This project tries to realise a full fledged indoor gardening System with the main focus on food crops that are normally not suited as indoor plants and provide them with everything they usually have in the outside world.
There are approaches to this problem but most of them rely on having a large basement or are otherwise very space consuming and try to re-invent containers for plants making the system very expensive and visually unappealing, although that is of course subjective.
I want to create a minimal in-expensive solution, utilizing existing containers for plants e.g. standard plant pots and breeding boxes. All you need to add to a breeding box or plant pot are metal rods which have an already accepted aesthetic in gardening as structural support for plants.
There will be modules for providing, light, ventilation, water, fertilizer and sensors to monitor plant health. They will talk over the center rod using the SDI-12 bus, with one module being the central "brain
This project is based on previous years entry: #MoRaLiS: Modular Rail Lighting System . This project advances on some of the basic concepts of MoRaliS and turns it into everything that is needed besides lighting. See my project logs further down for my progress. Unlike last year I try to document my process a little more and will try to write an entry for every step I take to realise this project.
At the moment I try out the concepts I have in my head, so you will see a lot of CNC milled boards at first, trying out different things. When I got an idea how everything looks I will proceed in ordering some PCBs to test out looks and get better data on mechanical stability. As it is starting to get warm in Europe I will also start a controlled test by growing a tomato plant of the same strain indoors with MoAgriS and outdoors on my balcony using the traditional methods, e.g. the Sun, windy weather and a watering can.
So if I caught your interest, subscribe to the project and follow me along :)
Running my first test with the tomato made me quickly realise that I will need some kind of motor module to move up the arm that holds the light modules as the plant grows otherwise you will have to adjust the light position every other day.
I already have a design in mind, first I thought about adding a threaded rod in the middle but that makes keeping electrical contact with the rod a bit hard as the fuse holder can easily grip into the threading and either make the module stop or jump of the rod and loose connection.
Instead I will leave it as is and use a clamping mechanism to press motor with a U wheel bearing on its shaft against the middle rod with a second U wheel bearing pressing from the other side. Somewhat similar to how some 3D printers grip onto and move filament into the nozzle.
I'm not sure on the motor style yet. I don't think I want to go for high precision in any way but having +/-1mm precision would be nice because then you could use this platform for really large cable free CNC portal setups! Think about it, the motors can get control signals and power over the rods that give the whole thing structure. You could easily built a few meter long setups on your ceiling without needing a huge cable track moving along with it. I think that could be really powerful.
So I was thinking of either using small stepper motors or drone BLCDs, they are pretty cheap, small and have high torque, potentially moving heavier loads quite quickly. With very few steps they lack precision but you can use encoders to mitigate that and actually make them really precise. Though I will probably go with a more low cost sensor solution to stick with the style of the project. If it doesn't work out I'm fairly confident that standard steppers will do the work just fine.
My experiment started a few weeks ago to see how the growth of a tomato from the same pack of seeds would compare by being grown indoors with MoAgriS vs. being grown outdoors in the sun.
The difference is quite staggering. Even though I live in a very mild area where there is even wine growing and the fact that we had the warmest April in the history of temperature recording; The outdoor tomato(s) are very far behind compare to the indoor tomato.
Both plants started out as seedlings in the inside grown with the lamp modules, when it got regularly over 20°c outside and not much under 15°c at night I put all but one tomatoes outside in a spot that would get sunlight all day. While the indoor tomato would get light for about 10h a day (which of course comes with a slightly increased energy bill vs free sunlight outdoors, so if you can grow outside, I always recommend that economically and ecologically wise).
On the left you can see the outdoor tomato, on the right the MoAgriS grown tomato.
The difference is quite staggering. The indoor tomato is about twice as large, same goes for branch length.
Though it remains to be seen how much this will affect amount of fruits and if the indoor plant will develop fruits at all. While the stem thickness seems healthy for the indoor plant a large plant does not necessarily mean that the plant will bear a lot of fruits, it could also mean it tries to reach the light and puts more energy into growing fast and produces a very thin stem..
Though I think this time around this doesn't seem to be the case, usually the plant will bend towards the light when there isn't enough and the light source is not perfectly above the plant, when I offset the light position for a day the plant would not alter its growing angle or the angle of its branches to get more light.
I did some measurements with a lux meter to see how the new LEDs mentioned in an earlier log perform in terms of light output. The results are pretty great. I measured more than 40k Lux on two 3W LEDs 5cm away. Still far away from the brightest sunlight which is about 100k Lux but given that you never get a perfectly sunny day every day and you can easily add a few more modules to the plant to maximise light output.
I think is might still perform better than growing outside given the consistency of the light output and the consistent warmth inside, plants don't grow if the temp. drops below a certain threshold which is around 15°c for many plants growing in the Mediterranean.
I did not use the automatic watering for this particular plant so far as the water consumption at this stage is very minimal and the sun is not drying out the soil so you only need to water it every few weeks, not a very good test case for watering but this will change once the plant hopefully start bearing fruits.
I designed a a first prototype for the PCB that will hold the pump and also be responsible for controlling it.
I wanted the pump to be just as integrated into the system as everything else so I didn't want it to sit somewhere on the floor but rather sit on the rods as well. So it was also kind of obvious to integrate the pump into a PCB together with its controller.
I gave spray painting a pot clamp a shot to see if giving it an effect color that matches the pot could look nice. Here a try with terracotta spray paint. I gave it first a layer with spray filler, sanded that and then a layer of primer. I think it actually came out quite nice.
They are small enough so you can actually mount them on the metal rods as well which I will do next! For now I just put in on the floor to test my tube clipping mechanism. Here is a full video showing everything:
You don't have to put it on an extra arm of course. Here it spraying from the top, from the same the led module sits on. The fuse clips are perfectly comfortable holding larger loads, you could probably add two more light modules without any issues.
While the brown PCB angle and the Samla box is not exactly winning any beauty contest I'm very satisfied functionality wise. The Samla box serves as a second stage for the young plants after they grew to big for the breeding box, after that they will get their dedicated pots.
The 3D printed clamp was nicely adapting from a pottery pot to a plastic box without any adjustments to the design. It holds very tight and is able to support the 70cm long metal rods just fine.
I added the clamping mechanism of the first clamp design to the top of rods to give them more support, otherwise it was very easy to jiggle a rod around with your hands due to the long length of the rods, now they are sitting firmly in place. I will design an additonal minimal clamp similar to the one for #MoAgriS: Modular Agriculture System to give support for long rods like these. I think the design should scale well to 1.5m and longer.
The plants are enjoying the light so far. For the estehtics I think having a proper PCB with probably white soldermask (or none and just have tinned copper for an all metal look) will go a long way to improve the looks. I think an all metal surface finish could give the setup a very nice industrial kind of look. Though for the plastic parts I would stick with white or for the clamp maybe go with the color your plant pots are in. I ordered some terracotta spray paint and see how that works in conjunction with my terracotta pots.
I just discovered something very promising. So called "new full spectrum LEDs". They promise a similar good spectrum for plants but are not fully plant focused like the usualy "full spectrum LEDs" which radiate a pinkish red color which is really not something you wanna have in your home unless you really love that color.
So what I did so far is mix every full spectrum LED with a standard cool white LED. This product now seems to combine the two in one package and just add enough green and blue to make it a comfortable light color. Right now they cost a bit more but that would be very well worth it.
While the solution I have works, its not perfect, in certain light angles you get fringes of pink when the light hits the wall around the plant and you don't have a lamp shade on.
The "no harm to eyes" should not be mistaken as an actual harm to your eyes, more in the sense of, it looks really bad...
I've been designing a parametric model in Fusion 360 (view or download) that can be easily adjusted to different plant pots. The first iteration was quite a fail. I totally disregarded the fact that plant pots are circles (well at least the vast majority) so it ended up only fitting with one of its clamps.
Not exactly as intended...
It was also very bulky which I didn't like so I scrapped that clamp and designed a new one that was more compact. I stay with the initial concepts of having two halfs that are screwed together to clamp the rods in place.
This is how the new design looks like. It fits nicely on its intended pot. I gave about 0.3mm tolerance which I think weren't necessary, having a snug fit or even undersizing it a little might be beneficial.
I messed up the dimensions for the hex nuts, they were way too small. I ended up hot pressing them with a soldering iron which worked suprisingly well.
And this is how it looks on the pot (see below). I'm quite pleased with the result. It's compact but is still very strong. The two bottom screws have two functions, first to give more strength in the case of lateral force where the plastic at the top screws might snap and second to deal with pots that have a weird shape where you may have a fat lip at the top or non linear curvatures.
In that case you can choose longer scews than needed (M3x12 countersunk) and screw them in deep enough to hit the pot to give extra support in these cases.
And here a "full assembly" with angle and light attached.
I made a minimal SAMD11 breakout for testing communication on the actual hardware. So far I just tested on some dev boards. If you haven't read anything about the SAMD11 so far. Let me give you a little taste of its specs: 16KB Flash, 4KB SRAM, 5-8 ADCs, DAC(!), RTC, up to 48MHz with external crystal, 12-22GPIO and 3 SERCOMs (UART, SPI, I2C for your choosing) and all that four about 1$ in single quantity. Apart from a load of legacy supported libraries, there is not much that speaks for the ATTiny85 anymore at this price point and size. If you wanna know more here is the datsheet.
Thanks to the wonderful work from mattairtech there is already a BOSSA compatible bootloader and Arduino core for the small and cheap ATSAMD11C14A which comes in a very easy to solder SOIC-14 package. Apart from a stable supply voltage the IC needs absolutely no other components to work, even when using USB it can use the internal clock sources!
My board only has a 3v3 LDO and a 10uF cap at the input and output of the LDO. Right now it even behaves great without a 0.1-1uF decoupling cap but I will definitely add one to the actual module designs. I just didn't have one rated for more than 24v in stock but nice to see it is able to work reliably with basically nothing. A true competitor to the ATtiny85. I'm hoping more people will adopt this wonderful MCU.
And yes USB works even if you don't give a shit about routing the traces anywhere close to each other or length matching them in any way. Its USB 1.x speeds after all, not terribly much to fuck up there.
(don't actually do that though, you should give at least a little care, I just knew that I will be ok in this case. Length matching +/-2.5mm will work out just fine at these low speeds, don't worry too much).
I iterated on the first angles and simply made them a little longer and doubling the amount of fuse holders. This makes for a very robust solution that can easily hold two large lamp modules.
I'm quite satisfied with the current solution. I jig would be nice for soldering though, it's not very easy to solder them at perfect 90° without something to hold everything in place. The one you see below is more of an 80° angle.