Introduction: Build a Star Floor

Picture of Build a Star Floor

Where it all started

I wanted something a bit geeky for the house, and I found fibre optics! Using them is very simple, but the results can be great - so once I'd completed my star floor in the bathroom I got hooked, and you'll see at the end of this Instructable some of the other things I've made using fibre.

It is all based on this project by a nice bloke call Andy:

Fibre optics sound fancy, but what I've used here is just a rod of plastic (PMMA) that looks a little like fishing line. If you shine light in one end, it comes out of the other. The useful bit is that you can bend the fibre, and the light still comes out of the end - creating a point of light - or use several and you have stars!

In just a few simple steps I'm going to show you how I built the star floor. Before starting on the actual 2.5 x 4m bathroom floor I decided to do a trial, and would highly recommend this step, as it gives a good idea of what you are going to have to do (and why) in terms of grouting and fibre management. I used an offcut of MDF as my sample floor, and the smallest cheapest adhesive and grout I could find, along with some fibre, and a makeshift light source. The demo took a few hours to build, with all the fiddling, as well as time in between for the grout and adhesive to set.

You'll also see a capacitive switch I tested, with a view to hiding it behind a wall tile to control the floor by waving your hand in front of the switch.

Step 1: Gather Your Equipment

To complete this project you will need:

  • A floor
  • Fibre
  • A light source
  • A gland
  • Scissors
  • Hot knife
  • Sparky tape/cable ties
  • Everything you need to tile a floor - Tiles, tile adhesive, grout, a float, a squeegee, etc

And lots of time.

Step 2: Make a Plan

First thing's first, you need to decide where your light source is going to be, because all of the fibres need to run from this point.

The light source you use ( )

) is likely to be mains powered. For safety reasons, place your light source somewhere outside of the bathroom. This should make the whole bathroom installation safe, as all you've done is weave a bit of plastic into the grout, there is no electricity required inside the bathroom for the floor. In my bathroom, I fed the fibre bundle under the doorframe and up through the floorboards of a hallway cupboard, so I could put my light source in there.

Once you know where they're starting from, you can begin to run your fibres.

Step 3: Don't Lay Tiles Like a Pro

Picture of Don't Lay Tiles Like a Pro

Conventionally, to lay floor tiles you're supposed to start from the centre line, and head toward the walls. However, for this floor each fibre needs to end up at the same place, so tiles need to be laid from there. This is unlikely to work with a conventional centre line floor tiling method.

Bundle your fibres

The first thing you need to do is decide how many fibres you want per square metre of floor and create a bundle of fibres, making sure each strand is longer than the path to the furthest point you want it to reach. So if the furthest fibre from your light source is 4m away, cut the fibre at least 30cm longer. Cable tie the bundle tightly, or use sparky tape (more secure, but harder to remove) at the end near to where you'll attach the light source.

If you're covering quite a large expanse of floor, you might need to use smaller bundles that then come together to meet your light source. For my floor, the fibres are in bundles to cover about one square metre with stars - so we have several bundles made from fibres of a single length (i.e. 4m), as they'll all be cut anyway.

Place your fibres under the tiles

The first tile that goes down will have to be the one nearest the light source. This is because when you float the adhesive onto the floor, you'll be scraping the floor, so you need it to be clear of fibres. Start laying your tiles, spreading your bundle of fibres out underneath the tiles as you go.

You'll see that even for a relatively small area, the fibres become a noticeable lump. To keep the tile height even, spread the fibres over the floor, roughly in the directions they'll need to be heading. You have to be very careful about the entry point for each area of fibre, as the first tile will have every fibre in the bundle underneath it, which could mean it doesn't have much floor to stick to! As my floor was so big, we routed some of the fibres around the edge of the floor, so our bundle of fibres split into three before it entered the tiles, to make sure there weren't too many fibres under one single tile.

Step 4: Peel, Adhesive, Fibres, Tile.

Picture of Peel, Adhesive, Fibres, Tile.

Once the first tile is down, lift all the fibres up, and peel them back out of the way, keeping hold of them (this is where I found a friend particularly useful!). Adhesive the floor for the next tile. Lay any fibres that are heading under the next tile back down, being careful to leave plenty of floor exposed. This gets easier as you get further from the main bundle. We found it easier to spread the adhesive this way, one tile at a time, because of the fiddliness of managing the fibres too.

Anywhere you want a star to appear, stick a fibre up between the tiles. I used tape to hold the fibre roughly in place whilst I continued to lay more tiles, although it was only mildly effective and did come unstuck - but this doesn't matter so much once the next tile is down. Try to make sure that the route of the fibre means that when it surfaces, it is perpendicular to the tile edge, sticking up as vertically as possible. This will mean the fibres will be easier to hide, as well as grout and lay.

This process of peel up fibres, adhesive floor, lay fibres on adhesive keeping back intended stars, lay down tile is repeated over the whole floor.

Bends in the fibres cause light to escape, making the stars less bright, and this is especially true of the tight radius of the flat run across the floor, to the sudden upturn between two tiles. For me, 0.75mm fibres seemed like a good balance between light and bend radius.

Tiling was done with a dim light source attached, as it helps to find the fibres, but doesn't blind you when you look at them! It also highlights the inevitable damage to fibres, keeping you aware of how delicate they are. The most important thing to remember during this process is to be careful with your fibres - any breaks and you've lost that star!

Step 5: Don't Grout Like a Pro

Picture of Don't Grout Like a Pro

Once you have all the tiles down, the floor will look fairly hairy. Grouting can now begin (make sure you leave enough time for your adhesive to cure as per the manufacturer's instructions).

To grout floor tiles, use a good flat float (not a cheap squeegee thing) and work the grout into the floor area. Each fibre is both delicate and will move, so treat them with care - a conventional floor grouting method is likely to break them.

Trim any long ends of fibre to a manageable length with a pair of scissors - I left around 10cm sticking through the tiles so I could see where the fibres were for grouting. Grout the tiles between the fibres as you would if they weren't there. Then, using a combination of the proper float, the cheap squeegee, and your fingers, grout the fibre in place. It will move, leaving a hole in the grout wherever it was. Try to keep the grout neat, but don't worry too much about small holes. As long as the grout is holding the fibre in place, and there isn't excessive grout to remove, leave it. After you have done this with each fibre, you can carefully grout around each fibre a second time to fill the holes.

Create your stars!

The final trim, which will turn your fibres into stars, is the only important one. Using a hot knife (cheap soldering iron with a scalpel like bit), trim the fibre as close to the grout as possible. As the fibres are below the tile height, they won't be felt with bare feet, and as they're transparent, they're almost invisible - as long as they're short enough, and emerge perpendicular to the tile edges. Once this process is complete, grout again to be sure there are no holes. Grout is hydrophobic, and so any holes are unlikely to be big enough to actually leak, but a no holes in the grout policy is definitely the way to go.

Step 6: Light It Up

Picture of Light It Up

The floor should now be fully fibred, and when it is off, should look look any other tiled floor. So it's time to go back to the start of your bundle and light it up!

You can get ferules for terminating the fibre to the source efficiently, and the light sources designed for fibre optics have many effects to make your floor look great. Unfortunately they were out of my budget, so I used a cheap torch, running a 3W Cree LED, that focused down to a very narrow beam (with a PSU tacked in to replace the batteries). This is enough to light my entire floor, which uses about 1/2 mile of fibre in total. There are no effects, colours or twinkling, but it cost me £3 for the torch. I haven't installed the capacitive switch, but I reckon the floor costs less than £6 a year to leave it on full time.

To terminate the fibres, use the smallest gland you can get away with. A metal gland allows you to cut the fibres with a hot knife very close to the gland. Polish with a bit of with 240 grit sand paper and once dusted off, the light should be able to enter all the fibres well and evenly. Switch it on - and you have stars!

Step 7: A Floor! (and a Table) (and a Speaker) (and Some Stairs)

Picture of A Floor! (and a Table) (and a Speaker) (and Some Stairs)

There you have it. A fairly unique floor, that looks great, and is really hard to photograph.

It may have taken two of you two weeks of extra time to lay the floor, and you've broken so many fibres that you've not got the pattern you were hoping for, and people think you're strange when you beckon them into your bathroom, but it looks cool.

And if you get hooked...

I also hacked a coffee table, which is equally hard to photograph. This time the stars are arranged in the shape of the constellations visible when my son was born. Whilst off, again, the stars are pretty much invisible.

The guitar was converted into a speaker, and was also fibred. I've roughed up the fibre strings with sand paper to make them side emitting (as i didn't have any proper side emitting fibre).

The stairs are simply LEDs behind the carpet. Again, embracing the invisible when off theme.

Let us know how you get on.


mud1070 (author)2017-06-19

Approx., how many fiber runs did you lay for the bathroom project? I have a project coming up with a room of simialr size.


Baldr (author)mud10702017-11-30

I used about 1/2 mile of fibre, but it will depend on the density of stars and the location of your light source. (Sorry for the late reply.)

CraftAndu (author)2016-01-19

Wow! This is so cool, I have to try this!

VanessaH14 (author)2015-10-10

Hey, do you have a tutorial for the table? I'd love to try to something easier than the tile for my first attempt.

Althea MaeH (author)VanessaH142015-12-29

i would also love to read an instructable for the table!!

TarasT made it! (author)2015-12-28

Baldr (author)TarasT2015-12-28

That's great. Did you do anything differently? It looks really good.

TarasT (author)Baldr2015-12-28

Everything made as you describe, but modified light source and changed the place of the light source.

Light source consisting of a flashlight for 2,7 $ ( and LED driver $ 2

And light source is placed in the wall, covering with chrome decorative plate (

nflemming2004 (author)2015-12-27

For applications like the guitar strings, if you're okay with an interrupted light, you could just bend the fiber in tight loops before "stringing" them on the guitar. The bending action should break the internal glass core within the fiber, and emit light at each of the breaks.

Baldr (author)nflemming20042015-12-27

Unfortunately the fibre used here is not glass.

flyingpuppy (author)2015-12-27

Can you share what kind of fiber optic you used? I'm learning that not all fibers are the same--width, flexibility, etc. Thanks

Baldr (author)flyingpuppy2015-12-27

Hi, what have you been using it for? I used 0.75mm pmma. For smaller projects, any old fibre should be optically fine. If you buy it from UFO or Starscape then you'll get good fibre, but I think all of the 0.75mm comes from China. The bigger stuff is made here. If you want to get more technical, the mitsubishi datasheets are good, and often their fibre is specified because of them. I think all of the good manufacturers make to similar specifications, but Mitsubishi write a good datasheet! What was the problem with the fibre you used?

chriscc63 (author)2015-12-27

holy smokes this is way cool. As an architect I will want to try this for a client. It is very popular now to light the toe kick with led strips but this is far more sexy. Kudo and great instructable

Wingloader (author)2015-01-27

I'm tempted to rip up my floor that I just put down. :-)

If you have the joint-width sufficient already you could do it by just cutting the grout out and re-doing it after the fiber is placed.

eruger (author)Wingloader2015-02-01

I have heard of people running it (straight) through the grout channels of existing floors, though I didn't see a nice instructable on it, much less the final product. But if you have wide enough grout, and used flexible could possible remove the grout, leave the tile, and not have to do it all over...not sure how to handle the bends at the wall. Guess that depends on much space there is under the baseboard.

AllDayDaddyO (author)2015-07-18

This is so cool. I just installed a star ceiling and posted a reference to this instructable as inspiration.

zero1307 (author)2015-05-28

so cool

Teritaylor (author)2015-04-25

Loved the coffee table and thanks for chatting about it to me today at Maker Faire. You said you might consider an offer but I can't put more contact details on here. Reply and I'll send you an offer. I would love the table! Hope tomorrow is good, your designs are fantastic.

Baldr (author)Teritaylor2015-04-28

Thanks. Glad you enjoyed Maker Faire. I've messaged you!

Luisvieyrah (author)2015-02-13

Hello, where did you get the fiber?

Baldr (author)Luisvieyrah2015-04-28

Starscape, there is a link in the instruction.

msakosky (author)2015-02-11

I paint and detail like miniatures..This is awesome ..Can the optics work for making my mobility scooter like light on bottom or underneath pimp out my scooter .??

anyone ever do something or know someone who could ,would let me know ...This is so nice ..YOU did a wonderful job :D

borsedigaya (author)2015-01-27

Love your project, can you give some details on the coffe table? Didi you drill holes to pass the fiber optic through? I'd love to try something similar but the bathroom seems too much to cope with right away :)

dauwe (author)borsedigaya2015-02-05

Also love to see a tutorial for the table!

ValentinoD (author)borsedigaya2015-01-31

I also want to know about the desk! Awesome projects!!!

eruger (author)2015-01-30

Anyone ever tried working fibers (all-glass obviously) into low-fire ceramics? I wonder if it would work? Of course, you could use Marblex.

MaggieM5 (author)eruger2015-02-03

How about if you used something in the clay that melted away in the firing, leaving you an empty "tubeway" that you could then push the fiber into when it's cooled. I seem to remember my dad talking about "lost wax casting" where a detail for a model (train) was made in wax and then a mold was made around it then the molten metal was poured in and the wax melted away...

eruger (author)MaggieM52015-02-03

Done lost wax casting, in silver and bronze, and yep, you got the idea. Don't know how it would work with firing clay, but it's certainly a reasonable notion. I do remember seeing a sculpture that was badly cracked in the kiln because some armature sticks had been left in the clay and the swelling as they heated cracked the clay, so you'd have to be careful about your material. Also, the clay shrinks while drying, so your material would have to shrink with it. I expect that there are specific techniques for that established, actually. Good thinking :)

Forsythe3 (author)eruger2015-01-31

So, optical fiber engineer here. This should be possible. Silica fiber is heated to ~1950C during drawing, so the temperature ranges for firing should be fine for the glass.The issue is the polymer outer jacket. This starts to damage at ~120C.You can strip this off, either mechanically (knife) or chemically (acetone), but in doing so the fiber becomes very fragile, and won't bend easily.The other problem will be the type of fiber, telecoms fiber uses an all glass structure to guide light in ~10um central core, whilst illumination fiber utilises the polymer as a guiding structure, hence if you remove it it won't guide light. If you were to use telecoms style fiber and stripped the polymer you could get it to work, but you would need to use a brighter light source to compensate for only guiding a smaller fraction of light launched from a bulb type source.

Forsythe3 (author)Forsythe32015-02-02

I should probably state, you can get hold of larger core fibers that have an all glass guiding structure. Usually formed with a flourine doped glass layer around the outside. With larger cores and all glass guidance of the light, these would be the best way to go, but they are much more expensive than polymer guiding fiber, or telecoms fiber.

eruger (author)Forsythe32015-02-01

Thanks! Good answer :) The one I did look at was rated to ~350C, but I
don't recall its rated purpose. I suppose the polymer would simply burn
off in firing, letting protect the glass fiber while working it into
the clay, though this would probably leave the core running through a
channel of sooty black, highly absorptive instead of reflective. Perhaps
a bundle of fibers without cladding could fuse and since they'd take in
more light, maybe they'd transmit more? Anyways. I don't have access to
a kiln anymore :( so I thought I'd share the notion for someone who
does to try :)

eruger (author)eruger2015-01-30

I looked up a few fibers' stats, And it looks like their melt range is well below even low-fire kiln temperatures, so I guess probably not, though it could still be worth an experiment if there's any potters out there.

anilbot (author)2015-01-31

Excellent instructable... (y)
I donno' where I can get loads of optic fibre (in India), but want to try this...
I am planning to put a couple of grouping onto fibre bundles and use neopixels to light them, so that would give a chroma effect on those stars...

eruger (author)anilbot2015-02-01

I would try to find a contractor who installs it. There's always scrap from a job. I understand India's fiber network is rapidly growing.

9kaim9 (author)2015-01-28

Brilliant and beautiful. My family wants to try the bathrm floor this spring. Thanks!

Baldr (author)9kaim92015-02-01

Would love to see pictures if you do!

cfreitag sr. (author)2015-01-30

Using a small round piece of defusion plastic from an old florescent lamp and a small reduction motor to rotate it slowly you can create a twinkle effect which looks awesome. I did something similar on a ceiling a few yrs back.

eruger (author)cfreitag sr.2015-01-30

A small jar or bottle of cast glass (thicker with more ripples) works well too, though it probably takes more space.

Baldr (author)eruger2015-02-01

I do have plans for a twinkle effect, using a stepper motor and an arduino.

starphire (author)2015-01-27

These are some good examples of creative applications of fiber optics. I wanted to note in supplement to your introduction that there is actually an important difference between ordinary acrylic (PMMA) rods and fiber and optical fiber. The latter is made with an invisible outer sheath layer made of slightly different plastic, and the difference in the refractive index between the outer layer and the core is critical to keeping the light bouncing back and forth inside of the fiber instead of just leaking out in the first few inches.

It's also worth noting for others seeking to do this that if you bend plastic optical fiber too sharply (or scratch it) at some point it probably won't break but it will leak a lot of the light out at that point, so arranging the fiber where it bends up between the tiles to maximize the bending radius and taking care not to damage the sheath during installation will help bring as much of the light as possible to the end point.

A final thought about using modified torches/flashlights as a cheap light source: the LED inside these devices is frequently overdriven and thus rated for a MUCH shorter useful lifetime (perhaps 1000 hours instead of 20 or 30 thousand) than the same LEDs used at lower power or with a better heatsink arrangement (such as LED lightbulbs). The designers can do this because their expectation is that it will not be used for long periods of time, being just a portable emergency light. It will probably just gradually dim rather than die suddenly - slowly enough that it won't usually be noticed. At such a low price, you could just replace the light when it dims. But for people desiring a starfield that will be left on all the time or mounting the light source in a hard-to-reach place it may be a good idea to use something that was designed to be on continuously.

Baldr (author)starphire2015-02-01

Hi Starphire,
Just to address anyone's fears - the PMMA fibres I used do have cladding - as do any optical fibres - creating the lower refractive index required for total internal reflection. It isn’t until the fibre contacts with a surface with a higher refractive index (like fingers, sheath, tile adhesive etc.) that you need cladding. The 0.75mm stuff I used might have in the region of 0.015mm of its diameter as cladding. I believe graded index fibres have an even cleverer way of achieving this, by slowly increasing the refractive index from the core to the cladding boundary, creating a curved light path.

The sheath is simply a protective sleeve, to stop the delicate fibre being damaged. The fibre I used has no sheath. Sheathed fibre would have been a lot more robust and easy to put down, but I wouldn’t have got many under a tile before I created a crazy golf course!

The sudden upturn between two tiles does create a bend radius too tight to get all the light out of the end. There is also inevitable damage to fibres when laying the tiles. Some ended up looking much like the guitar speaker, where I have intentionally damaged the fibre. Fortunately, as you can see, despite this light loss, plenty of light makes it to the end to become a star.

The LED lifetime is an issue, as it is with most LED products. Very roughly: the torch is using less than 2.5Watts. Assuming the 2.5degreesC per Watt is badly packaged to give a 20degreesC per Watt junction to ambient, and kept in a 30degreesC cupboard, the lifetime of a CREE XM-L (which is time to 70% brightness) might be about 4 years (no failures reported). I have one year of constantly lit star floor already with no noticeable change!

Ward_Nox (author)2015-01-30

could make a neat wall decoration too

thereyno (author)2015-01-28

^_^ water proof right? interesting!! ^_^ ty!!

eruger (author)thereyno2015-01-30

Fiberoptics are made of glass and/or plastic. Impervious to water. You might have heard of rain or flooding messing up your internet fiber optic cables, but that's from condensation in connections or damage to electronic parts, and not relevant to this application.

samalert (author)2015-01-26

This is something unique i have seen. Firstly, sticker like tiles i have, this is first time i have ever seen. Secondly i have question wont the weight which tiles have to bear crush the fiber optic and then dim it later on after few months of use ?

Wingloader (author)samalert2015-01-27

The adhesive to put down tiles is essentially cement. There would be zero movement in the tiles grout etc. If it did move (at all) you'd have a horrible floor and your grout would break loose. A properly installed tile floor should not move and is definitely not compressible.

Baldr (author)Wingloader2015-01-27

Wingloader is right, any movement in the tiles and the fibres are the least of your worries!

Dr The BoB (author)Baldr2015-01-28

Hi Baldr, I think samalert is asking about using the "peel and stick" tiles as opposed to the ones you need to grout in place.

samalert (author)Dr The BoB2015-01-29

Yes correct this is the first time i saw stickable tiles. I have seen grout one. The thing which creeped my mind is when two surface are to be sticked then one of the surface must be cushiony and when they are soft means movement, means fibre might be crushed.

Hope my point or thought going in my head is clear.

About This Instructable




Bio: Tinker: verb /ˈtɪŋ.kər/ us /-kɚ/ › to make ​small pointless ​changes to something to ​repair or ​improve it, knowing that one day, someone will break ... More »
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