Introduction: Black Hole Table
This table evokes the warping effect on space and time exerted by a black hole. The table consists of black acrylic rings intersecting with a radial array of ribs that plunge downwards into a central hole, and an infinity mirror at the bottom gives the impression of an event horizon as the warping descends through the floor. A circular tempered glass top provides the functional table surface.
Second photo from BBC article "These are the discoveries that made Stephen Hawking famous" (Henning Dalhoff/Science Photo Library)
Third photo from NASA article "Black holes: Monsters in Space" (NASA/JPL-Caltech)
Step 1: Design
I used Fusion360 to draw a spline curve that matched the 1/r warping that occurs near massive objects in space, then incorporated a cutout for the infinity mirror, a base that splayed out for support, a profile that would be strong enough to hold the glass top, and a flat surface so it would be held securely. I used the Create > Revolve tool to generate a 3D shape. I saved that shape as an STL file then opened it in 123D Make. I used the "Radial Slices" construction technique to generate a frame that could be easily fabricated using a laser cutter. I custom designed the material as 1/4" acrylic, and went for 7 horizontal layers and 15 vertical ribs, because I felt that looked pleasing and would be structurally sturdy enough, and exported the print files.
Step 2: Laser Cutting
I managed to fit all 22 pieces on to 5 sheets of 2'×2' 1/4" black acrylic ($155) by manually nesting them in Illustrator. The files are attached. Laser cutting was done on a 120 W Epilog laser. I peeled the sticky paper off and stacked all pieces ready for assembly.
Step 3: Assembly
I used a jig to get the first rib in place, then got help for the rest (thanks Mei!). With two people, it was pretty straightforward to assemble. The acrylic varied in thickness somewhat, so some pieces went in easier than others.
Step 4: Infinity Mirror
I 3D printed an enclosure for 30 LEDs which I also designed using Fusion360 (STL attached), and added a 6" mirror to the bottom. 60% of an addressable RGB LED string was inserted in the holes (just cut the string between the 30th and 31st LEDs). Note the design accommodates the features on the LED casing, so rotate them to align correctly and seat them all the way in. Tuck the wires neatly into the bottom of the enclosure, under the shell of each LED. A 6 1/4" piece of one-way acrylic mirror (1/8" thick, cut on a laser cutter) was added to the top. It was powered with a 5 V supply and the LEDs controlled using an Arduino Uno (Teensy version with a single power supply coming soon). The LEDs are set to a pulsing purplepattern, invoking the idea of a high energy pulsar (which is actually a neutron star, not a black hole, I know).
The STL file for the enclosure and the Arduino sketch for the pulsing purple light are attached.
I published an instructable separately on a larger warping infinity mirror, also featuring an LED string and a 3D printed enclosure.
Step 5: Glass Top
I ordered a 32" circle of tempered 1/4" edge-polished glass for the top online ($90).
Step 6: Put It All Together!
Place the table over the infinity mirror and put the glass top on. Set it up in your living room and enjoy the geekiest coffee resting platform ever!
Planning to make one of these? As you won't need to make all the mistakes and iterations I made along the way, it ought to be pretty straightforward. A one-year instructables.com premium membership to anyone who posts a photo of a table inspired by these plans.
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