Keyed docking ports

[StormKat]

I have built a ton of stations and I am pretty good at docking. I have used single docking ports and multiple docking ports. The docking port alignment mod is fantastic for getting those critical angles just right. But...

Has anyone done anything like a keyed docking port? A modified docking port that will only dock at one angle? Or maybe something with a Docking port with a Jr. Docking port just above it?

I can't seem to get the vertical alignment right because of the different thicknesses of the ports. The Jr. sits higher.

Can anyone shed some light on this for me?

Edited November 28, 2014 by StormKat

[robopilot99]

Not to be rude but what is the point? Two clamp-o-trons are quite rigid.

[sal_vager]

I think StormKat means a port that docks in an aligned way, so the two vessels are not rotated relative to each other.

[tomf]

Asyou say because of the different heights of the two ports what you want is going to be virtually impossible. The best solution for now will be to use two ports of the same size. In the next update you might be able to tweak the attachment or one of the ports so they end up the same height.

[StormKat]

Not to be rude but what is the point? Two clamp-o-trons are quite rigid.

I want to make a fool proof connection that guarantees the attached part is connected a certain way. Two clamp-o-trons would allow me to connect the module two ways. 0 degrees and 180 degrees.

[RainDreamer]

Hmm... Maybe in a different configuration, like making an L shape structural element with 2 ports on each leg?

[Kerbart]

Given that parts in a ship are organized in a tree structure with multiple nodes connecting to one parent and one parent only, how is docking with two ports possible in the first place?

[StormKat]

This looks promising. Finally a use for the micronode.

[HoY]

If you use the 4 port adapter, and use 2 regular clampotrons on opposite corners, and 2 shielded clampotrons on the other 2 corners, that will give you a keyed docking adapter that works in 2 ways, but not 4. The shielded ports will dock with the unshielded ports. It doesn't solve the problem 100%, but having a light or battery on the same side on both adapters can ensure you line them up to the same size

[StormKat]

Hmm... Maybe in a different configuration, like making an L shape structural element with 2 ports on each leg?

Only one actually is docked. The other connects on magnetic attraction alone. I use the technique often on my stations.

For example --

[StormKat]

If you use the 4 port adapter, and use 2 regular clampotrons on opposite corners, and 2 shielded clampotrons on the other 2 corners, that will give you a keyed docking adapter that works in 2 ways, but not 4. The shielded ports will dock with the unshielded ports. It doesn't solve the problem 100%, but having a light or battery on the same side on both adapters can ensure you line them up to the same size

That's the same as the two clamp-o-trons. They work two ways.

My Hex Station is what started all this. I got two of my arms backwards. The in-line clamp-o-trons point inward instead of outward.

[Starman4308]

One thing which could be done is to have each stack have both a Clamp-o-Tron and a Clamp-o-Tron Jr. That way, the total height of both stacks is identical. You'd just have to be a bit careful about uncoupling to make sure you don't ever release at the wrong point. It'd look a bit like this (the one on the right has the Clamp-o-Tron Jr. completely hidden below the full-size one).

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[Rhomphaia]

One thing which could be done is to have each stack have both a Clamp-o-Tron and a Clamp-o-Tron Jr. That way, the total height of both stacks is identical. You'd just have to be a bit careful about uncoupling to make sure you don't ever release at the wrong point. It'd look a bit like this (the one on the right has the Clamp-o-Tron Jr. completely hidden below the full-size one).

http://imgur.com/a/CcgXq

Could just use a battery underneath a clamp-o-tron

[Master Tao]

How about a physical key?

The girder extends slightly past the docking ports, so if you have two of them on the same side, they collide before the connection is made. Rotate it the other way and you can easily make a connection. You might even be able to make guide fins if you're very careful.

[HoY]

Well, the same concept works for 1 unshielded and 1 shielded port on a 2-way splitter too. Cuts down on extra part count also since you won't need spacers.

[tg626]

Get navyfish docking alignment mod and you can see if you are aligned at 0 degrees or 180 or whatever.

[StormKat]

So many good ideas!

I did confirm that the micronode works.

[StormKat]

Get navyfish docking alignment mod and you can see if you are aligned at 0 degrees or 180 or whatever.

I've got it and use it all the time. I was just wondering if there wasn't a stock solution.

Hoy, I may try that as well.

Thanks everyone!

[SciMan]

If you're looking for degree-perfect docking, that "keyed" one using a modular girder looks to be the best stock solution I've seen so far.

It won't wobble any more than a bicoupler with two standard docking ports will, because there isn't anything else in the stack between the ports and the bicoupler.

At the same time, the girder means that it will only connect to an identical setup in one orientation. And as shown by the picture, that girder makes a good place to put a light for night-side docking, tho I would have used the floodlight instead. Spotlights are overkill up close because they wash out important details unless you turn them down so far that they're not useful at their normal useful range anymore.

Speaking of wobbly docking ports, that's a potential downside I can see to the solutions using 1.25m stack batteries or a combination of jr. and standard docking ports.

The different types of docking port are probably differently flexible. If that's the case, putting force thru that connection will bend the stack toward whichever side has more give in it. Additionally, IMO using the 1.25m stack battery is an open invitation for wobbly rockets.

If you're just looking for a "which way is up" indicator for your docking ports, use a Z-100 battery pack (the small rectangular one) The green dot on top of that thing can be seen in the dark, and I haven't seen a cheaper docking port alignment indicator yet (1 part, only 80 funds, doesn't unbalance the craft because it's physics are disabled, and doesn't go in-line to make the connection even more wobbly than docking port connections already are.

If you're open to using mods, MechJeb's SmartSAS can align docking ports to sub-degree accuracy. I use that all the time for docking.

(I know there's a typo, I'm using it to avoid a "scunthorpe problem" in the word filter)

To make it do that, select "control from here" on the port you want to use on your ship, then target the port on the target craft that you're docking to.

Now bring up SmartSAS, and click "TGT", then "PAR -". When your ship stops rotating, the "controlled" docking port on your ship should be facing the targeted docking port on the other craft.

Finally, turn on the "Force Roll" option at the bottom of the SmartSAS window. If it stops rotating at the wrong angle, change the number in the text box at the bottom of the SmartSAS window. It will take any number positive or negative, but it will avoid doing more than one half rotation. However, you can force it to go in circles if you go in 90° increments and let it settle each time.

That "Force Roll" option is the part that's doing what OP wants. At least, it seems like that's what they're looking for.

If you don't want MechJeb but are OK with mods, there's always Infernal Robotics.

I know that thin rotational servo parts sized to stack under Jr, Standard, and Sr. ports existed for Infernal Robotics at one point.

While I'm not sure if they got merged with the main download or are still their own download, I'm fairly certain that they're still maintained.

After all, this is a common enough problem, and IIRC the docking port servo parts were fairly popular.

Edited November 28, 2014 by SciMan
updated

[cantab]

I'd point out that all the multi-port solutions so far are vulnerable to having only one port connected, and thus some misalignment. The only real idiot-proof way I can see is to have a "key" structure that goes the full way round the port(s) to allow just one orientation.

[Kesa]

I'd point out that all the multi-port solutions so far are vulnerable to having only one port connected, and thus some misalignment. The only real idiot-proof way I can see is to have a "key" structure that goes the full way round the port(s) to allow just one orientation.

No. If ports are really aligned, both ports are connected. You can try by building it in VAB : the physically attached port will say "decouple node" on rmb, the other one will dock just after launch and say "undock" (I don't how it works with tree structure though)