Controlling a crossover

[Duq]

A few weeks ago I came across a solution for controlling Lego's double crossover created by @scruffulous. It uses a key to move the two sides into various positions.

Automated double crossover points by Mike Pianta, on Flickr

As he noted himself, changing from one end of the key to the other takes a little time. That made me wonder if the key could not be rolled up into a rotary solution. And so I came up with a solution that uses the Technic cam parts:

Crossover Control by Duq, on Flickr

It works, but it was just too tall for my liking. I eventually wanted to control both ends of the crossover together and for that I needed the axle to run below the track. Back to the drawing board then. Turns out you can do the same with simple 1x2 half beams/ lift arms:

Crossover Control V2 by Duq, on Flickr

The final step then was to build the full size solution and add an RCX to control it all. So here's my completed prototype/ Proof of Concept (click to open in Flickr and see the video):

Crossover prototype by Duq, on Flickr

As you can see you don't control each of the four switches independently, instead you control each of the two crossovers, flexible enough for my liking. You could of course double up and have an RCX at each end if you do want to control all four switches.

[High_Admiral]

Interesting. How well does this work?

[zephyr1934]

Brilliant work!

[Toastie]

Hi Duq,

very nice work. I really like the RCX solution a lot. And of course the "non-invasive" mechanics!!!

I made a version, which needs some invasive work: remove the both lids on the back, remove the lever. Drill a total of 8 small holes. Then use four 1 mm dia Nylon wires running in LEGO flex tube. All wires a thrown simultaneously by one PF-M motor into either all-cross or all-straight position within the faction of a second. Must have been don elsewhere so I did not post. Just in case here are two pics.

Really nice work. I love this mechanism.

All the best,
Thorsten   

 

[ElectroDiva]

This is fantastic @Duq - very clever mechanism. Just wish there was somewhere to get 9v double crossovers

[Duq]

@High_Admiral I haven't used it long-term in a layout but the kitch-table tests sofar have worked well.

@zephyr1934 Thanks!

@Toastie It's not entirely non-invasive... You'll still need to open up the bottom and take the slider out. I haven't done that yet with mine. For the video I've put the sliders in the middle, so the points don't fully open. It works to show the principle but I'd expect a lot of derailments using this for real... I haven't seen your pictures yet. The old Brickshelf problem of 'this folder is not public yet'...

@ElectroDiva Don't we all! There is a guy on Bricklink who makes custom ones but they're not cheap... https://moc.bricklink.com/pages/moc/mocitem.page?idmocitem=1389

[Toastie]

3 hours ago, Duq said:

'this folder is not public yet'

Oh my … so here is one - and here is the other. Bad quality though.

Best
Thorsten

 

[ElectroDiva]

Thanks for the link @Duq - his work looks great - have messaged him.