Air-Powered Star Trek Style Door

I always wanted a piece of Star Trek and the Disney Monorail in my house, and one thing they have in common is that they both have automatic sliding doors. It would be the perfect, most geek-ified entryway for my bedroom.

Edit:  Not every detail is included in this Instructable.  I did the best I could using pictures I had taken 4 years ago.  There are some more details on my blog if you would like to read more:  http://uiproductions.blogspot.com

To be acceptable as a permanent renovation to our house, I knew the door had to have a normal appearance, as well as be practical and maintenance free. To reduce the number of moving parts (and maybe for a little coolness factor) I decided to make the door air-powered. The air would be supplied by a small compressor and storage tank located in the attic. In order to open and close from the inside and out, the door needed a little bit of brainpower. I decided to use a small PIC microcontroller, my platform of choice still to this day. Arduino didn't exist back then.


With a rough plan in my head, I drew a quick CAD model of the door and the brackets that would connect the pistons to the door halves. I was ready to start purchasing parts.

Step 1: Buy Parts / Tear Out Wall

Here are some of the parts I used: 

- Craftsman 1 Gallon Air Compressor / Tank
- 32" wide, solid wood door from Home Depot (to be cut in half)
- Pocket Door Track from McMaster.com
- Two 16" stroke, 3/4" bore pneumatic pistons from McMaster.com
- A 5-way, 12V solenoid-operated valve from McMaster.com
- Various pneumatic hose, fittings, a regulator, push-on hose connectors, two valves for air supply and purge

Your parts will vary depending on your door size, your wall configuration, etc. 

Start tearing out your wall with a hammer, crowbar, or any other destructive tools you can find laying around.  This is the fun part of the project!

Step 2: Install the Track, Hang the Doors, and Patch Up One Wall.

I proceeded to cut the solid wood door in half with a circular saw, sanding the edges when done. I considered using bi-fold doors which are already the right size, but they didn't give the appearance of a normal door when joined together.


With all of the interfering studs removed from the wall, I held the rear drywall in place with 3/4" thick wood boards, which would still leave room for the door to travel through the wall. I added a new 2x4 stud on one side to support the pocket door track, and installed the track and a door half using the included hardware. You can see below how the one half will slide into the wall cavity.

Some strips of drywall, mud, and trim take care of the hallway with no problem.

Step 3: Fabricate Door Bracket / Install Pistons

Next I had to fabricate a bracket to connect the pistons above the door to the actual door.  I welded up a bracket out of some steel flat bar from Home Depot and attached it to the back of the door with a spacer block. I could have really used some more advanced tools at this point, but I had to work with what I had at the time.  You can fabricate this bracket from sheet metal, steel bar, wood, or whatever you can find.

With the two brackets fabricated and installed, I mounted the two 16" pistons above the door, side by side. Air supplied to the back of the pistons would open the doors, and air supplied to the front of the pistons would close the doors, as seen below. I rigged up the valve temporarily to test everything out.

Step 4: Electronics

For the electronics, a simple on/off switch would have worked.  But I wanted to get a little fancier and control the timing of the doors opening and closing.  I made the circuitry from components that are readily available at Radio Shack and Sparkfun.com.   The circuitry just waits for the button to be pushed then switches the air valve on so the door will open.  After a few seconds, the valve switches back off and the door closes.

I mounted a DIP socket, a relay, and a few other components on a Radio Shack perf board, and placed the whole thing inside a plastic junction box.  I also wired in two AC power switches, one supplying AC power to the wall adapter for the circuitry, and the other supplying power to the compressor in the attic. I wanted the whole system to be enabled and disabled from this "control panel", including the air supply.

Step 5: Test It Out / Patch Up the Wall

After countless cycles of testing and tweaking the door operation with the wall open for a month or two, I finally felt comfortable closing up the wall. Here you can see some of the new drywall starting to go back up.

From there it was just a matter of painting the wall, and it was back to looking stock. I purchased a blank white wall plate from Home Depot. I drilled it out for an illuminated pushbutton and a 3-position keyswitch, both of which I bought from McMaster. I also purchased a plastic hatch door from McMaster for the control box. Lastly, I added an air conditioning vent above the door. This lets the air venting noises be heard, and it also provides me access to the valve and pistons should anything go wrong.

After you've tested the door and patched up the wall, that's about it!  Good luck with your project and feel free to post comments and ask questions if I skipped over anything you might need help with.  Thanks for reading!

Comments

[-=Dr.Who=-]

This is very cool. An automatic door is always nice. There is a question of safety that comes to mind as yoguy121 brought up. What if the door were to get stuck? What if you lost power or worse, there was a fire. If you don't mind some suggestions, this may save your life or your child's.
The "return action" of the Star Trek Turbo-Lift doors didn't really have a sound to them (until much later in the series that is). So, perhaps the "return spring" method of closing isn't such a bad idea.
The thing I find dangerous is that you didn't incorporate any kind of "Manual Override" in your design. Since you're using compressed air as the actual power for the door pneumatics you wouldn't need electrical power in an emergency. Just a bypass valve in one of your access panels or add a new panel or two. One for both sides of the door, because you never know what side you're going to be on when power goes out and you need to get in (or out) of the room.
Also, if you're thinking that a battery backup will suffice to answer these issues, you're just begging for problems. Battery powered UPSs are notorious for having the battery go bad from non-use. Yes I said NON-use. Plus the power that compressor takes at start-up will just pop the weak little breaker on the UPS leaving you still stuck on one side or the other. So I wouldn't bet my life or my kids life on a $50 UPS you got at Best Buy.
This is a mechanical device and it should have a manual bypass. Seems to me that this is a no-brainer and all that's needed is a couple 1/4turn ball valves and a couple anti-reversing valves installed.
A "Neat Door" is not worth dying over because you cheaped out. In my opinion, there is never a "Good day to die".
This is very cool though. There are still other things that you could do to it. Like add an RFID system or Thumb-print scanner or freak out your friends with an Ocular or Handprint Scanner to open the door! How about Voice operated command system or just a simple contact pad (like in the grocery stores) or a short range motion detector to activate it.
Also, there is a "single ram" method to open both doors that goes hand-in-hand with the "spring return" closure, using a thin cable and a couple small pulley-type wheels. Super simple design uses only 1 air line to the ram! This would decrease the cost and complexity of the build by a factor of 4 (don't ask, it just sounds good). So, you could have done either 2 doors with the parts you now have or just saved youself from buying the second ram, the extra hosing and fittings and the time it took to install all that extra stuff.
If you're interested, PM me and I'll send you a drawing of the modification.
These are just some things to think about.
Good job with the instructable. I liked it and so did a bunch of other people!

[uiproductions]

I really appreciate all the comments everyone posts, but you wrote an awful lot for not reading much. There is a manual valve right by the door to release the pressure. Check out my site for more details. There are a few things that I left out of the instructable to keep it simple. I can't tell you exactly how to build your own door, but I can at least show what I did.

Having two cylinders was the simplest option for me at the time, not having any fancy tools to fabricate a pulley system. I don't understand how adding two pulleys, a cable, and brackets would simplify things more. They are both equally good options in my opinion.

A battery backup is just a convenience. If the power goes out, the door will still function normally. It doesn't replace the manual override or the fact that you can just force the doors open by hand if you need to get in or out, which I have done before. I wouldn't be buying a UPS from best buy, I would design a PCB for battery management. That's what I do for a living now.

Nobody is dying because I "cheaped out". If the power goes out, there is a manual override. If the compressor doesn't run, the lines will eventually lose air pressure and the doors will be even easier to open by hand. And heaven forbid, if the door doesnt open and the room is on fire, just climb out the window that's two feet away, don't be stupid.

But seriously, there are always going to be more "nice to have" features. I built it to be practical and unnoticeable, which it is for the most part. I don't even live in the same city anymore, and the door still works great 4 years after I built it. It saves space, it is easy for ANYONE to operate, and it looks cool! There are plenty of other uses for it to, such as in homes of people with disabilities.

Thanks for the constructive criticism.

[JeffT125]

So how are they working after another 6 years? I really love these and want to do my own. Nay additions? Can I get the parts and wiring for the control panel?
I would love to make an Amazon Echo app for it. Open the door by voice with a voice pin numbers for unlock.

[-=Dr.Who=-]

I went over your instructions a few times and nowhere in it did I see a mention of a manual release nor could one be seen by any obvious means. I must not have been the only one who missed it as I saw a couple of comments about these things.
The reason I wrote so much was to make my point clearly understood. I'm glad to see it was, thanks for answering.
I just think it's kind of strange that you didn't mention these things as they would undoubtedly come in to question the first time someone else tried this and stuck in or out of the room. And I'm always looking at the safety of things in our everyday lives to see if I can improve on the original design. I'm a hobbyist inventor and I have a some experience with these types of doors. You see, I used to work on elevators. And the worst part about losing power to an elevator is that there is no manual release for the outer doors. They can be opened but I had to create the tool to do it. What a pain! But, it was part of my job and that's part what I do for a living.
So, not finding any info on releasing the door manually and your response to one commenter with the Worf quote, made me think that you totally overlooked these things. I know how these things work. You build first, then test, THEN put in safety devices. I do it all the time. it just would have been nice to have had that included in your instructions. That's all I was saying.
But you did this and took all the pictures over 4 years ago? When did you post this?

[yankees3142]

Elevators have been around for how long? and a device/procedure had never been created in the past to open an elevator door from the outside?

[-=Dr.Who=-]

That's right. There's no easy way to open the outer doors when something like a power failure happens. You can lower the car to ground level but the doors are still locked closed and there is no panel you can open to release the outer doors. That's why it takes so long to get people out an elevator. Not too sure about elevators that use cables, but the hydraulic ones I've worked on were all like that.
Have you ever worked on Ben Dover Elevators or ever worked on any type of elevator for that matter?

[hintss]

why? also, isn't there another door on top of the elevator?

wait, the outside doors are usually opened by a motor on the elevator car, right?

[DavAnt]

Sorry to reply on such an old post, but actually, I know of elevators that have a system to open them from the outside when there is a power failure! There is a small hole in the door, usually near the top, where a key/tool can be inserted to crank the doors open by security personnel or staff.

[uiproductions]

Check out the control panel at the top right of the door. In my demonstration video at the start of the instructable, I mention that you can shut off the air supply to the door from that panel.

Yeah, sorry, I thought I had linked to my blog from here. The instructable was done in a little bit of a rush and probably deserves some updating. Full details are at my site.

I built the door 4 years ago and never posted anything about it. Every time I go home for the holidays I see the door and realize how cool it is. This Thanksgiving I decided to take a video, and I dug up the pictures I took during the build from my old computer.

[-=Dr.Who=-]

Hey, I'm not knocking ya, this is some slick work, for sure. I know it was a lot of work to tweak everything and get it all working the way you wanted it before you sealed up the walls and painted everything. It looks picture perfect too.
I didn't watch the video (at first) because I just wanted to read through everything first to get an idea of what your total project was about. Besides, people forget to include important details in most videos. They just aren't worth wasting time on unless it's clearly stated that there is information in the video that details something not easily explained in writing, like knot tying. Try explaining in writing how to tie a Turkshead or Monkeyfist to someone without showing them. Then, I would expect to see more mention of the video and that it needs be watched in order to understand. Even though it was mentioned, it just sounded optional.
But isn't the purpose of this site to put up ALL the information on how something is made and how you did it so someone else can do it too? Or, is it just a means to drive traffic to your site? (Now that I'm thinking about it, that's really a good idea, but it doesn't seem fair to use the site like that). But, when in Rome, right? LoL!
Either way, I totally dig the end result. I just wanted to point out the one thing I thought was overlooked, so others would stop and think a bit and maybe come up with their own way of implementing some safety measures.
Even more impressive than the door, is the fact that you built it 4 years ago and were able to pull together such a great instructable! I know my example of the house on fire is a bit much but I used to work in the Nor-Cal 911 call center.
I'm glad that you were thinking and did have a manual release in it somewhere at least I lust wish you would have shown how you did it. What can ya do now, right? ;)
One last thing... In the original Star Trek series, the doors weren't air-powered, they were powered by FDAs or Flunky-Drive Actuators. (Flunky-Drive Actuator = a stage hand)LoL!

"Damn it Jim, I'm a doctor not a brick layer!"

[tday99hotmail]

Dr. Who? you have too much time, stop wasting time and get back to work!
Uiproductions, great ible. You've inspired me to make an air powered door in my basement! I might even include a safety release on both sides(an ax because valving etc is too complicated).
HAHA!

[paganwonder]

Great 'ible! Really like the "Disability" angle. Having broken more than one door by "accident" I would say- "When the flames are lickin' your a$$", even a small child can bust thru most non-secure doors.

[-=Dr.Who=-]

Ya, we hear so many stories on the news about children in house fires busting doors down to get out that it's just old news now.
Get real, fires DO happen and kids die in them. When a child panics, they usually ball up in the fetal position.
I wasn't being glib or joking. I've run in to a burning building to drag people out then gone back in to find their child. I only did that 1 time. And I'll never do that again! The smoke almost got me.
And that's when it hit me that I could have been the one to die.
Go look at the doors again. Its a solid door with no hinges. Still think a small child could get it open? They couldn't even get near that power cut-off. It's 7ft off the ground.

Food for thought, anyway.

[SenKat]

Dude - SERIOUSLY ? Not going to ruin this incrediblly talented 'Ible - not even to counter argue with your "salient" points...The author deserves a helluva lot more respect than that ! If I understood the time frame here - HE IS THE YOUNG KID IN THAT HOUSE ! And moved out (was it 4 years ago ?) and comes back to visit his cool door...I mean his parents ! No, "dr Who" I am not slamming, stabbing, trolling, whatever else may pop into someone's head - simply congratulate the inventor for his wonderful idea, and move on ! You "made" your point - and he covered every one of your concerns a lot more polite than some on here have done when being attacked by Sam Safety. Anyways - whatever - I think it is an awesom project, wish I had the ability to do it in my house, but I don't really wanna try mudding a wall from a powerchair...talk about ASKING for trouble !

[SenKat]

BRAVO ! You may not have said IN the 'ible about the manual release...but I DO recall a little something like, "...Check my site for ALL the details.." To paraphrase a bit :) Hey - GREAT JOB !

[smtgr14]

There is a manual override inside the room where the system can be shut off and the air vented so the door can be opened manually.

[yankees3142]

1. How do you figure a factor of 4?
2. So you actually made a drawing of a random modification to someone elses project, yet you decided to skip the video and go right to the instructions for fear of wasting time? lol

[-=Dr.Who=-]

1. I guess you don't understand satire because I said "don't ask, it just sounds good". But if you want to get technical... There are 3 complete air lines and 1 ram that you wouldn't have to buy and install. That's 4 components. So, factor of 4, per-say.

2. I didn't make a drawing. It says "PM me and I'll send you a drawing of the modification". Meaning I could draw it up, not that I drew a picture for him.
&
"These are just some things to think about." You must not have read that last line...

And I did watch the video, after I read threw it, but all the suggestions I made are based on first-hand experience with the different technologies involved with the controls and mechanics of automated doors.
And as I said, the video wasn't all that useful. it just showed the final product in action but it didn't show the build process. But he had a lot of nice pictures that did. So watching the video first wouldn't have given me the information I was looking for.
Just because something is at the top of a page, doesn't mean you HAVE to start there. It's just a suggestion.
So thanks for trolling.

[illuzion001]

Amazing ingenuity.

[YOUTUBEFREEKYOYO]

so cool