Wednesday, December 1, 2010

Star Trek Door

If you don't feel like reading the whole post, feel free to just watch the video!

>> Edit:  I just posted a new "extended version" of the video.

>> Edit:  Be sure to check out and vote for my Instructable in both the Humana and Craftsman Tools Contests starting next week!

I haven't posted much recently because I'm working on a few projects that aren't complete yet and I would rather wait to post them after they're further along.  But in the next few posts I'm going to be digging up an old project I finished over four years ago, which I am going to enter into the Craftsman Tools Contest.  I'm also going to talk about my ongoing work on the project, trying to turn it into a viable product. 

When I was younger, one of my favorite shows to watch was Star Trek: The Next Generation.  I also visited Disney World about once a year with my family, and my favorite "ride" has always been the monorail.  It is just an icon of all that is futuristic.  To think that it was built almost 40 years ago is amazing. 

The USS Enterprise Bridge

Walt Disney World Monorail

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.  Only one problem:  I was still in school and still lived at home with my mother in New Orleans.  I had tried to convince her for years that installing a Star Trek Door would be a good idea, but it never happened.  It wasn't until we were renovating our house after Hurricane Katrina that she finally caved in.  There wouldn't be a better time to do it. 

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:
  • Small air compressor with tank from Home Depot
  • 32" wide, solid wood door from Home Depot (to be cut in half)
  • Pocket Door Track from
  • Two 16" stroke, 3/4" bore pneumatic pistons from
  • A 5-way, 12V solenoid-operated valve from
  • Various pneumatic hose, fittings, a regulator, push-on hose connectors, two valves for air supply and purge

Here is the site of installation, where I had already started busting out the 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. 

The track only came with one pair of rollers, since normal people only put one pocket door, not two, on the same track.  Luckily McMaster sells the rollers individually, so I ordered another set.  With some additional metal L-shaped brackets to reinforce the wood, the second door gets installed.  I also started adding electrical boxes for light switches that would need to be moved out of the way. 

By this point, the hallway outside my room was a mess, with cracked drywall from my not-so-elegant crowbar and sledgehammer stud removal process.  Carpet was about to go down in the hallway, so it was time to patch things up on the outside.

Some strips of drywall, mud, and trim take care of the hallway with no problem.  Of course you know what the keypad is for.  It was one of those things I had laying around from back in the day when Radio Shack was actually cool.  After about 8 years, I had finally found the perfect application for that piece of alarm equipment I purchased for no reason. 

With steady progress, the project is starting to take shape at this point. Now it was time for some of the details to come together.  I welded up a bracket out of some steel flat bar 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. 

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. 

With the mechanical side of the project functional now, it was time to work on the electrical a bit.  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 added two 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. 

Around this time, the doors were starting to move under their own power.  The solenoid valve required a minimum of 30 PSI of air to activate properly, and with nothing limiting the flow of air, the door motion started out very violent.  Occasionally they would even cause damage to themselves from such rapid movement.  I also had to add a flow control to each individual piston in order to tweak the doors to meet in the center at the same time. 

I took a few videos around this time showing the doors moving in the exposed wall.  Sorry for the horrible video quality.


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. 

The key switch has three positions:  Hold Open, Hold Closed, and Normal Operation.  Normal operation means the door will open when the inside or outside buttons are pushed, and close after a few seconds.  I wired up the keypad so that I could lock the door from the outside, and a #* combination opens the door.  The keypad also has red and green lights which I used to indicate the door's status.  If the door is locked, the red light turns on, and the green light illuminates when the door is open.

And that just about wraps it up.  Four years later, the door is still up and running, and I recently took some photos and video of it in action during my last trip back home.  I also decided to upgrade the air compressor to a new Craftsman 1HP model with a much higher SCFM for faster refilling.  The compressor is hung from a roof beam in the attic with padding to dampen any vibrations.  


Watch the quick video:

And the extended version:


  1. You're officially my hero for this.

  2. But can you hack the keypad to get in unauthorized like in Stargate?

    Seriously though, that's an awesome build. I'd totally do that, except for the fact my parents would kill me and my wall is the wrong shape (the door is right at the end of a wall section).

  3. That's really Cool.

    Do you have a way to open it if the power goes out?

  4. Had you considered using a linear actuator instead of pneumatics for driving the door? It might offer more precise control over the speed, assuming you could find one with the right specs.

  5. The compressor in the attic seems like it would be loud, although I suppose it is above the ceiling insulation. How bad is it from below, and how often does it cycle on?

    Excellent build!

  6. What happens if you're between the doors when they are closing. Can the force of the doors closing hurt you?

  7. I couldn't find the pistons, valves, or pocket door tracks on McMaster. Could you post links?

  8. That's the most awesome thing ever. Definitely doing that once I own my own place.

  9. Cool door, but...

    Is anyone else concerned by the fact that a header and studs were removed from a load bearing wall? It's not going to be very cool any more when the ceiling starts to sag.

  10. Jarrod, thanks for the comment. Removing studs is always a concern. Being that there is a hallway right outside the door, there are a lot of walls nearby and they actually intersect the double 2x4 that spans across the ceiling by the door. I am not recommending that anyone do this to their house without doing a little bit of engineering and research first. This was just a fun project and it turned out great.

  11. dude, this is awesome! Amazing. Now if only I could get off my butt and actually make one myself.

  12. I'm seriously considering installing one of these. I just had a couple of questions. How is the pneumatic system hooked up? While I am a computer science major, and have a lot of experience with embedded electronics, I have had no experience with pneumatic systems of any kind. I was thinking of all sorts of configurations of regulators and valves, and couldn't think of a way this was designed.

  13. This is fantastic. I am finishing out my basement and moving my Star Trek room down there so this could not have come at a better time. I think I will use a flat door and paint it with a metal paint to make it look a little more authentic.
    thanks for sharing

  14. @Marc

    If it ever becomes an issue you could always install a laminated beam above the door and carry the loads completely outside the footprint of the door.

  15. Simply awesome build! You could use a PIR (Passive Infrared) to trigger the door to open as you approach it and I think that would be awesomer.

  16. Marc: How much research did you do before putting everything together? It seems like you have an incredible breadth of knowledge.

  17. @Jason: Thanks. I actually built the whole thing about 4 years ago, so it is probably one of my least sophisticated projects. Looking back on it, I could have done so much better with a little more planning. But it turned out alright, and it still works 4 years later with no problems at all.

    @Alex: The pneumatic system is very simple. The pistons are double-acting, meaning they accept air in the front and the back. The air supply is fed into a 5-way solenoid valve, then split equally into each piston. When turned on, the pistons extend and the doors open. When turned off, the pistons retract and the doors close. The electronics control everything else from there.

    1. Wow your amazing man. if its ok would you be cool teaching me some of your technique. On how to go about doing that. im 22. and i would love to learn man. My email and i do alot of things as in shooting , editing , videos and creating some 3d stuff as well. here one of my video

  18. I love it, especially the use of the PIC, that will allow all kinds of experimentation with the control. Like, maybe use ultrasonic sensors in two different planes to detect actual movement toward the door instead of by the door.

  19. Could you please post links for parts that your ordered from

  20. As an eternal Star Trek fan, beginning from the original '66 series through the motion pics, STNG, Deep Space 9, Voyager and by far the best series, ENTERPRISE and now through the New Motion Pic, I had always wondered why nobody would think of manufacturing the quintessential Star Trek doors!
    Well, obviously you were on the same wavelength and did build a great working set of doors!
    I'm wondering if there's a simpler way to do this without the need of the air compressor. It would be great if someone came up with a set of renovation doors that actually would have the mechanics/electronics mounted above the doors. If purchasing standard height doors, for example, the installer would cut out an additional 12 inches above the doors which would house all the hidden magic.
    I think there'd be a huge demand for this type of renovation project and what a great idea for the handicapped!!!

  21. I want one of these! How much cost to make this door?

  22. You should replicate this for the elderly/disabled.

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  24. dude you should patent this ASAP if it hasnt been done already. If a company decides to produce doors like these later in life you'll be sittin pretty for nothing...:)

    If you need help figuring out how send me an email or contact a patent lawyer...

  25. How long did this take to build and how much did it cost all together? I'm seriously considering building this door in my home.

  26. This is seriously awesome! I did a mini version of this (minus all the complicated PID micro-controller). I have to do a poster about pneumatic actuator in my actuator drive class and I chose to do sliding door drive using pneumatic system. If it's not too much for you, can you email me blueprint of this (or the schematic of the whole system)? Credit goes to you of course. =) This is nothing major though..just a class assignment. Hope you don't mind.

  27. Very cool, and it even sounds right!

    I'd love to build a door like that but don't really have any place for it.

    I seem to recall during the filming of the original series someone was building a new "modern" apartment complex and asked Mr. Roddenberry how they made the doors work on the Enterprise. The response was it was two guys behind the wall.

    You made it work for real! And being that one of the major expenses is the compressor if you had multiple doors they would be cheaper because you only need one compressor.

  28. That is awesome! I just have one question. I stink at coding! What was the code that you used for the micro controller? Can you also define the variables? thx.

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  30. This is fantastic! Like everyone else who's commented, your "grand eureka!" made me think of where I could build one of these doors in our family's homes...maybe a door could go up?! In my grandparent's old home there is a doorway on the 1st floor which opens to a standard staircase leading up to the second floor. When you reach the top of the stairs you actually walk alongside the staircase area to enter the center of the room (there's a railing around the staircase and that area is basically dead-space on the second floor all the way to the ceiling). I bet I could rig that door to shoot up instead of split-doors, moving side-to-side... This is probably my only option until I buy another casa... You make a good point, the fact that your bedroom door meets the hallway and has other supporting beams at the intersection is a bonus. PS: This is a fine example of engineering, professing and craftsmanship! Thank you for sharing this in such detail.

  31. I need a head constructed using the design from the prototype I built.

    LOVE LOVE LOVE your work.

    Please email me as soon as possible at

  32. That door is just... WHOA! The room should be equally fit for the theme!

    Raphael Jeanfrancois

  33. Where can I buy the Star Trek Door Kit?

  34. @Marc , Would you consider building that circuit for a price? I am in the stages of renovation and would love to add this feature. If possible could you email me @


  35. These are actually wonderful some ideas in the blog. You have touched good quality points here. In whatever way continue writing.

  36. That seems to be a fairly unique and innovative sliding door design and not too difficult to install (for d-i-y-ers). Great door, interesting sound effects (Kirk out!)
    There is a different kind of retractable sliding door at


  37. Regarding all aspects the blog was perfectly nice.
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  38. This comment has been removed by the author.

  39. I'd be trampled if all sites gave articles like these awesome articles.

  40. I found this blog worthy to read and I would love to appreciate your efforts in making the Star Trek door, no doubt you have done a great job.
    Click Here

  41. AWESOME!!!
    Is there any way to add in a safety feature in case there is anything in the way?

  42. It's a great news! i'm watching about developing of your ideas for long time! I wish you good luck.