Introduction: This Old TARDIS

About: I'm an Electrical and Computer Engineering Professor at the University of Kentucky. I'm probably best known for things I've done involving Linux PC cluster supercomputing; I built the world's first back in ...

Been traveling through time and space in a little-but-bigger-on-the-inside blue box? Kind of wish you were?

Well, a couple of decades back, I built a mobile TARDIS as part of a Halloween costume. For a while after that, it served as an actual phone booth in my basement party room... and then it spent over a decade disassembled in my garage. Recently, my daughter discovered Dr. Who and became mildly obsessed with the blue box parts sitting in the garage. So, my TARDIS lives again....

Of course, TARDIS chameleon circuits don't really get stuck; the Doctor's TARDIS has changed size and shape pretty significantly over the years. My TARDIS looks most like the one the 4th Doctor used, but it's a simpler design and quite narrow... because, much like Daleks, this TARDIS can roll through standard doorways (and could be stopped by even a single stair step). Her dematerialization circuit doesn't quite work, but she can collapse to just 2 dimensions, so this TARDIS can be transported inside mundane earth vehicles like my now-long-gone Volkswagon Golf. Come to think of it, my TARDIS actually has traveled through space and time... which is to say it's gotten older. She is actually in shockingly good shape for her age, but I've recently taken the opportunity to upgrade her a bit and add a few things no TARDIS should be without -- like the key and lock described in steps 11 and 12.

There are better examples of Gallifreyan technology out there, but this old girl is more mobile, cheaper, and can literally be built in a day. So, if that's what you seek, read on.... If not, see you later, or maybe it was earlier?

Step 1: Things You'll Need

This TARDIS is really easy to make, but it doesn't just self-assemble from star dust. Read all steps of this Instructable before you build, or even buy materials for, anything. There are a number of dimension choices that you can freely tweak, but you need to keep things consistent across steps. Here are the main materials you'll you'll need:

  • Two 4x8' sheets of 3/8" OSB (3/8" plywood would look better, but even thinner hardboard or paneling could be used instead... the shell of real police boxes was made of cast concrete)
  • One ~8' length of 4x4" construction-grade lumber
  • One ~8' length of 2x4" construction-grade lumber (stud)
  • Two ~6' lengths of 2x2" construction-grade lumber (or a 2x4" ripped down the middle)
  • Four flat-plate-mount rolling casters
  • Hinges for the doors (e.g., 4 regular hinges)
  • A small handle for the right door
  • Assorted fasteners and glue
  • Blue semi-gloss latex interior wall paint
  • A light for the top (be creative; the light shape and size has varied a lot)

These are mostly commodity supplies, so pricing varies. However, your total supplies cost should be under $100, and probably closer to $75. I think it was more like $30 when I built mine....

Tool-wise, you obviously need something for cutting the lumber. You'll also need a way to make the slots (dados) -- a router or nibbling with a table saw. And you'll need a drill. And stuff for applying the paint. And a printer for some artwork we'll also be applying.

A 3D printer would be nice for making some optional parts, the designs for which are all posted at Thingiverse asThing 695039. And you'll want a laser cutter to cut the 4x8' sheets. And maybe Rassilon's Eye of Harmony as a power source? Now that I think about it, you want a lot of stuff. Go try to convince your parents or significant other to let you buy it all. They said no? Hey, it was worth asking. Ok, now go back and just ask for the stuff you actually need -- like just the 3D printer. ;-)

Step 2: Your Route to Success

Routing a slot into the base and top is a critical part of this design. It's the key to making the TARDIS able to collapse into 2 dimensions and be reassembled in 3D dimensions in literally a minute or two. The slot tolerance need not be very tight, because gravity is on our side, but mine were cut with a router that ensured they were a very firm fit and that's certainly not a bad thing to do.

If you own a router with a 3/8" straight bit and an adjustable fence, it's pretty easy to cut the slots either before or after the base and top boxes have been assembled. However, it can be easier to do it before you've even cut the 2x4" and 4x4" pieces to length -- especially if you make the fairly harmless simplification of making the slot the full length of the pieces, so you just cut one continuous slot for the complete length of the lumber. If that's what you want to do, now is the time:

  • Take the 2x4" stud and route a slot of at least 3/8" width and 1/2" depth.
  • Take the 4x4" post and route a slot of at least 3/8" width and 1/2" depth.

Now cut the pieces to make the 27.5" per side square box shapes shown. Actually, it's not critical that it be 27.5", but it can't be much bigger than that and fit through a standard doorway that still has a door hanging on hinges in it -- although 30" or wider doorways are common, be warned that some homes have doorways as narrow as 28". The critical dimensions are that the slots end up with outside dimensions that match the pieces cut in the following step. Mine are 24" wide and 24"+2*3/8" deep, but you might find it easier to make it 24" square by making the side panels 24"-2*3/8" wide. If you cut the slots first, you'll also probably want to make 45-degree cuts for the box corners, but if you route them after assembly, you can just butt the pieces together at 90 degrees in the corners. It doesn't matter much, and any joinery will do.

That said, the strength of the 4x4" base is really critical to the stability of the TARDIS. I'm a big fan of biscuit joinery, but my TARDIS also has each internal corner braced with a steel "L" bracket screwed-in using drywall screws. Feel free to be a little paranoid here; the completed TARDIS weight is around 100 pounds, and you don't want a base that can't handle the load.

Step 3: Measure Twice, Cut Once

Ok, measure carefully, but there are more cuts than one left to make. These are not fancy cuts, and all could be done with just about any kind of saw, from a handsaw or jigsaw to a nice table saw... use whatever you have that's most appropriate for each cut. Most lumber stores will even make cuts for about $0.25 each on a big panel saw, which could make it easier to get the lumber home.

Let's start with the 4x8' sheets. Cut the following pieces:

  • One 24x72" panel (back)
  • Two 24x72" panels (left and right side) -- alternatively, as discussed in the previous page, make these panels be 24"-2*3/8" wide, or 23.25x72"
  • Two 12x64.75" panels (left and right doors)
  • One 24x24" panel (roof)
  • One 24x6" panel (front sign board)

The 12" wide door panels, and 24" roof panel, can actually be slightly undersized (e.g., by the width of your saw's blade, or even more if you adjust the slot dimensions in the previous step) if that's more convenient for fitting things into the 4x8' sheets... or whatever scrap material you're using. Just try to keep the dimensions consistent. The back panel is now done, and should look like the image (except probably not yellow).

The remaining cuts are simply trimming the two 2x2" pieces to length: about 70.5".

Step 4: Assemble the Sides

The left and right side pieces actually get the doors permanently fixed to them. As everyone knows, even though the sign on the front of the TARDIS says "pull to open," the doors actually push in to open. Thus, the hinges actually sit on the inside of the TARDIS and each door folds in nearly flat against the side it is mounted on. We also need some kind of cleat to bolt-together the sides with the back, and by permanently attaching that cleat to the side, we also produce a little bump that protects the folded-near-flat door when stacking the side panels for 2D transport. That is less confusing if you look at the images....

Start assembling the doors by attaching a 2x2" flush with what will be the inside back edge of each side panel. It should be vertically centered 3/4" from top and bottom of the side panel. I used carpenter's glue and drywall screws to attach the 2x2" cleats -- and screwed through the OSB panel into the 2x2" for greater strength. The truth is that the glue alone is probably plenty strong, but again the TARDIS is heavy enough that it could hurt somebody if a piece were to fall apart.

Mounting the door on the side panel is fairly straightforward too. Lay the side panel flat with the 2x2" cleat on top (inside facing up). Position the door panel in what would be it's closed position (standing up 12" tall), flush against the edge of the side panel a hair more than 1/2" up from what will be the bottom edge of the side panel. Position your hinges in the corner formed and screw them into the side and door. You are screwing into 3/8" material, so the screws can't be very long, but the door isn't very heavy and a couple of standard hinges proved more than sufficient for each door of my TARDIS.

The resulting side assemblies should look like the images here, except they shouldn't be green and red. That coloring is just for distinguishing the pieces in the assembly images.

Step 5: Assemble the Top

The 2x4" box is actually the frame for the top of the TARDIS. Just as the slot in the 4x4" box will hold the panels together at the bottom, the slot in this will hold the panels at the top. In fact, gravity and the top and bottom slots are most of what will hold the completed TARDIS together.

Lay the 2x4" box flat with the slotted side face down. Screw and glue the 24" square top panel centered on top of the box to form the roof. Note that this roof adds a lot of strength to the 2x4" frame, which is why I don't think we have to worry about bracing the corners like I did for the 4x4" base frame.

The front sign board for the TARDIS simply gets stuck into the front slot. You could leave it a friction fit, but again, I prefer to avoid giving the TARDIS opportunities to have pieces fall off and hurt somebody, so mine is screwed and glued into that slot.

Depending on what kind of light you decided to mount on top of the TARDIS, this might also be the time to add mounting hardware or a platform. Battery-operated round lights intended for lighting closets are widely available for less than the batteries that will power them; they are probably the simplest type of light to stick on top. However, they're a bit short. Thus, my TARDIS was built with a little 1.5"-tall 5.5"-diameter platform on top to boost the height of the light. Actually, I also put an identical light on the inside of the TARDIS to facilitate use as an actual phone booth... because otherwise it gets dark in there. We'll talk about some other lighting options later, but keep in mind that you don't want a light on top that's tall enough to hit the door frame when rolling the TARDIS through a doorway.

Step 6: Test Assemble the TARDIS (without Wheels)

Ok, you've got all the pieces now, so you should be able to assemble the TARDIS -- as shown in the images.

It will probably take two people to assemble it at this time, because the sides and back are not being held to each other by anything other than the slots in the base and top. It's easiest if one person holds the sides and back in the base while the other fits the top on. Depending on how tight the slots are, you might need to tap things into place. Disturbingly together, isn't it?

Well, the reason you were doing this test assembly was to check fit (and if something didn't fit, now is when you discover that and fix it) and to ensure alignment for the holes to bolt it together. Yeah, the bolts are a bit paranoid, but again, I don't want pieces of the TARDIS falling off.

With the TARDIS assembled, drill holes from the back through the side-mounted cleats for some bolts. I had always expected to use 3 or 4 bolts per side, but 1 or 2 bolts seems to be plenty -- perhaps because pulling the back panel against the cleat forces accurate positioning. In fact, I'm currently using just one 1/4-20 bolt to secure each side piece. When reassembling the TARDIS, this greatly simplifies things because as soon as a side panel and the back panel have been put in place, you can simply bolt them together to be self-supporting for the rest of the assembly process.

Step 7: See Blue

Now that we know everything fits and nothing needs to be sanded or shaved to fit, we can disassemble the TARDIS for painting. It is much easier to paint with the panels laying flat than standing in their upright, paint-trying-to-run-down-the-sides, assembled orientation. The uneven surface of OSB panels can be painted using a roller, but filling the low spots usually takes a little extra paint, which makes runs even more likely if the panel isn't horizontal for painting.

There is only one color for a TARDIS, and it is blue. Unfortunately, there is more than one blue. Officially, the BBC tells us the TARDIS color is Pantone 2955C -- but that's obviously much darker than the 4th Doctor's TARDIS, which is a much better match to the official color of the University of Kentucky, UK's PMS 286. It is completely coincidental that I'm a Doctor spending a lot of time in the UK, but am not from around here, and that my TARDIS has been that shade of blue ever since it materialized. To be completely clear, I'm a not an MD, but a Ph.D. and Professor of Electrical and Computer Engineering at the University of Kentucky, and my research certainly doesn't involve wibbly wobbly timey wimey stuff (as far as you know). So enough about that. Anyway, you need blue paint, and I'd recommend a semi-gloss latex interior wall paint. Stock colors for wall paint usually don't include anything very appropriate, but you can get one custom mixed in most stores that sell paint. The color of the BBC TARDISes have varied over time even more than the size or shape, so feel free to pick whatever precise shade of blue appeals to you, even if we all know the TARDIS is UK blue.

I didn't paint the inside of my TARDIS, but perhaps you should to seal the wood and dress it up a bit? A very light gray with bright white circles on it would probably be most appropriate for a TARDIS based on the design from the 4th Doctor, but there are many different control room styles, so you could pick any style. I guess I picked the control room with raw wood on the walls.

Step 8: TARDIS on Wheels

What could be better than a TARDIS on wheels? Well, you can't have that, so a TARDIS on wheels will just have to do.

Flip your 4x4" base over and screw-in the wheels near the corners. If you really wanted to, it wouldn't be hard to sink the wheels into the base so that the TARDIS doesn't sit quite as tall (and you'd never see an occupant's feet, which can sometimes be visible under the TARDIS, because this one doesn't have a floor). Actually, it also wouldn't be hard to put a floor on the bottom. However, the lack of a floor allows one to stand inside and move the TARDIS about, which is kind of cool. Also, having 1.5" ground clearance really helps if your TARDIS must translate through space that is covered with a deep-pile carpet.

You should now be able to reassemble the TARDIS in a minute or two and be able to freely wheel it around.

Step 9: But It's Just a Blue Box

Well, yeah. It is just a blue box... on wheels. So, let's print some stuff to dress it up.

Real police boxes, and BBC TARDISes, have much more 3-dimensional trim than our simple blue box. The roof is stepped and/or sloped. Each door has four raised panels, there is framing around each piece of glass in the windows and each sign, and the corners are built-up. All that would add a lot of weight to the TARDIS, increase material costs, and honestly still not result in a prefect BBC TARDIS replica. Thus, our blue box has none of that... but you could easily add it by painting appropriate shadow patterns. Had I built this TARDIS using something smoother than OSB, I probably would have painted a realistic pattern on it. I didn't.

Instead, you can get a pretty decent approximation by printing a few things to apply to the surface of the TARDIS. Originally, I had painted the top sign on by hand and glued-on printed window patterns; the hand-painted top sign looked too imperfect and the laser-printed window patterns looked too perfect. Thus, I created the images here as upgrades of the original labeling. Printed-out on a decent color inkjet or laser, these bits can be trimmed with a pair of scissors and then stuck on the TARDIS using a glue stick. Really fast and easy.

Notice that these three are the only things I printed and applied to the TARDIS. You could also print the St. Johns badge that is seen on the right door of some of the BBC TARDIS versions, but the 4th Doctor's TARDIS didn't have that sign. It would also be possible to print panel shadow patterns to greatly improve the appearance of the TARDIS, but that seemed like just too many bits of paper to stick together. Keep in mind that applied paper isn't super durable, so don't get it wet, etc.

Step 10: But Where's the Handle?

The handle goes on the right door, of course.

This isn't a critical feature; I simply used a cheap plastic drawer-pull handle.

Step 11: But Doesn't the TARDIS Have a Key?

Of course you need a TARDIS key!

There's a lot of stuff on the WWW about TARDIS keys. Apparently, the first couple of Doctors had ordinary Yale lock keys, but the 3rd Doctor is later seen with a spade-shaped silver key. The 4th Doctor actually had a variety of different styles of keys, but the spade-shaped one is the one most folks remember. Later Doctors tended to have the Yale-style keys, although the 7th Doctor had a fan-shaped one and the 8th Doctor again had the spade-shaped one. In any case, it seems the spade-shaped design is what would be most appropriate for our TARDIS, and my design is a fairly accurate model of the real thing made using trace2scad (a free software tool I wrote to convert images into OpenSCAD polygon models) to process photos of the actual BBC prop. You can buy spade-shaped TARDIS key replicas from various folks online, but of course we'll make our own. After all, a Doctor not making their own TARDIS key is like a Jedi Master not making their own light saber....

The particular design here is to be 3D printed. If you don't have a 3D printer, simply use your TARDIS to skip forward a few years to when everybody has one. Or maybe you can make one by hand from this design?

The construction process is:

  1. The key prints in two parts, a top and bottom, using a 3D printer. I used my MakerGear M2, which is a great printer, but just about any PLA-extruding printer can handle this design. Feel free to use a smaller extrusion to get finer detail, but I used 0.25mm with a very standard gray PLA.
  2. Line-up the two pieces back to back and glue or weld them together (e.g., by lightly melting the edges together using a soldiering iron).
  3. The printed parts look a little rough, which you could remedy by tricks like using thinned wood filler to smooth the surfaces; I didn't bother smoothing it. However, I wanted the key to look like beat-up old metal. I used a light coat of silver spray paint followed by a thin wash of black latex to simulate tarnish.


Step 12: If There's a Key, There Must Be a Lock

It does make sense that if you have a key, you should have a lock. My TARDIS originally didn't have a lock (as you can see in the photo at the start of this Instructable), but it does now.

You see, the problem with the creative key design is that no standard lock mechanism really matches it. No problem; we'll just make our own using that 3D printer you either have or went to the future to borrow.

The lock consists of four 3D-printed pieces extruded out of gray PLA plastic. The stationary outer lock barrel traps an inner lock barrel that can freely rotate, and the two print as an assembled unit. The front of the TARDIS key fits into the front of the inner lock barrel to provide a handle by which the inner barrel can be rotated. The back of the inner barrel has a little notch that fits the bar that pivots into a catch on the inside of the left door to lock the doors shut. The bar is printed as a separate piece because we'd otherwise have a hard time getting it through the hole to install the outer barrel in the door; once the barrel is installed, you simply glue or weld (with a soldering iron and some spare PLA filament) the bar into the slot for it on the back of the inner barrel. The only part of the lock on the left door is the catch that simply traps the bar against the door.

The construction process is:

  1. Print the lock parts using a 3D printer. I used my MakerGear M2, which is a great printer, but just about any PLA-extruding printer can handle this design. Feel free to use a smaller extrusion to get finer detail, but I used 0.25mm with a very standard gray PLA.
  2. The printed parts look fine, but they just don't look like beat-up old metal. To remedy that, I used a light coat of silver spray paint followed by a thin wash of black latex to simulate tarnish. This was only done to the front of the barrel assembly, and care was taken not to build-up paint in the gap between the fixed outer and rotating inner barrels.
  3. Drill a hole in the right door of the TARDIS sized to firmly accept the cylindrical part of the outer barrel.
  4. Push the barrel assembly into the hole in the front of the right door so that the beveled portion of the outer barrel sits flat against the front of the door. The inner barrel should still turn freely after mounting.
  5. Push the bar into the slot in the back of the inner barrel and glue or weld it in place. It should now freely pivot with rotation of the inner barrel, but will hang straight down due to gravity providing a default "unlocked" position.
  6. From within the TARDIS, behind its closed doors, pivot the bar horizontal across the inside of the left door. Position the catch on the back of the left door so that the bar rests in it and is supported by it. Fix the catch to the inside of the left door in this position.

That's really a lot easier than it sounds. Anyway, you're done now.

To open the TARDIS from the inside, simply lift the bar and pivot it to fall pointing down on the back of the right door. The pattern on the inner barrel will match the key with the keychain hole at the top if the door is locked, and will be sideways if the door is unlocked. To open the TARDIS from the outside with the key, press the front of the key into the pattern on the front of the inner barrel and use the key to rotate the lock clockwise, lifting the bar out of the catch and letting it fall into the pointing downward open position. To lock the TARDIS from the outside, insert the key and turn counter-clockwise. If you need to get into a locked TARDIS without a key, simply slide something thin between the doors and use it to push the bar up... this isn't a difficult lock to pick or to force, but at least it looks odd enough that people might not immediately try either approach.

Step 13: But It Isn't Bigger on the Inside

Oh yes it is.

Simply print (either 2D or 3D) the word "Bigger" and hang it inside the TARDIS.

Sure to get the appropriate "Why is it bigger on the inside?" question....

Step 14: But What About the TARDIS Sound?

Glad you asked about that.

Originally, my TARDIS contained a little tape recorder that would be set to play a tape that contained randomly-spaced recordings of the TARDIS dematerialization/rematerialization sound. That was OK, but we can do so much better now.

Got a cell phone? Of course you do. (A fact that does call the utility of building a phone box into question, but you didn't think of that earlier, did you?) You should have no trouble finding a free recording of the TARDIS sound, which I suggest you install in your cell phone as a ringtone. I set mine so that it would only use that ringtone for a text message from my daughter. During my daughter's birthday party, my cell phone was left sitting on the TARDIS roof behind the light, and my daughter simply used her cell phone to text it whenever she wanted the sound. Presto: remote control TARDIS!

It wouldn't be much harder to also use a cell phone to also serve as a flashing light source for the fixture on top of the TARDIS roof.

Step 15: Is That All There Is?

Of course not; there's quite a bit more we can make.

I'll be adding to this later. For now, you'll just have to wait... or get in your TARDIS and come back when everything has been posted.... Enjoy.

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