Instructables user Baldr decided to add a geeky element to his bathroom. Using fibre optic cables laid under floor tiles, he managed to create a constellation under his feet. He used PMMA plastic, which looks like fishing line, but if you shine a light in one end, it travels to the other side. He said the project took two weeks, but the end result was well worth it.

via Baldr Instructables – h/t Bored Panda

Bundling Fibres
Baldr explains the first thing you need to do is decide how many fibres you want per square metre of floor and where you wish to situation your light source.It’s advised to place your light source outside of the bathroom for safety reasons, making the whole bathroom installation safe. Then create your bundle of fibres, making certain that each strand is longer than the furthest point you want it to reach. Use a cable tie or sparky tape to secure your bundle at the end where you will attach the light source. Contrary to normal tiling procedure where you begin from the centre line and work outwards, for this project, you will want to begin tiling from your light source. The reason for this is when you float the adhesive onto the floor you will be scraping the floor and it must be clear of fibres. Begin laying the tiles, keeping the fibres spread out as you go. It’s imperative to keep the fibres spread out especially on the first tile, because it is closest to the light source and will have the most fibres underneath it, it will not have very much floor to stick to.

Peel, Adhesive, Fibres, Tile
Once the first tile is down, lift all the fibres up out of the way, and adhesive the floor for the next tile. Baldr suggests asking a friend for help with this part. It’s easier to spread the adhesive one tile at a time because of how fidgety the fibres are. Wherever you want a star to appear, pull up the fibre in between the tiles. Try to make sure the fibre is perpendicular to the tile edge and sticks up as vertically as possible

Fibres Pulled Out
Repeat the above process until your floor looks like this.

Time To Grout
Baldr’s first piece of advice here is do not grout like a pro. Because the fibre optic strands are fragile, normal grouting procedure will cause them to break. Use a good flat float, and carefully work the grout in. The fibres will move, so be gentle. He encourages you to trim the fibres before you begin grouting. He suggests leaving 10cm sticking through the tiles. Grout the sections that have no fibres as you would grout normally. When you come to a fibre, use the float and your fingers to gently grout around it. Don’t worry about small holes. So long as the grout holds the fibre in place, leave it. You can always grout around each fibre to fill holes once you have finished a first layer. Once the grouting is complete, using a hot knife, trim the fibre as close to the grout as possible. Then grout a third time to ensure all holes in the grout are filled.

Almost Done!
Now it’s time to light your strands. Baldr used a 3W Cree LED torch focused down to a narrow beam with a PSU tacked in to replace the batteries. There are no colour or twinkling effects however. Baldr advises that you can order a light source kit, however they can be pricey. And voilà, you’ve got yourself a starry floor!

The Final Result

Close Up

Check out Baldr’s Instructables for more info and other cool projects.