Discworld Table

THEY SAY THE world is flat and supported on the back of four elephants who themselves stand on the back of a giant turtle.

They say that the elephants, being such huge beasts, have bones of rock and iron, and nerves of gold for better conductivity over long distances.

They say that the fifth elephant came screaming and trumpeting through the atmosphere of the young world all those years ago and landed hard enough to split continents and raise mountains.

No one actually saw it land, which raised the interesting philosophical question: when millions of tons of angry elephant come spinning through the sky, and there is no one to hear it, does it – philosophically speaking – make a noise?

And if there was no one to see it hit, did it actually hit?

— The Fifth Elephant - Terry Pratchett

A few years back, my family and I were remodelling our old center table and, as we are all fans of Terry Pratchett’s Discworld, we decided to base it off of the Discworld itself (A Disc shaped flat world, sitting on the back of 4 elephants, that are being carried by a giant Space turtle, named the Great A’tuin).

The table is designed as a square 30”X30” with a central column 18.5”X18.5”X12” on a base of 30”x30” square. It has the Great A’tuin’s head and fins sticking out of the central column’s corners stuck with a galaxy resin pour that reaches the edges of the table giving the feel of it floating above space; 4 elephant heads centred in patterned walls with holes in them to allow diffused light from LED strips in the back to light the elephants; and the laser cut, labelled Discworld sitting under a mirrored glass pane to make an infinity mirror effect to represent the magical waterfall that falls off the Discworld.

Tools:

1. A 3D printer
2. A laser cutter
3. Soldering Iron / Crimping Tools

Materials

1. 12V Warm White LED Strips (60 LEDs/m) – 5m
2. 5V Addressable RGB strips (60 LEDs/m) - 1.5m
3. ESP32 Development Board and associated electronics (see Electronics step below)
4. Black paint
5. Silver Paint
6. Black PLA filament
7. Dark grey PLA filament
8. Resin and Mica based Resin Powders
9. Mirror
10. 5mm Glass
11. A 2-way mirrored film

Software Used

1. Autodesk TinkerCAD
2. Onshape
3. Luban3D
4. Inkscape
5. Superslicer
6. PlatformIO

The basic table shape was created using ¾” MDF with the dimensions in the attached images

The MDF boards were cut at the shop and joined using wood glue and screws.

DO NOT join the top portion right now, as you will need to install the electronics and other parts before installing the top. Drill a hole in the center of the top portion for wires to come up.

For the disc and the jali background behind the elephants, 6mm MDF was cut using a laser cutter.

The disworld map was traced and edited from the scanned images by reddit user Tooko1005 [https://www.reddit.com/r/discworld/comments/pofwmn/super_high_resolution_discworld_mapp_for_your/] using InkScape

The attached SVG files have the patterns. Black is for cutting out, Red is a 0.15mm engraving, and Blue is a 0.1mm engraving. The first 2 sheets can simply be cut, but the disc is far more complex, requiring both cutting and glueing the continents onto their pre-engraved places.

The Jali consists of 4 panels lasercut in MDF (please note, the 4 panels have slightly different patterns so that they can mesh together, so DO NOT cut one pattern 4 times). The pattern was cut using Luban3D software

The next step would be to 3D print the elephant heads and the Great A’tuin’s fins and head. The elephants are best printed in a light or dark grey colour, but if you don’t have the filament in that colour, you can paint it instead. The same applies for the Great A’tuin. You also may want to use a high infill density for the elephant heads as we have found out the hard way that the tusks and trunks are very fragile and easily snap off while cleaning them. You can find the STLs below, although I would recommend using tree supports for the elephants as they snap of easily and any residue is easily hidden.

Both STLs are modified versions of the free models from these two linked sites:

1. http://3dmag.org/en/market/download/item/6853/
2. https://3dmag.org/en/market/download/item/2786/

The STLs were split using Luban3D and TinkerCAD as they are very easy to use

First, paint the entire table black. If you want to add a fun detail you can draw something on the inner square on the base of the upper part of the table that is covered by the inner column, for example I personally drew a Smiley face on the bottom when we were doing this, and it is a fun detail that nobody would know about unless you show them the photos or it in person.

Then, paint the outer side of each frame that holds up the elephants a light silver. Although the bottom part (the bottom till the cutout shapes design) should be coloured black.

After that, you may optionally paint the map after gluing all the continents to it or use light blue resin to cover all the oceans and waterbodies. We personally chose the resin option, but it also covers up the engraved labels that are the names of the location. You may also choose to not do anything which also looks fine; however, it is not as good as the other options.

Also paint the elephants and Great A’tuin if you did not print them in the preferred colours.

Creating the Base

1. Wrap 12V warm white LEDs around the central column with the wires running inside.
2. Connect all jali pieces together around the central column, using the pre-existing guides that allow it to lock together without glue, although I do recommend adding glue as well for long term stability.
3. Position all the fins and the head of the Great A’tuin, aligning the head with one of the corners, positioning the frontal fins near the centres of the 2 adjacent sides to the head, with the other 2 fins being positioned near the back of the other 2 sides (with the head as the front) and glue them to the base
4. Attach the elephants STLs to the jalis with more glue. Slide a plastic diffuser behind the Jali.

Resin Pour for the Base

1. Surround the table base with a removable border (plastic sheet, thick cello tape, etc.) to provide a mold for the resin.
2. Do a galaxy pour with resin colours of your choice (I would recommend some gold and green with hints of blue with mainly clear or black resin).
3. This both attaches the head and fins while also adding an effect of the Great A’tuin floating in space.

1. Glue the lasercut continent portions on the main disc
2. Raise the disc 12mm to ensure there’s space for electronics under the disc.
3. (Optional) – paint / pour resin in the oceans
4. Glue 5V Addressable LEDs around the perimeter of the disc – this would form the magical waterfall (Rimfall)

Hardware

1. ESP32 Development board
2. 1.5m 5V Addressable LEDs (WS2812B)
3. 12V to 5V 3A Power Module DC-DC
4. Sparkfun Level Shifter
5. SN74AHCT125N Level Shifter
6. 2x IRFZ44N Mosfets
7. Wires
8. 12V 5A Power Supply

The circuit

Connect the following:

1. +12V to
2. VIN of ESP32
3. VIN of 12V-5V Power Module (DC-DC)
4. HV of Sparkfun Level Shifter
5. +12V of Warm White LED Strips
6. PIN 2 of ESP32 to LV2 of Level Shifter
7. PIN 4 of ESP32 to LV1 of Level Shifter
8. 3V3 of ESP32 to LV of Level Shifter
9. PIN 5 of ESP32 to 1A of SN74AHCT125N
10. PIN 1OE of SN74AHCT125N to GND
11. 5V of SN74AHCT125N to 5V Module
12. 1Y of SN74AHCT125N to Data In of WS2812B LED Strip
13. +5 and GND from Power Module to WS2812B LED Strips
14. GND of Warm White LED Strips to IRFZ44N MOSFETS (One each)
15. HV1 of Level Shifter to Gate of IRFZ44N 1
16. HV2 of Level Shifter to Gate of IRFZ44N 2
17. Connect all GND together

Programming the ESP32

The code for the ESP32 is present on GitHub:

https://github.com/dushyantahuja/ESP32-Discworld-Table

There are multiple tutorials for programming the ESP32 using PlatformIO – please refer to them, as I’m no expert.

1. Glue 12V Warm White LEDs under the top portion (this would highlight the elephants and the turtle).
2. Screw and Glue the Top, snaking the power and LED wires through the hole.
3. Snake cables through the hole in the mirror and place mirror on the top
4. Connect cables to the ESP32 Electronics
5. Place the Discworld in the center
6. Prepare the glass sheet with 2-way mirror sheet. Cut a 17.5” dia circle in the center of the 2-way mirror sheet (be careful with measurements here – we ended up with the cutout off-center). Place the glass sheet on the Top
7. Place the painted top cover ( ¼” MDF) to enclose the glass and electronics in a safe way

The mirror and 2-way mirror sheet create an infinity effect. Infinity mirrors use two-way mirrored film to create an effect of it infinitely extending endlessly inward, making it feel as if it is much deeper than it is.

This was a great experience for making this years ago and it taught me many things about building projects and using electronics. We also learned from our mistakes, and made changes to the table over the years:

1. We were previously using an ESP8266 with an Arduino together to control the LEDs and we recently switched to an ESP32. This provides a simpler circuit and stable wifi control.
2. We didn't use level shifters for controlling the Addressable LEDs and this led to them glitching.
3. To save filament we, printed the elephants using very low infill and perimeter counts.
4. Used handmade paper to diffuse the lights, this got dirty over the years with no way to clean it. We’ve replaced it with a textured plastic sheet that can be wiped easily.
5. We also accidentally mis-measured the cutout of the film and that led to us having the disc off-centre.
6. We poured resin over the disc’s waterbodies to make it more aesthetically pleasing, however this hid the engraved markings on the oceans
7. The original design had the base on the floor, and the top was very close to the elephants - so that the elephants were not fully visible. A simple solution was to print spacer pieces that increased the height by ˜1" (see attached STL).