Portal Gun Stand/Pedestal. Am I the first?

[Rurouni Kalain]

Greetings!

So I got the NECA Portal Gun prop a few years back and while it's EVERY bit as awesome as you think it is, I sadly have no place that is fit to hold it's awesomeness. So I'm constructing a "Portal Box" as it were. It's going to have a Rasberry Pi in it to control sound and music, an old PC in the case to run Portal on it with a monitor, and an Arduino with a stepper motor to turn the gun, pull the trigger, etc...going to be awesome.

I've been busy with many projects and school for a while, but I'm finally back working on this. The current issue? Well, watch this video I made to see. (2m 06s for the main issue)

Like it? Thanks. Oh by the way, shameless plug, watch my other videos and subscribe if you like what you see.


ANYWAY

That's the issue. How on earth do I enable the turning of the blue semi-circles inside that tiny space that is available? I'm willing to make things a BIG larger than they have to be in order to make it work, but my father and I are really at a loss as to how to do this and we may just have to settle for something more...feasible.

However, here's hoping that we don't have to do that! Come tell me your ideas people, I'd love to have this become a true accurate reality and share this project with the world. ^.^

Right now I'm thinking that some mini drum rollers would be the best bet.

So to sum up..the issue is HOW do we get the blue semi-circle it into the black semi-circle/pipe? Motors? Pneumatics? Pulleys? Conveyor Belts? Drum Rollers? How do we make it fit.

Thank you for looking!

 

[Gixxerfool]

I see a few issues with trying to make that happen. Internal friction will be a large hurdle in the space provided. And as you said, trying to make it happen. A drum roller like a capstan would be where I would start.

 

[Darth Lars]

The arcs of light in the video are perfect half-circles and the brackets are perfect half-circle ... To make a moving mechanism that does not fall out, you would either have to make the light telescopic or you would have to change the ratio of light vs bracket.

Instead of something that moves, you could use a string of LEDs that go off in sequence to simulate the effect of movement. You could look at using neopixels for that.
Then remove the light fixtures when you want to get to the gun.

Edit:
Or maybe the best would be a combination of neopixels and movement. Make the arcs longer than the brackets. The arcs would then of course not be able to fully retract into the bracket. Use a sensor to detect when an arc is retracted as much as it can, and let that trigger a routine on the controller that would turn off the remaining LEDs in sequence at the same speed as the arc's movement.
That would require quite a bit of fine-tuning to make the LEDs turn off in sync.

 

[Rurouni Kalain]

Gixxerfool, could you tell me more what you mean there about a "capstan"? Don't know much about what that is.

Darth Lars, unlike what it looks like, those light-blue half circles, do NOT light up, nor do I have any intention what-so-ever of lighting them up. If you take the prop into a dark area, they don't glow, so I don't plan on doing that. It's simply going to be an acrylic that I bend into the correct shape. As for those LED strips, I do have some plans for those in something else in this project---the box that this thing will be held in, but that's something I've mostly worked out.

I thank you both. Please keep this discussion up and going by all means!

 

[logan74k]

Mmmkay! I'm here because I've got a soft spot for complex silly engineering. Decided to build a walking humanoid robot in grade school. (this was very early 90's mind you) Did I do it? Of course not. That's beside the point. I still get in way over my head on a regular basis though.

Let's keep defining the issues here:

-There's little to no room for a mechanism outside the tube for the first and last third of the trip, and both ends of the rod need to remain clear/blue

-Unless the tube/rod fit is perfect and everything is dead level and true, the rod will presumably need some kind of guidance to reliably and solidly hit its target when returning to the locked position.

-As gixxerfool mentioned, if the fit were very precise with just a little bit of play, the internal friction would necessitate lubrication, which would rule out the use of a rubber wheel to drive the clear rod reliably.

-Given the other constraints, the black tube must almost certainly be more than a half circle, if only by 3/4" or so.


Here's what I'm envisioning - you have a 2 stage system to get the rod to make one full half revolution. The rod must fit the tube very closely in this concept.
In the bottom center, above the arc of the circle where you have more room, you have a roller with teeth. This is the second stage during unlock and first stage during lock.
The end of the rod which is always buried has some material removed to allow for a metal catch or 'key'. This is the first stage on unlock and second on lock.



How it 'works': On unlocking: The key on the lead is attached to a push/pull mechanism buried opposite the toothed roller in the middle bottom of the black tube section. In my sketch it's shown as a roller, though this seems more of a one-way solution and tricky for re-locking. I partly sketched it ouside the tube for clarity, but it would all be inside. The lead pulls the rod down into the tube all the way to the halfway point where the key drops out.
As the tube reaches the halfway point the toothed roller takes over, obviously spinning at a speed to precisely match the previous motor's pull rate. This second stage guides the rod all the way to it's final 'unlocked' position.

On locking: The toothed roller pulls the rod back out to the halfway point where it runs out of rod. The key re-engages from below (perhaps by spring mechanism, this part isn't fleshed out) and the magical roller device now pushes the keyed rod back to its original locked position.

The issues I see with this are:

the toothed roller will more than likely mangle the rod in short order, albeit in a single straight line
the key needs a fleshed out mechanism for traveling up and back the first half of the tube
the issue of landing the rod in the exact spot on re-locking isn't sorted.

I'm guessing this is more elaborate than you'd like, but hey, it's a tough problem. Something to think on at least.

 

[zapwizard]

Here is my diagram about how you could do it pneumatically. You would need a larger diameter outer tube, with stops at the end. You would attach a rubber washer to the end of the bent acrylic rod. After that it works just like a pneumatic piston. You wouldn't get a 100% open/close effect however, but you could have it open far enough to remove the gun.

 

[Rurouni Kalain]

Silly engineering? Yeah, suppose that does work pretty well for this doesn't it? xD

@logan74k First off. Wow. Thanks for making that drawing, that means a lot that you would even do that!

I hadn't given as much thought to lubrication as for the most part I was thinking it was just going to be a perfect fit. I realize it is important to keep in mind, though I don't want things to get messy in there. Don't know much about lube type things for stuff like that, how often it would need to be replaced, cleaned, etc. Hoping not to have to worry about it, but if so, then so be it.

The "roller with teeth" is stationary in the middle correct? Because if so, I was thinking of bit of the opposite; the bottom center being the 1st stage on unlocking and 2nd on locking. I don't see quite what you mean in terms of how it would even grab it and get it to the point where the key COULD even be 'sprung' back into it. What am I missing?

@zapwizard To you, the same. Thanks for making that picture/diagram!

Something to keep in mind, I had not thought of a stopper like that before, though I am hoping to go for the full rotation of course. What is the amount of pressure I would need for that work? I don't know much about that sort of thing.

 

[Ghost Host]

Great idea.

 

[zapwizard]

Something to keep in mind, I had not thought of a stopper like that before, though I am hoping to go for the full rotation of course. What is the amount of pressure I would need for that work? I don't know much about that sort of thing.

The pressure would have to be something you work out when you try building it. I recommend making a proof of concept prototype. Use straight PVC to figure out your stopper, and gaskets and then curve it an try that. There are lots of guides on making PVC Pneumatic Cylinders online. (note I haven't built any, but I have seen them used)

 

[logan74k]

The "roller with teeth" is stationary in the middle correct? Because if so, I was thinking of bit of the opposite; the bottom center being the 1nd stage on unlocking and 2st on locking. I don't see quite what you mean in terms of how it would even grab it and get it to the point where the key COULD even be 'sprung' back into it. What am I missing?

When it's locked, there is almost no clear rod inside the tube to grab. That was my hangup there. The bottom center teeth wheel can't be the first stage on unlocking because it's operating against a hollow tube. You got to get the rod halfway down in there before the teeth can grab it.

Once it gets to the halfway point on unlocking and the teeth grab the rod, they will be constantly in contact with it until you got back to halfway 'locked' again. So, the teeth drive it back to halfway on locking where the key 'springs' back into place and pushes it the rest of the way closed. Hope this makes sense.

Any progress on deciding what you're going to try? I like the pneumatic idea as well, you could probably figure out some kind of valve mechanisms to make that work as intended too.

 

[Rurouni Kalain]

Thanks to both of you.

Right now, school is eating up much of my time right now so my time towards this is limited--but, that's a temporary thing as these are my final classes.

Until this thread, my 'best' ideas was thinking of a pneumatic/drum roller combo, so this is great thinking about ideas I hadn't thought of before, ha ha.


Okay, so it took a bit, but I think I get what you are saying more so now logan74k . One, was understanding that when you say "unlocking" you mean bringing the 'clear rod' INTO the tube. Gotcha. The other was getting that when the rod is in the 'locked' position as you put it, that the 'key' is already IN that little notch/bit removed. NOW it's making more sense.

When you want to unlock it, you ~pull~ it down to the middle, where in the key falls out, and the roller takes over.

So, why teeth, why not a smoother drum roller that wouldn't cause damage?

That said, I get what you mean now in terms of the issues. How do you then get it to finish 'pushing' it back up into the locked position. I like your idea, complex, but yeah, it's...different.
zapwizard if there is a way to do it just like how I want, that might be better. Until you brought it up, I just hadn't thought about using ONLY pneumatics for it.