for an off the shelf motor (and who is willing to share of course)!

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Thank you all for your input

All my switches are modified for low torque.

Maybe some one could measure the force to change a standard switch with a fish scale to see how much force we are talking about.

Don

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I picked up a new pr of switches and measured the force to operate them .

I measured about 800 grams horizontal force to operate them. It feels like they require less force as they break in.

These will need a much larger motor, if used unmodified.

Don

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Hi there.

That´s are my Solution with a Micromotor inside.

Oversized Image

Edited by TheBrickster
Oversize image removed

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2 years back I modified a broken switch.

It works very well with just a simple toggle switch and a power supply. A spring makes sure the switch returns to the normal position.

It's very small and not that expensive, though there is some work to modify it. I'm thinking about painting it the same color as the track.

post-27539-133372829723.jpg

post-27539-133372830409.jpg

post-27539-133372841265.jpg

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Very clever modification, Jeroen!

Can you edit your post to say where you get the solenoids you are using, and if they can handle momentary power or longer duration power?

I am very interested in your solution, and am eager to modify mine this way!

Thanks!

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I got mine at conrad. The smallest ones I could find. There should be some available in the states.

http://www.conrad.com/CYLINDER-MAGNET-ITS-LZ-1335.htm?websale7=conrad-intπ=502601&ci=SHOP_AREA_83990_0214811

Just use any type of small cilinder selonoid.

If you put power on them for longer periods they will get hot, so best to switch it off again after the train has passed.

I'm thinking about making a timercircuit for it.

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many good solutions :thumbup: ,have personally struggled with this problem. Have got many ideas now on how I resolve this problem, thanks :shrug_oh_well:

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