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SEEDStack - Open 3D printable seed/sprout system

Food Hacker? Low on Kitchen estate? Small Budget? Mobile/Ghetto Kitchen? A nomadic Hacker in need of protein rich and vitamin packed food supplement with a very low weight/volume footprint in your backpack, which you can grow on-site? Afraid of the Zombie apocalypse and thinking about solutions for supply needs similar to the nomadic hacker's? Want to personally make a change and stop/reduce eating out-of-local-season import fruit, which would otherwise have to travel up to 12.000 km to get to you but worried about vitamin deficiencies? Try Sprouts.

Sprouts are generally considered as wonder foods. They rank as the freshest and most nutritious of all vegetables available to the human diet. By a process of natural transmutation, sprouted food acquires vastly improved digestibility and nutritional qualities when compared to non-sprouted embryo from which it derives. Sprouted foods have been part of the diet of many ancient races for thousands of years. Even to this day, the Chinese retain their fame for delicious Mung bean sprouts. Nom! Sprouts provide all the essential vitamins and minerals. They should form a vital component of our diet.

Seedstack Prototype

You basically just need seeds, water and a containment/growing environment that produces favorable conditions for the process. Nature does the rest. The SEEDStack is a Proposal/Demonstrator for such an open, integrated, modular and stackable containment/growing system. You can just grab the part files or adapt the model to print your own copies with a 3D printer. No heating or lighting is required, in fact, a dark environment produces better yields.

Goals:

  • Stackable, Modular & Parametric Design
  • Full Open-Source Hardware (OHL)
  • All parts printable, to mitigate local sourcing trouble
  • Optimized harvest performance
  • Make fully autonomous growing easy

Modules

After looking at many historic and current commercial implementations, the best elements and ideas were adapted, mashed up and broken down into several modules in order to have the most flexible setup and ease printing.

Lid

The Lid covers the topmost container in the stack so that each container is providing a closed section of moist atmosphere to create a favorable sprouting environment. The handle in the middle is actually the CERN OHL (Open Hardware License) Logo, with an added seedling growing from it. It's just a design element depicting how we can use modern open technology, to enable us to go back to basics, like growing food, by ourselves again.

Model

Slicing & Printing

Print Time Z resolution Filament Length/Volume
~3 hours 200 um PLA 15.5 m / 37.4 cm³

Container

These containers are the main pieces of the set. You can start with just one. When your circumstances require more harvest volume, you can simply print more of these containers and stack them on top of each other to a tower.

Model

This design approach reduces the necessary surface area for a seedstack and scales beautifully from just one to a whole set of containers, which can contain different seeds but all get flushed and fresh water automagically via the built-in auto-draining feature.

Key Features

  • Drain for automagic cleaning and flushing run
  • Bottom Spacing grid, keeping the seeds always 2mm above the actual bottom of the container
  • Integrated guides in all sidewalls to allow for flexible compartmentalization with one container
  • Case design to be stable enough for a tight fit but very lightweight and easy to print

Slicing & Printing

Print Time Z resolution Filament Length/Volume
~10.5 hours 200 um PLA 33.16m / 79.75cm³


Demonstrator

Checkout the following Video to see the delayed auto-drain in action. The container takes on a certain amount of water before actually starting to flush the water and then automatically drains itself completely, leaving only less than 1mm of waterlevel to keep the atmosphere moist and the seeds above on the spacing grid.


Siphon

The key feature of the auto-drain is the tube in the container and the following part which, once in place, turns the tube into a siphon. As long as the water level is not high enough to reach the end of the tube, it cannot escape the container. Once it has flown over, the falling water (gravity) creates suction in the siphon and continues to drain water from the container until the water level reaches the bottom of the inner tube of the siphon. Then it starts to pull air and the process terminates automatically. If you need different water/retain levels, you can simply change the height of the container- and siphon-tube respectively.

Model

OpenSCAD Code part

module syphon()
{
	difference()
	{
		union()
		{
			// Outer Skirt
			difference()
			{
				translate([0,0,syphon_skirt_height/2])cylinder(h=syphon_skirt_height, d1=syphon_skirt_outer_d, d2=syphon_tip_outer_d, center=true);
				union()
				{
					translate([0,0,syphon_skirt_height/2-0.1])cylinder(h=syphon_skirt_height+0.1, d1=syphon_skirt_outer_d-2, d2=syphon_tip_outer_d-1, center=true);
					for(x=[0:45:360])
					{
						rotate([0,0,x])translate([9,0,0])cube(size=[5,1,15],center=true);
					}
					translate([0,0,syphon_skirt_height/2+syphon_tip_height/2])cylinder(h=drain_h,d=syphon_tube_inner_d, center=true);
				}
			}

			// Inner Tube
			difference()
			{
				translate([0,0,syphon_skirt_height/2+syphon_tip_height/2])cylinder(h=syphon_skirt_height+syphon_tip_height,d=syphon_tube_outer_d, center=true);
				translate([0,0,syphon_skirt_height/2+syphon_tip_height/2-1])cylinder(h=drain_h+7,d=syphon_tube_inner_d, center=true);
			}

			// Tube Guides
			for(x=[0:120:360])
			{
				rotate([0,0,x])translate([4.5,0,drain_h])cylinder(h=drain_h+3,d=stg_d,center=true);
			}
		}

		// Bottom Cuts
		translate([0,0,-syphon_skirt_height/2+1.1])rotate([90,0,0])cylinder(h=syphon_skirt_height+syphon_tip_height,d=syphon_tube_inner_d, center=true);
		translate([0,0,-syphon_skirt_height/2+1.1])rotate([90,0,90])cylinder(h=syphon_skirt_height+syphon_tip_height,d=syphon_tube_inner_d, center=true);
	}

}

Slicing & Printing

Print Time Z resolution Filament Length/Volume
~18 Minutes 200 um PLA 0.35 m / 0.85 cm³


Bottom

In Progress…

First PoC Test-Run

Mung Seeds

Mung seeds have been selected as the first test candidate because they don't require to be cooked in order to become edible (some sprouts do), offer a great range of vitamins and minerals and should be easily obtainable everywhere.

Nutritional Value

A B1 B2 B3 B5 B6 B9 B12 C D E K Protein Minerals
X X X X X X X - X - X - 25% Fe, Ca, P,Mg, Mn, Na, Se, Cu

Procedure

The seeds have been completely submerged in room temperature tap water for about 8 hours in a cup, then put into the seedstack container. The seeds will sprout without this step, however, giving the seeds 8 hours in water seems to have an effect on the overall mass the sprouts will yield.

After putting the seeds into the seedstack container, they need to be flushed twice per day (morning/evening). To flush the seeds, about 500ml of water are poured in the topmost container (if you have more than one) and will drain automatically at the bottom of the container. This might also be a good job for an Arduino controlled valve/pump.

0h

First flush with the original (red) siphon.

+14h

The siphon was changed to the new printed (black) one and flushed again. Siphon operation test successfully concluded, almost all seeds have cracked their shell and begun to sprout already.

+38h

+62h

Development / Sources / Issue-Tracking

Anyone interested is of course also invited to download the model and play/use/verify/optimize as well. Feedback, PR's and everything else that might improve usability, features and safety are welcome:

https://github.com/apollo-ng/seedstack

Roadmap

  • Create water collecting bottom part - In Progress
  • Create simple compartment dividers for container
  • Create pressure sieve to put onto sprouts to add artificial weight

FAQ

Can/should you put/grow food in something you made with a 3D Printer?

Without further open, transparent and long-term study, it's hard to come up with a more definitive answer but when we look at industrial food containers and some of the more recent issues about migration of plastic components or additives - mostly phthalates (PAEs), alkylphenols (APs), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A or BPA) and di(2-ethylhexyl)adipate (DEHA) - we have a couple of available 3D printing material choices:

  • PET
    • Already widely tested and deployed in industrial packaging applications
    • Probably best choice of material at this point

In both cases, a full stainless-steel hot-end is also recommended, to eliminate potential lead traces introduced by a brass nozzle and to make it a habit to have a conscious disinfection/cleaning/drying step in your post-harvest workflow to reduce bacteria build up before put into storage until used again.

Why not just use $ware Containers?

  • They don't stack
  • All other non-seed/sprout specific container lack a delayed draining feature and the design to let the seeds float above the water. The containers need to be flushed at least twice a day (more tests will determine what seems to be the best practice for specific seeds) while at the same time providing a floating phase for the seeds where they're completely submerged in the fresh water. For the rest of the time the seeds should not be in contact with too much water since that will lead to a bad harvest, fungi problems and rot.
  • They're proprietary and IP encumbered things we simply don't want to have and use anymore.
  • They're a generalized product where you as the customer have to live with its design limitations and have no real way of giving feedback to the manufacturer to make a size specifically for your needs (up to 100 micrometer) or change something about the design you'd like to have modified. Our current industrial implementation simply cannot cope with this form of freedom and versatility to build something exactly according to our needs. Instead, we have to cope with the products industry provides while it should actually be the other way around.

DIY 3D printing is already beginning to leverage this situation. Today we can just share parametric projects and change a couple of numbers in a file for basic changes or have the freedom to copy, remix, adapt and extend everything as we like and share that with the rest again on github.com or platforms like http://www.thingiverse.com.

As all emerging revolutionary technologies before, like the Internet or mobile communication, 3D printing is still in its Kindergartenphase, where we have to play and learn what this technology will enable us to do in the long run, like the early days on the net, when we never had a clue how big the Internet would grow and how far it would exceed our wildest dreams of connecting and sharing our ideas and solutions with everyone in real-time.

In the early days we still used the Internet as a mere extension for our ego where we could show what we have done and how cool that makes us to a broad audience. With better cams and more and more people changing their MO away from themselves and towards HOW we are doing things, so that others could benefit from the confidence that it obviously can be done as well as free information how exactly it was done so that others may just copy and build upon it. Videos made the transfer even easier.

Now we start being able to produce the things we need on a very individual level with almost no considerable bootstrapping time. If we can go to Amazon and have them build anything exactly to our requirements and deliver within 24 hours for a fair price: Awesome. Until then: On-Site 3D Printing FTW. The 3D printer market is expected to grow from 100,000 units in 2014 to about six million units in 2018, Digitimes reported referring to the Industrial Economics & Knowledge Center (IEK) under Taiwan's Industrial Technology Research Institute.

We have basically achieved what probably has inspired most Star-Trek fans too: A system (the computer) we can ask any question and get a broad scope of possible answers to make up our own mind about it (Internet) and now: Replicators. They might not work even close to real-time yet, but who cares? Never forget: It's not your time. You can do something else in the time it takes a 3D printer to produce the thing you've tasked it to print.

Does sprouting increase the nutritional value?

Journal of Food Science (1975), 40(5), 1008-9 CODEN: JFDSAZ; ISSN: 0022-1147. English. Dry seeds and sprouts of Alfalfa, Lentils, Mung and Soy Beans were analyzed for selected nutrients. Sprouts compared on a solids basis contained Ca [7440-70-2], Fe [7439-89-6], and Zn [7440-66-6] at levels about the same as the seeds while protein was higher and fat content lower in sprouts. Total vitamin C [50-81-7], thiamine [59-43-8], niacin [59-67-6] and riboflavin [83-88-5] content was higher in sprouts than seeds, vitamin C showing the greatest increase. Cooking slightly lowered heat-labile nutrients. Galactose-containing sugars of Mung beans disappeared upon sprouting. Based upon chem. analyses, nutrient levels of sprouts compare favorably with other fresh vegetables.

Discussion

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