Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Rotary Hydroponic Unit

by 4ndy, published

Rotary Hydroponic Unit by 4ndy May 20, 2011

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24351Views 21780Downloads Found in Biology


Who said we couldn't print useful things? Here's a flat-pack modular rotary hydroponic unit to be produced by most CNC tools.

My Blog Post about this here: http://engineeringourfreedom.blogspot.com/2011/05/do-cartwheels-feed-people.html

For working examples of such a system, see OmegaGarden.com RotoGro.com or H2ODynamic.com

Call it the ModRotoHydro, RapFarm, FeederBot, [email protected], or whatever else you like, I don't care, just help me build them and feed the world. ;D

Some bits of the assembly are made from or based on standard mendel parts, such as the frame vertex and Prusa's Y-bar clamps. The current gear-tooth profile is based on http://www.thingiverse.com/thing:8077; I might try a version with an easier-to-print zigzag, though it may be less efficient.

The cylinder has an outer diameter of 1 metre, ID of 80cm, and the trays are designed to hold 75mm/3" rockwool cubes, though it would be very easy to design alternate holders for smaller sizes.

Currently I have designed the system to use a gear ratio of 11/1056, i.e. 44 teeth on each of 24 segments, using a 3-3.6rpm synchronous motor pulled from the base of a broken halogen heater. If you want me to release alternative parts, e.g. with different numbers of teeth on the segment, just say so and I'll get on it for you.

I have been designing the base-frame to try and use 1m lengths of studding with as little random waste as possible, but you could construct this at different sizes with odds and ends if you so wish. It doesn't make a difference so long as a tray and reservoir can fit under the cylinder.

The tray support designed is now up. It uses 8mm studding to span the gap in the design, but I think you could possibly use some 6mm dowel, but don't take my word for it until you or I have done a stress calculation. I'm thinking of having it so you simply hang a polyethylene sheet across the gap in the base to make a sump for the nutrients. There needs to be a hole in the bottom to drain excess away into a reservoir though, and some kind of hose line up from the reservoir to pump it in.

The weight-saving gaps have mostly been placed conservatively using intuition and best practice of avoiding sharp corners, but I have yet to do any FEA on the components to see if this can be improved for even more strength and less weight. However, I expect design 1.0 to work as it is with lightweight infill settings.

Any DXF files that end with a measurement are giving the reccomended thickness of sheet to cut the part out of, in order to fit within this design, however you may be able to change these around a bit and file holes down to fit.

Let me know if you want another file format. I added a DXF of the geared segment face on request, for anyone able to cut that profile halfway through a 10mm board. I promise I'll get round to drawing up a less-botched-together motor mounting part that follows some kind of one-size-fits-all geometric rule (eventually).


Use the supplied eDrawings executable assembly file to take relevant measurements.

  • Acquire studding, nuts, bolts, washers, bearings, plastic or mdf, lights, a low-speed motor, some grow medium and hydroponic fertiliser. (Optional: water pump and timer) (Alternative - build the base out of MDF or any scrap wood/fibreboard pulled from a skip, with a few holes to mount rollers/bearings on)

  • Print or laser-cut all the flat structural parts.

  • Cut and file studding to size.

  • Build a base appropriate to the number of rings you want in a cylinder.

  • Fit your lights, motor and feeding tray.

  • Build as many rings as you can fit on the base.

  • Test that the motor turns the cylinder through one full rotation in about 30-40 minutes.

  • Soak rockwool cubes and balance the pH of the surrounding solution to about 6.

  • Germinate seeds or propagate cuttings in 1-inch rockwool cubes.

  • Plug the starter cubes with well-rooted seedlings into holes in the 3" cubes.

  • Quickly load the cubes into the trays on an assembled ring, and secure them with the grow-medium retainer pins.

  • Rest your planted ring on the base (Optional: adjust the base width if you already have one or more on there, and bolt them together)

  • Hit the lights and start the motor.

  • Set your timer to pump nutrient solution into the sump for 1 hour a day, every day, or DIY with a jug.

  • Eat tasty fresh food! ^_^ (Especially things out of season that would be wasteful to import)

*...Oh wait, there's a step in there somewhere about replacing old media, but who cares... :P

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WELL DONE! I have been looking for a design that I can work with at home, that is scalable... THANK YOU!

Yesss! I wanted to design this thing for a while now, so awesome to see that it is already been done!

Update of something interesting that I found a few months back and forgot to mention... here's an interesting study showing that regular old sheep's wool can be used as a very effective hydroponics medium: http://www.actahort.org/books/779/779_36.htmhttp://www.actahort.org/books/... (they were growing cucumbers in the study in question).

So maybe I don't need to worry anymore about rockwool having a very energy-intense production process, and hence being a nasty expense. Where I live, people herd loads of sheep, so I can literally pick up clumps of dropped wool in nearby fields or on fences.

do you have photos or videos of the whole thing printed and working ???

Sadly no, I haven't been able to afford the plastic to print one yet, since filament prices are so extortionate here. However, I'll try to build a decent waste plastic grinder soon, and then I may either sand-cast negatives to injection-mould parts in (this could work really well as there are so many repeated parts), or build a 3mm filament extruder, to bring the monetary cost way down.

Hi, I'm trying to cut this out with a laser cutter, but i don't see the DXF version of the geared ring segment.  Do you have one?  Thanks

That's awesome to hear, since I've only just got in contact with an old friend who could help me to prototype this here.

I'll get a DXF of that up just now. I thought it could be awkward to laser-cut that part on account of the gearing being cut to half-depth and the remaining half of the outside edge being used to roll on, I guessed some other arrangement like cutting a notch out and gluing a toothed belt in that place could be neater, but if you have some experience with a laser cutter you might manage to cut this out in one go.

Another way to work this could be to cut out individual small curved 'rack & pinion' style rows of teeth and bolt them on the sides of each segment further radially-inwards, with a different motor mounting. Otherwise you could try replacing one idle bearing/pulley with a driving wheel turned by a motor, in order to turn the larger wheel by friction - this is what I've seen some commercial systems do.

Sorry for the misspellings on my previous comments.

Just some thought.

Weight - Looks as if the full assemble unit would have a tare wieght of about 15 - 18 lbs. When loaded and wattered (singl load - all sections loaded woul add another 8-10 lbs loaded (Water retained, plant medium
amp; full grown plant) . My concern is the narrowness and composition for the make up of the gears and ring teeth. Most systems this size woul use a metal gearing system tied to a chain drive that ould drive a set of rollers on a single axis that is driving both sides of the wheel . This would definitely eliminate the wear on the rings segment and facilitate easier maintenence on the drive unit. (if 1 segment of the geared ring faile, you have to reproduce a new segment and put it in place. thereby possibly causing imbalance of the ring assembly. Just a thought.

Instead of producing a plant holder, perhaps it would be better to develop a "holding" device so that standard size 3" or 4" planting cones/cups could be used. This would greatly reduce production time and increase avability of plant medium/containers that are avaiableat and lawn and garden cent
er. Also would shorten harvest and reduce requirement for some disassembly the unit to get to plant holders.

In addition to that my question is that can you utilize every segment of the wheel to hold the lants. From forst look, it appears you can. This will increase capacity of growing product

In addition, one should make this material thath is dark grey or black, as white has a tendency to be effected by UV rays and suseptible to algae/moss growth.

I remember seeing this thing last summer. Great idea. Now we are making our own version of a printable rotating garden. You can't print the Kontinuum Garden on a regular sized reprap but that is why we are designing a large printer too. Check it out and tell us what you think.

I like your idea of an alternate production scale in between my mini-replaceable-parts set and the one-sweep moulding that omega garden use for their volksgarden.

We'll just have to see how robust and easy-to-build that 1x1m printer can be, and what print times are like. The last attempt I saw at something like that was http://reprap.org/wiki/MegaMendelhttp://reprap.org/wiki/MegaMen..., which is barely half the size of what you want.

Though thankfully now we know it can be done, what with the Kamermaker
coming out since then :P http://www.youtube.com/watch?v=o7qut2GepEUhttp://www.youtube.com/watch?v...

This is one of the few things on thingiverse that really makes my jaw drop, great idea!

based on my math and limited knowledge of light measuring, I believe you would need 1660 LEDs (assuming 1.2 lumens a piece, which seems to be standard for Red surface mount) per square foot of growing space 1 foot from the light source to reach 2000 lumens, which I believe is the on the high end of growing things. If you could find say 10 lumen or higher LEDs it might be more reasonable.

I've been pricing around, and unless you happen to find a bulk or surplus deal it seems like it would cost about $200-500 per square foot of lit area =(

with these you could get it down to $80 a square foot... http://www.lc-led.com/View/itemNumber/486http://www.lc-led.com/View/ite... ..and it would be still be 80 watts per square foot =(

I don't know jack about lighting or physics, but these might be closer to what you're looking for




Keep in mind you'll need to heatsink those suckers with something.

Very nice, but damn expensive.

Just out of curiosity, what have you printed this with and how long did it take? Could I leave it queued on a thing-o-matic, how long would it take?

I have access to a 4x4 plasma cutter, but it only has about 1/16 to 1/32 accuracy so it couldn't do the smaller pieces, but i'm wondering if I could big rings of stainless or aluminum and then print pieces to between them? I wouldn't be able to cut the gears, so I would have to go belt driven...

Or I wonder about cutting it out of sheet abs or acrylic on a laser cuter? There would still be pieces to print, but I trying to think of ways to speed up production, I'm thinking of building enough to go around a 2,3 or even 4 foot bulb...

I haven't printed any bits of this design yet, though I intend to try it in ABS once I get some fume filtration going. As it says above, the design is in progress at the moment, and I ought to put some measurements in detailed instructions.

You could probably do this in aluminium with those tools, though you might want to be wary of the weight of metal parts and make sure you find a good motor to turn it.
As far as I have seen, the cheaper commercial solutions have so far been turning cylinders just with the friction against rollers,
except maybe the rotogro ones now that I look at it.

With a smooth ring you might be able to get away with gluing some cut belts around the outside then running a gear up against it :)
If anyone has ideas for a cheap drip tray, I'd like to hear them. At the moment I'm just thinking of hanging bars
across the base and stretching a thick poly sheet over them, but there might be better ways of doing it.

I think your right about the weight of aluminum, if I do that, I think I would increase the width to justify the use of aluminum for structural parts ;)

Any chance of getting the main file with all the parts assembled?

As for the drip tray, if you moved base supports further apart you could probably fit a standard drip tray from home depot or your nearest gardening store. If it was abs you could print your own in/out hose nipples and acetone the
m to the tray?

Great work with this =) you've totally inspired me, I have one more semester and then a year long senior thesis project at my college, and i'm totally tempted to do something on urban farming and rotary hydroponics =D

So I started building a variation on this today! I'm cutting the "wheels" out of MDF, I have sized them so that they are 60 sided polygons with 4 inch sides, I'm going to make some sort of gantries to span between the mdf wheels, and then (when my makerbot gets here, darn 4 week lead time ) use some modification of the cages to hold the rock wool cubes that you have posted! I should probably create a derivative work thing page instead of spamming you with comments, but I want to give you tons of credit for inspiring me!

That's awesome, and I'm not sure if I've ever totally inspired someone before, but it's nice to know. ^w^

If using MDF for the ring, you might want to consider coating it with something waterproof so as to prevent warping from any moisture that's around, and if you use it for the trays that dip into mineral solution, it's an absolute must, otherwise you'd end up with rotting wood within a week.

As for a shop-bought drip tray, if you can find one the right size to allow the hydroponic medium to travel through it, it should be a simple matter to design a support for it.
As each ring in my design is 170mm deep and the frame takes up 40mm either side, by my calculations you should be able to
comfortably fit a 5-ring cylinder over a base spanned with simple 1m studding.

However, at that length I would expect any lightweight material you use to sag slightly in the middle, and it might be best to have some studding through the holes in each segment as well, instead of clips or bolts (the
reby adding a bit more weight and possibly requiring a more powerful motor).
I would probably guess you could use clips for two rings, and bolts for three rings in a cylinder, but above that you would probably need studding through the full cylinder length to maintain rigidity. But then that's why I
'm going to test this too, to find out!

Do link your derivative in here once you document it, as I'd love to see it. :)

I just realized I should also clarify that i'm only putting one large and one small on each end of the cylinder, that way I can clamp an entire row down between 90 degree aluminum and u channel aluminum.

I got the rings cut today, I'll put up pictures tomorrow! I made it as a 36 inch interior diameter and am planning on only making it 2 feet wide. I'm in a small apartment now and i mostly want to test viability/growing costs for various vegetables. I made two sets of two sized rings of MDF, one th
at the angle iron spanners attach to, and another one 12 inches larger that will rest on the rollers. I'm going to either use outdoor paint, or some sore of epoxy to seal the inner ring, and then i'll probably stain the outer rings because I think that will look nice, and they shouldn't have any dir
ect water contact so that should be enough protection for a couple years at least.

I'm thinking for the spanners I'm using two pieces of 90 degree aluminum like this -
gt; | |

I'm thinking of printing some pieces like this:
(Front view)

and then putting some U shaped aluminum across that channel on the top that bolt will bolt onto the outer rings which I'm hoping will clamp the rock wool in place against the 90 degree aluminum

____ _ ------------ _

I'm thinking this was I can secure an entire row of plants with two wing nuts and the design should be able to scale up to larger widths.

I'm not sure if my asci art and descriptions are legible to anyone but me,
so i'll put up pictures and diagrams Monday or Tuesday.



^*| ----------|

^*|---------- |


Added ^s and *s as padding so the asci doesn't break.

Also I just saw the new renders of the three rigs ones. Thats what I would love to build, but I feel like that would take months to print =/ ...unless you repraped until you had like 16 printers going at once ;)

Added a simple frame to support a board of lights after some other dead-end concepts, and 45-degree supports for extra rigidity. Will make STLs and upload after sleep :-P

Now designed some supports for a feeding solution tray, and an easier way of clamping segments of the cylinder together using custom clips. Uploading STLs, IGSs and DXFs now. More instructions and drawings to follow. :)

Minor edit: made the tray supports slightly longer to accomodate different trays.

Uploaded an angled light mount part that bolts onto the light mount beams, to support 45-degree angled batten lamp holders, like the cheap ones I have, so as to keep CFL bulbs on the cylinder's axis.

Added the parts list for a 1-ring cylinder, assuming you've only put 12 plants in like the picture; you can simply scale the numbers here up to whatever you want.
The segment joining pin parts can each be replaced by an M4x30 bolt, 2 washers(optional) and a nut if you so wish. You shouldn't even n
eed 4 for each segment either, 2 ought to do it, as the whole ring should be compressing itself together.

Uploaded an executable eDrawings file that should allow you to look in detail at any part of the construction and take whatever measurements you want. It should work on any average win32 workst
ation (the graphics card I got as a freebie a few years ago struggles with the whole model) and I would hope wine for linux will run it too, but I don't know if it needs any .net updates, or java or directx or whatever.
Anyway, have fun!

Can any electronics/physics geniuses on thingiverse work out what a good mix of LED colours would be to meet this: http://en.wikipedia.org/wiki/Chorophyll#Spectrophotometryhttp://en.wikipedia.org/wiki/C... and how many would be needed in series in each polarity to run at 110V or 220V.

Also, how many lumens of light could be expected from a given number of cheapo LED's?

For the moment I intend to use CFL's with this, but I would be very interested as to whether the system can be made more efficient with an array of LED bulbs suspended across the middle of a cylinder on a tube.

The last chevron won't lock! ;-)

They used one of http://omegagarden.com/http://omegagarden.com/ s models in the hydroponics bay on Staregate Universe! Apparently one of the set designers had herd of them and thought they were supper futuristic, he didn't realise it looked like a stargate until on the omegagarden staff asked him if thats why had picked it ;)

I might model a DHD just for you. ;)