Gantry & Tools Design: Vulnerable To Harsh Environments?

Why couldn’t the gantry pull a shade cloth with it as it goes and stay at the end of the track to provide the shade when necessary?

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There may be other types out there, but the only shade cloth I have used is a loose plastic mesh. It is not difficult for me, as an adult male, to move around. FarmBot does not seem to have a lot of spare “horsepower” if the present limiting factor in doubling it’s size is the weight of the cabling and carrier.

@leon.kemp yes, being an engineer from and having developed FarmBot in California I may definitely be underestimating extreme cold. In such a case it would probably be best to pull the gantry off for the winter and put it inside. This is actually fairly easy and fast to do: Just need to disconnect the belts from the tracks (4 screws) and the cable carrier from the track (2 more screws). Then the gantry can slide off the tracks and the whole gantry/power supply/cable carrier can be moved inside. It would take about 10 minutes to do.

Regarding galvanic reactions: usually this is taken care of by having a “sacrificial anode”, ie: a material that will ok if it gets eaten up. In the case of stainless steel screws/nuts on aluminum plates/extrusions, the sacrificial anode (the part that gets eaten up) is the aluminum, which is good because there is so much aluminum that if some of it gets eaten FarmBot will still function just fine and maintain its integrity. If the screws/nuts got eaten up, that would be a problem because there is comparatively a small amount of that material and any corrosion would directly affect the performance/integrity.

Thanks for both replies.

Belts are simple to remove when they are flexable and not highly chilled. Fan belts and other things in car that are thicker have records of increased snapping due to cold weather as warm as 5C.

This is part of a nightmare of globally doing a product. Yes removing gantry in the weather you are in most of the time is going to be lot simpler than removing the gantry in areas colder. So its something to have on checklist at what temperature does the choose belts become brittle different belts have different brittle points, Yes a temp sensor to make machine not attempt to move itself when it too cold for safe belt operation would be a add-on safety device for colder areas.

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I totally get that we want to protect our device against these cold weather conditions. But can you grow plants in those conditions? If the answer is no, then FarmBot has no place there anyways.

Not saying that colder areas in the world can’t benefit from FarmBot, just saying that those places (including my home) need to look at greenhouse solutions to not only protect their bot but also protect their plants.

They go hand-in-hand. If it’s too cold for FarmBot to operate, I think it’s too cold for the plants to grow.

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This is the extremely cold tough food crops list. Note the Leeks and Collards. Yes carrot will live down to -40C/F with some protection. Particular versions of Leeks and Collards do 0 °F/-18 °C without protection.

So to cover the full range of plants the lowest operating temperature is like -40C up in the top of frame because the surface of garden can have provided some protection so be warmer than the top of the FarmBot. Yes temperatures that will do in water lines and belts at times. Yes there are weeds that will live and grow that cold as well of course it could be a serous test attempting to crush a weed into soil that cold. I have a feeling that currently Farmbot is not tough enough to keep up with the conditions plants can be grown in. Of course it not much to add a few sensors to go ok this is too cold don’t move. With those very low temperatures the day temperatures will normally be warmer so there will be safe windows for the machine to operate.

The lowest crop growing temperatures is a lot lower than most expect.

If it were snowing or frozen out, would the plants even be alive if they were not in a greenhouse?
The answer is yes if the correct varieties will be alive and growing in snow or temperatures when rain drops can freezing on contact covering everything in ice(what is a worse nightmare for farmbot than snow). Snow fall starts as early as 0C to 2C and snow can act as a protective blanket against even colder temperatures.

Yes Leeks and Collards in snow photos do exist. With Leeks the closer the temperature is to kill them the higher their sugar content will be so the sweeter the Leek will be they use sugar as antifreeze. Above 0C weather will not make leeks that taste as good. Found out about this attempting to grow them subtropical and wondering why they were not sweet.

You don’t want enough snow to bury the leeks so they cannot get light but a inch or two will not hurt them. This is the problem some plants are just insanely tough and worse to get results you have to grow them in those conditions.

That’s all wonderful (and I honestly do not mean to sound condescending), but FarmBot isn’t well suited to produce corn and other high plants. I think similar restrictions will apply to temperature.

We will have to accept that some crops are better suited for FarmBot to grow and others are not. I think our first goal should be to build the Genesis model worldwide and learn our lessons from it before we attempt to over-optimize it for all sorts of crops that right now seem ill-suited for Genesis.

Perhaps once a great number of people are using FarmBot and sharing their experience with the community, we will be able to design a new generation of FarmBot “Exodus” that can handle higher crops, colder / tougher crops and such.

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We get cold temperatures here for 4-5 months of the year. That means we have 6+ months where we CAN crow a wide variety of plants. FarmBot can still be valuable asset for people with busy lives that still want to have fresh home-grown vegetables. It would just be necessary to “prep” it for the cold like we do everything else. Blowing out the water lines, and providing some basic protection over the cabling and railing, plus a “storage shed” for the computer gear would be plenty.

Part of it come down to how valuable you view your time at home. This is what actually determines the payback time (in concert with the value of the produce.)

On 1. Would you have to worry about left over liquid in the pump freezing? I was thinking that a second reservoir could be a feed into the tubing system (with a switching valve) that you then could put any secondary fluid through that you want. Maybe an liquid that does not freeze easily. I was thinking about it for compost tea but anything would work.

On 2&3. I would only add that I think the bay you are talking about should be mobile. I know that sound unnecessary and it is for your idea but when combined with other ideas it could;

A. Have its own motor to provide the hp needed. Adding more hp would help some with the issue people would have with cable weight in larger systems. It could either be wire into the main system or just have a hookup and switches to have it start and stop when needed. It could have an automatic induction charger at its home port, if its to be a separate item.
B. Have other locations for bins. Compost, other liquids, storage for harvested items. The amount of time and effort a storage location that moves with you during harvesting would save you would be crazy. My father is a 64 year old disabled man (back fused and two heart attacks) who does his own farming and something like this would be world changing for him.

On 4. Have you considered a cable system. Two cables taunt above the grow bed (running parallel) and sections of shade material supported by zip line trolleys. It could stiff leading and training edges and loops or handles that could be hooked onto by the farmbot arm, once you add a handle sticking up from it to do so. This might provide shade while staying out of the way of the worker and farmbot system.

Just my thoughts, I sympathize with your difficulties.

Yes. You are best to completely drain a system before the cold weather sets in. That is why the standard practice is to fully blow out a system with compressed air.

It is important to remember that water expands on both sides of 4 degrees Celsius. I used to work in the soft drink industry, and if a bottle of pop was frozen, it would sometime be fine until it started to “heat” back up to freezing, and THEN would explode.

As for fluids that do not freeze easily: I have seen (not in the last couple years, but we are expecting a cold one this year after El Nino) temperatures of minus 35-40. You need a good antifreeze to stay fluid in those temperatures.

Making the bay mobile introduces another level of complexity, and would require a fair bit of work in the code. There may be simpler solutions. I believe that a lot of the concerns with increasing cable length is actually dealing with the drag of the cable tray. You can buy UHMW tape (http://www.leevalley.com/en/wood/page.aspx?p=32182&cat=1,110,43466,32182) which could be applied to the cable tray, and cut WAY down on drag.

I tend to harvest what I need for the next meal. Now, there may be SOME people that want to harvest and preserve, or (like your dad) have mobility issues. Again, I look at the changes that would be required in the code (including making it configurable) and am not certain it is justified. It may well be, but just not for me at this time.

The cable system for the shade cloth has some definite potential.

Thanks for the input!

I never knew that tape existed ty I love new things!

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1.5m is the max set able height of Genesis and leeks and Collards are 90 cm. So they are in the physical handling size of the Farmbot.

The big point I was making mdingena is the durability range to test across. If something is not durable at a particular temperature it need to be noted.

The starting temp for durability is -40C because even with some protection at ground level no matter the plant it going to be having issues. The other end is 60C.

To cover everything is basically -40C-60C. Of course I don’t expect first generation Farmbot to cover this complete range and it might be impossible but you need to know what is max range you are dealing with to know how far to test things.

Now to start of with most NEMA17 motors most are rated for a ambient temperature of -20C to 50C to operate. Some makes will tolerate hotter and colder as long as they are not operated at those temps some will not at all as bearing in them fail if too cold or too hot. So that is our first limit. Rotatory sensors and belts used can have a smaller range.

The 3d printer control boards are fairly tough -55 to 125degC max arduino with a sure safe from -40c to 85C and the rest of the parts on most ramps boards match or exceed this. So there is a problem here that the ramps board can attempt to drive the motors when ambient has gone the wrong way. Altering for cold conditions would mean putting a temperature limit here so ramps loses drive power when temperature goes outside motors operational rating.
https://www.raspberrypi.org/help/faqs/
But here is a kicker raspberrypi choose lan chip only does by spec 0 to 70 C the core chip does -40-85C. So the rasberrypi could kick the bucket before the plants do. Particular models of Beaglebone blacks are used in places because they have -40C to 85C ratings for the complete device. So cold conditions possibly swap the rasberrypi for something stronger or mitigation.

So going under 0 at the raspberrypi would require heater to prevent it getting too cold. Mind you the enclosed box trapping the raspberrypi own generated temperature can extend that range down question by how much and it would not be that hard to add a heater to the box. Now if the raspberrypi and other parts need heating in cold to stay safe even when taken inside a non heated shed it may have to stay connect to power to keep self safe.

The aluminium/stainless steel frame design will with no issue cover the -40-85C so -40 to 60C tempetures are not going to break it. Now what rating are the bearings. 3d printed ABS plastic parts are -50C to 90C(where it can soften slightly so its fine). So we can tick framework off. Bearing and the like are normally changeable for stronger ratings or it could turn out the default choose parts exceed the rating.

I don’t know that the power supply, cameras, rotary sensors and the belt tolerance is.

Doing all these numbers are important to know if a farmbot has got missed treated or in cold areas they get hit by a cold snap so fail to take the machine in what parts do need to be inspected for breakage. So it fairly much go part for part getting its rating and making a table. This also lets you cost compare to make stronger as well but you also need to know what the max range was to work out over kill. Yes just putting farmbot in a shed that is not heated with some of the current parts in a cold area might be fatal to some parts. So take inside instruction without doing this means you don’t know what the min storage temperature is to keep machine in working order and if it will be required to be powered to run heaters to protect stuff or in heated storage. Like with the water lines time can be bought by having a drain point in garden bed where the gantry parks with the watering valve being turned on and off. The pulsing of water will prevent the lines from freezing up part by changing the water over part by the action as long as the computer can operate at this point to perform mitigation actions. Of course machine performing mitigation you will want it sending distress calls problem with rasberry pi LAN controller is it might not be able to.

Tempeture tolerance is design and planing. Something things you can fix by improving parts some-things you fix by programmed operation response.

Harsh Environments does not have to be that harsh. Like shove current farmbot gantry in a hurry in a cirtus cold storage room here would absolutely risk the raspberry pi and I am in a fairly warm area. So cold rating is critical to know particularly if long term is farm scale.

There is something handy here we are not talking that specialist of equipment to test the complete range. Most house hold deep freezes go down to -40C and that is the bottom of where we need to test to and the top is in low temperature cooking range so testable with mostly house hold equipment.

Personally, I do not plan on gardening at temperatures below 0 Celsius. Although I HAVE grown leeks, I tend to grow more beets, carrots, chard, lettuce, onions. These are killed at -4 to 0-6. Once overnight temperatures are hitting that, I don’t see a lot of growth in the day. (That being said, Calgary weather can be HIGHLY variable. We can have overnight temperatures one day of -5, and 2 days later have daytime highs of 25. Google “Chinook winds”. I lived through the most extreme recorded one of these. Saw a 100 degree Fahrenheit temperature change in 2 hours, from minus 35 to plus 65.) That aside, I have no issue with taking care of the little weed growth that would be happening.

Based on what you have identified above, my plans would be:

Protective shielding over the belts and rails.
Blow out water lines with compressed air prior to hitting 0 degrees
Have a “shed” that can cover the Z axis assembly.
Remove the controller once the Z axis assembly is “put to bed” in the shed.

In the spring, it would just be case of

reinstall the controller
Remove the winter covers
Wipe down all surfaces
Probably use some penetrating oil on the bearings
Get the Z axis assembly out of the shed.
Reconnect the water, and purge the lines of air.
Fire everything up and reinitialise.

Did you miss my note Raspberry Pi 3 anything under 0 would be going outside its lan chip safe operating temperatures. One chip out of temperature on a board can make the complete board unstable. So you maybe looking for a stronger alternative to the Raspberry PI. Its about the weakest part I can see. Still I would recommend going through the complete parts list systematically. I only did a rough look over and I found one issue for that range.

If you stay with the Raspberry pi 3 you may want to add a heater inside the controller box. Basically if PI get under x temp turn heater on. Sticking around 4-5C bottom temperature for box housing PI would keep you clear of lan chips limit. Quite a simple mitigation. Now if you were wanting to operate down to -20C it would be replace the PI no matter what. I have not checked the camera and and a few other parts what their limit is.

No, I did not miss it. Perhaps I was not clear enough, but my plan was to remove the controller prior to forecast temperatures hitting zero.

Okay I have a probably unrealistic but fun to think about idea for year round cold temperature growing. (It would only extend the growing season in places like Alaska)

Plots that are:
Subterranean Rows to get below the frost line.
Skylights with reflectors to keep light levels up. (If you make DYI vacuum sealed then BP)
Skylights edging would drain water into pre-farmbot reservoir.
Heating if needed could be easily accomplished with soda can solar heaters or vacuum tubes.

Just random ideas

Ok ran into some issues and things have been super busy around the shop lately with new product releases at the end of the month, but I got some results on ASA! As a note, all our testing was done on an Airwolf Axiom printer using Cura to slice. Extrusion multiplier should be 100% for really strong parts about 97% for high detail. Your top layers need to be pretty quick at 60-64mm/ sec. Layer heights work at 200microns but its best to shoot for 180microns for roughed out mass pro parts. Basics are 248C for the hot end 120C bed temp full enclosure works out well. 1mm top and bottom shells with 2 perimeters, 34mm/sec interior perimeter, 40mm/sec exterior, fan 100% for bridging off otherwise. I recommend using Wolfbite classic bed prep for ABS PETG and apparently ASA.