I am making plans for a greenhouse that will be built in 2021. I need some "macro" information to help me design the greenhouse and to show me what I need to start studying. The plan is to use bakers racks to as shown here to put the plants on.

Each tray of plants will have several sensors to gather key pieces of information, as well as needing to turn pumps, lights, co2 on/off, etc. Each rack will have up to 5 trays of plants on it. I would like to have some kind of hub or computer on the top of the rack to monitor and control what goes on in each tray and will also connect to the main computer to consolidate data on all of the racks. The racks will be moved around, but no more than 3' in any one direction. Power, water and connectivity will be from the ceiling. I am looking for ideas for the "hub or computer" that will fit on the top of the rack as well as the main computer. The racktop device does not need to have a built in human interface - make it as simple as possible. I would like to avoid the use of wifi here because I will potentially have a hundred of these racks and am a little bit nervous about having so many wifi transmitters in such a small area. Would rj45 work? What do I have to do to protect the electronics from the moisture and humidity?

 

That last sentence is a big problem! Greenhouses are pretty rugged environments for electronics. But let's put that aside for now.

Could you use something like this as your "hub"? It's a multi-port data acquisition device that can collect data and communicate over a number of interfaces? (I have a cheaper model and love it.) These aren't terribly cheap but they have a ton of features, good support and so on.

 

Write out all of your requirements, and try to find the sensors that you want to use, or at least the data that you want to collect and some potential sensors. It might turn out that a fully contained (potted) wireless battery powered solution would be most durable. A few hundred devices is not a lot these days. You could even use some very low power mesh networking; ZigBee, Bluetooth Mesh, etc.. These low power solutions can go a very long time on battery power (months, years). First define your requirements in as much detail as possible, then look for the technology to solve the problem. Choosing a technology first is not always the best way to go.

 

Choosing a technology first is not always the best way to go.

Ditto that. I also question the plan for monitoring at the tray level instead of the rack level or even entire-greenhouse level. What questions do you hope to answer with all this data? Or, what is the actionable data?

 

Sounds to me like you need to visit a large commercial greenhouse in your area. Are you in the US? If so, I can make a suggestion. What is your prior experience with greenhouses?

 

There is at least one publication dedicated to LEDs and horticulture. It arrived in my email and I looked at it briefly and ended the subscription. BUT a web search for it might get you subscribed and that may have some value as it was advertiser paid not a pay subscription. Unfortunately I deleted the editions that I got. Just mentioning that there are organizations already with a whole lot of information already. Even the ads show pictures of products so you could learn from what is working for others.

 

Thanks! Smart people here! I have no experience with green houses...yet. I am learning about hydroponics now by doing doing and reading about green houses. Not all trays will necessarily be monitored in the end. What needs to be recorded will depend on what is being planted. During the initial phase, while I am experimenting, I will probably monitor many more data points than when the system becomes turnkey. My initial goal is to try to make a model for people to follow that will provide a family of 4 (almost) all of their fruits and vegetables, which I will release in the public domain. It has been an interest of mine for a long time and a concern now for people who are trying to afford good, healthy food. The final plan that I submit will probably not be digital at all - using some locally available timers, simple ph probes, etc (as reasonably priced, reliable and easy to use as possible.) The things that need to be monitored are ph, dissolved oxygen, concentration of nutrients, amount and intensity of light. One way to make this more simple is to actually put the water in the bottom of each rack. That is the reason for starting out with these racks - they are really flexible. However having 15 gallons of water in the system means that all of the chemical levels will be more prone to change, not as stable as a 100-300 gallon bin of water. But it would make it easier for the average homemaker to scrounge parts for and set up. At some point, it will be helpful to know how to daisy chain the racks. Yes, YT has been my best friend lately

 

Thanks! Smart people here! I have no experience with green houses...yet. I am learning about hydroponics now by doing doing and reading about green houses. Not all trays will necessarily be monitored in the end. What needs to be recorded will depend on what is being planted. During the initial phase, while I am experimenting, I will probably monitor many more data points than when the system becomes turnkey. My initial goal is to try to make a model for people to follow that will provide a family of 4 (almost) all of their fruits and vegetables, which I will release in the public domain. It has been an interest of mine for a long time and a concern now for people who are trying to afford good, healthy food. The things that need to be monitored are ph, dissolved oxygen, concentration of nutrients, amount and intensity of light. One way to make this more simple is to actually put the water in the bottom of each rack. That is the reason for starting out with these racks - they are really flexible. However having 15 gallons of water in the system means that all of the chemical levels will be more prone to change, not as stable as a 100-300 gallon bin of water. But it would make it easier for the average homemaker to scrounge parts for and set up. At some point, it will be helpful to know how to daisy chain the racks...

My observation is that in almost every instance the primary motivation is PROFIT, usually from the sale of high quality product. There is a great deal of knowledge in existence as to which colors do what the best, which seems to be even more effective than what is fed to the plants. So the challenge will be to locate the information rather than to be recording data. Others have already done that, and universities are continuing to do that. Locating the information and implementing the knowledge in your own system will be the challenge. Data without insight is of a marginal value at best. So learn from what others have done. (Unless it is part of your doctoral thesis requirements)

 

Others have already done that, and universities are continuing to do that.

Very true. The chance of you uncovering something novel is next to nil. I visited a commercial scale hydroponic farm 40 years ago. The technology is well established and you don't need to reinvent the wheel. Go to your local agricultural extension office and start looking for resources. The first few people you talk to may not have much expertise or interest in helping you but keep asking for references and advice. Visit your state universities. There might even be graduate students that need challenging projects. They may or may not help you directly but they might collaborate and share experience with various technologies.

 

The publications with ads for the various products and reports on research results are he ones that I am thinking of. Universities seem to be only interested in money, so if you don't have large amounts for a research grant they do not have time for you. The leads started with "Laser Focus World", which is available on line.

 

Thanks! Not looking to discover anything new...looking to use technology transfer to find a model that is cheap, easy to use and understand by those people who don't have 3 initials after their names and who aren't related to either Bill Gates or Warren Buffet..

 

The defacto standard for instrument control is the program LabVIEW from national instruments. Colleges have site licences. there is non-commercial use license too. Very strange programming language. It's visual and you draw like you would a schematic. Each block or (vi) executes when all inputs are available. it;s an easy language to do parallel processing. A vi is a virtualinstrument and you can set up the program to serve webpages.

The standard industrial thing is the PLC or programable logiccontroller. You can marry the two. The PLC might have routines to control temperature and humidity where LabVIEW can do the sequencing or data logging. Other programs such as Wonderware can interface to PLC's/ There is another one being advertised in a trade pub I subscribe too.

 

With regards protection against moisture and humidity – the product safety standard 60335-1 requires that products designated for use a greenhouses have a minimum ingress protection of IPX4. Test to this level of protection is quite onerous, with the equipment sprayed with water from various directions.

If you must have the mains powered computer system located within the greenhouse, I would recommend you opt to use a laptop powered from a lump-inline power supply, which might comply with this ingress protection. Even then, it would be worth positioning the mains parts such that they are unlikely to have water accidentally poured on them.

If a laptop does not have the expansion connectivity you require for your control purposes – you could consider use of a mini PC, again powered via a lump-inline power supply; but again these units tend to have limited connectivity/expansion options and would need the addition of a display unit.

 

Hello,

As @Hymie said, when a computer is used, do not have a mains powered one.
A rugged computer might be an option:
https://www.tangent.com/industrial-computer/

Bertus

 

If you are using things that have been verified to be the best choices by those who have spent a lot on research, and your purpose and goal is not to do more research, but to grow food, why chase after all kinds of instrumentation and data collection systems? Especially the expensive software? Once you have verified that the lighting is at optimal wavelengths and that the watering is adequate, all that remains is the feeding, and that information is already available.. With limited resources the focus should be on the target. But if research is the goal then things are different.