Models Showcase: free 3D-printable organizers

By Krypto

Complexity

Multi-part assembly

Others Sustainable living

0

MAIN PURPOSE: Grow a solid brick of mushroom mycelium as a biodegradable building material

Mycelium, the root network of mushrooms, can be grown into solid shapes and is already used for packaging and insulation. Pack this mould with pasteurised sawdust or hemp mixed with oyster mushroom spawn, put the lid on and leave it somewhere dark. In about a week the white mycelium has bound everything into a light, solid brick. Pop it out, bake it at 90 degrees for an hour to stop the growth, and you have a block that is fire-resistant, insulating and fully compostable. The small vents let it breathe.

Printing notes

382.3 cm³

Volume

474.1 g

Est. weight

36,208

Triangles

PETG; wipe with alcohol first. Use oyster mushroom grain spawn mixed with pasteurised hemp hurds or sawdust. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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Preview of Cricket-chirp thermometer cage

By Krypto

Complexity

Multi-part assembly

Others Pets & aquarium

0

Cricket-chirp thermometer cage

MAIN PURPOSE: Keep a singing cricket and read the temperature from how fast it chirps

Crickets chirp faster when it is warm, so regularly that in 1897 the physicist Amos Dolbear turned it into a formula: count the chirps in 14 seconds and add 40 to get the temperature in Fahrenheit. (For Celsius, count chirps in 25 seconds, divide by 3 and add 4.) This ventilated cage keeps a cricket comfortable with slotted sides for air and sound, and the formula is raised on the front so the living thermometer can be read without a phone.

Printing notes

316.3 cm³

Volume

392.2 g

Est. weight

44,456

Triangles

Give the cricket a slice of carrot and an egg-box shelter; a pet-shop house cricket works. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Science & education

0

Raindrop-size flour tray

MAIN PURPOSE: Measure the size of raindrops by catching them in flour

In 1898, the snowflake photographer Wilson Bentley measured raindrops by catching them in flour: each drop rolls itself into a little dough pellet the same size as the drop. Take the lid off in the rain for a few seconds, cover it again, and let the pellets dry for an hour. Sift them out and drop each through the gauge holes beside the tray, from 2 to 7 mm. Drizzle makes tiny pellets, a summer storm makes big ones, and you can compare showers through the year.

Printing notes

141.2 cm³

Volume

175.1 g

Est. weight

7,740

Triangles

Fill with sifted plain flour 1 cm deep. Expose it to the rain for 2-3 seconds only, then put the lid back on. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Kids & play

0

Scytale cipher tube

MAIN PURPOSE: Send secret messages that only a tube of exactly the same width can read

The Spartans sent secret orders 2,500 years ago with a scytale. Wind a narrow strip of paper in a spiral round the tube, write your message along it, one letter per turn, then unwind it: the letters scatter into nonsense. Only someone with a tube of exactly the same width can wind it back up and read it. The flat faces of this hexagonal tube keep the lines of writing straight, and the strip lives inside it under the screw cap. Change the width before you print and your pair of tubes becomes your own unbreakable key.

Printing notes

96.4 cm³

Volume

119.6 g

Est. weight

2,844

Triangles

Print two identical tubes, one for each friend. The diameter is the key: change the width to make your own private cipher. Prints as shown on its floor, no supports. The threaded lid and its neck piece print separately; adjust Fit in the Lid tab if it binds.

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By Krypto

Complexity

Multi-part assembly

Others Kids & play

0

Vanishing-coin magic box

MAIN PURPOSE: Drop a coin in, shake, open the lid, and it has gone

A magician's prop with a secret in the floor. Show the empty box, drop in a coin, close the lid and give it a shake so everyone hears it rattle. Then, holding it from underneath, tilt it slightly towards you: the coin slides through a hidden slot along the floor edge straight into your palm. Shake again (silence), lift the lid, and the box is empty. Produce the coin from a spectator's ear for the finish.

Printing notes

43.0 cm³

Volume

53.3 g

Est. weight

12,648

Triangles

Print in a dark colour so the slot under the floor edge is invisible. Practise the tilt in front of a mirror. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Garden & plants

0

Cube-fruit growing box

MAIN PURPOSE: Grow square cucumbers, courgettes or mini melons inside a clear box

Japanese farmers first grew square watermelons in the 1970s so they would stack in shops and fit in fridges. This clear box does the same for smaller crops. Slip a young cucumber, courgette, mini melon or even an apple into it while it is still small, rest the stem in the notch and put the lid on. As it grows it fills the box and takes its shape, coming out a near-perfect cube with sharp corners. The drain holes stop rain pooling inside.

Printing notes

68.9 cm³

Volume

85.4 g

Est. weight

840

Triangles

Print in clear PETG. Put the young fruit in while it is half grown, stem through the notch, lid on; pick it when it fills the corners. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Garden & plants

0

In-bed worm tower

MAIN PURPOSE: Compost kitchen scraps right inside a raised bed through a worm tower

Instead of carrying compost to the plants, bring the compost to the plants. Bury the lower half of this tower in a raised bed, drop in some compost worms and feed it vegetable scraps through the lid. Worms come and go through the windows near the bottom, eating the scraps inside and leaving their rich castings out in the bed around the roots. The lid keeps flies and smells in, and one tower feeds roughly a metre of bed.

Printing notes

228.0 cm³

Volume

282.8 g

Est. weight

7,188

Triangles

It is 240 mm tall, so lower the height on a smaller printer. Bury the bottom half in the bed so the side windows are under the soil, add a handful of compost worms, and feed scraps through the lid. Prints as shown on its floor, no supports. Large holes in the walls may need supports or good bridging. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Tabletop gaming & play

0

Monty Hall three-door game

MAIN PURPOSE: Play the famous probability puzzle with three lidded boxes, one prize and two duds

You pick one of three doors. The host, who knows where the prize is, opens another door to show a goat, and asks: do you want to switch? Most people say it makes no difference. It does: switching wins two times out of three. Even mathematicians argued about it when it was published in 1990. Hide a prize in one of these three numbered boxes and test it at the table: play twenty rounds each way and the tally does not lie.

Printing notes

164.4 cm³

Volume

203.9 g

Est. weight

11,920

Triangles

Hide a sweet (the car) in one box and nothing (the goats) in the other two. Play 20 rounds sticking and 20 switching, and keep score. Prints as shown on its floor, no supports. The lid prints as a separate part, top down. The added bases' lids print separately.

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By Krypto

Complexity

Multi-part assembly

Others Photography & film

0

Solargraph sun-trail camera

MAIN PURPOSE: Record six months of the sun's path on one sheet of photo paper

A camera with a six-month exposure. In a dark room, curl a sheet of ordinary photographic paper round the inside of the back wall, close the lid and tape it. Strap the box to a post or railing facing the sun (south in the northern hemisphere) and leave it from one solstice to the next. When you open it, do not develop the paper: scan it. Every sunny day has burned its own arc across the sky, with the gaps showing the cloudy days, over a ghostly image of the view.

Printing notes

39.3 cm³

Volume

48.7 g

Est. weight

9,196

Triangles

Print in black PLA. Tape a square of kitchen foil with a needle hole over the 6 mm hole, and tape the lid shut. Prints as shown on its floor, no supports. The lid prints as a separate part, top down.

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By Krypto

Complexity

Multi-part assembly

Others Kids & play

0

Pepper's-ghost haunted box

MAIN PURPOSE: Make a ghost appear and vanish inside a box using a hidden sheet of acrylic

A Victorian stage trick in a box. Look through the window and you see a dark little room. Switch on the tealight in the hidden side chamber and a ghost (any small figure or a cut-out picture you put beside the light) appears floating in the middle of the room, then fades away when you switch it off. A clear sheet standing diagonally across the box reflects the lit side chamber over the room behind it: the same trick, called Pepper's ghost, that makes holograms on stage and ghosts in theme parks.

Printing notes

416.0 cm³

Volume

515.9 g

Est. weight

10,800

Triangles

Stand a 220 x 110 mm sheet of 2-3 mm clear acrylic (or photo-frame glass) diagonally from the front-left to the back-right corner. Use a battery tealight. Prints as shown on its floor, no supports. Large holes in the walls may need supports or good bridging. The lid prints as a separate part, top down. The added base's lid prints separately.

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