MVP - Product Design


#64

@rbaynes
Your outline for the MVP looks good, though I am still debating software. I have Particle running on the Raspberry at the moment, but beginning to question its value (for immediate needs).
It turns out that if you start programming the pins without associating them with the mobile app (Tinker), the mobile app then tells you that you are running a non-Tinker app and will not show any pin information. And while the console if fun to watch, it is not really adding any value (now that I have local file logging working).
I am not ready to abandon Particle just yet, as it would be ideal for filling the reservoir remotely and other such IoT activities. However, now that I have it working, I think I will try porting the code over to Python and see what I can do with cron.


#65

@webbhm have you gotten as far as to plan the UI? Does it look like what @wsnook is using for charting could be used by us, or have you found something within Particle or another off-the-shelf platform?

I have discussed the Android phone hack idea for a controller with @webbhm previously and he has used it on projects, I’m fairly certain that you can run Raspian on it (I may be wrong). I think the “deploy or die” mentality of the media lab definitely has a history of getting its inventions to those in need. One of the most notable examples of this was the One Laptop per Child program. I don’t think OpenAg has any intentions of only developing things only for privileged wealthy people, just look at the WFP in Jordan.

I agree there are ways to do all of this cheaper than currently being done. I welcome another “MVP” attempt that perhaps is aimed at a different user (non teacher, perhaps more DIY, smaller, cheaper).

I plan to release initial BOM and an outline (hopefully github) of the Software by Thursday!


#67

@wsnook that is very dissapointing to hear. Do you mean in regards to the MVP conversation, or your acitivity on the OpenAg forums in general? The insight you have provided into many topics and the passion contributed to this project are going to be missed if that is the case.

It’s none of my business, but may I inquire as to what has changed and why you don’t plan to be around?


#69

Thanks to @drewthomas89 for posting the initial BOM to this thread: [MVP - Alpha Release]
(MVP -Alpha Release- Bill of materials).

We’re also planning to test an aeroponic reservoir this week using this pump I hope to be able to make the MVP aeroponic based on @yusuf.khan.su’s initial comments. I really do agree that it makes sense and quite frankly still don’t understand why the PFC V2 isn’t aeroponic. I am working with someone locally who has successfully built an aeroponic food computer successfully. I would love to get the advice of anyone else with experience in Aeroponics on whether or not they think this pump will be sufficient. @Atom @adam


Aeroponic System Categorization (flex/vertical/horizontal trays)
#70

I think you`ll find the noise level of that pump will be intolerable :wink: Pumps designed for reverse osmosis tend to be the most reliable and the quietest. I personally only use the pump, timer nozzle combo for cloner duty. The pump i use for the cloner is a 24v dc E Chen EC 204-50A if it helps, It runs 2 seconds on, 2.5 minutes off in the day and 2 seconds on 9 minutes off at night. Its supplied by a 3L bottle filled with RO water which is topped up daily as the cloner runs to waste.
For growing i prefer to use large accumulators which can run for days/weeks on a single charge. I use a single “mobile” 12v dc 160psi pump to service multiple accumulators.
What are the internal dimensions of the root chamber you plan to use?


#71

We actually haven’t made a final decision yet and are researching that exact question right now. Your thread on aeroponics has proved very helpful! I’m interested to know how you came to the conclusion that 15-16" is the minimum reservoir depth. Quite honestly, that’s the best example I have right now to go off of (any links/helpful materials you can provide would be a huge help). This MVP is designed for “leafy greens” meaning our roots are going to be relatively small (we aren’t growing “higher” plants). Our dimensions are the same as a PFC, which off the top of my head is: 23x20 by 32 high.

Could you please elaborate on what you mean by “mobile” as well as what 12v pump that you use and why you chose this option? I would really appreciate seeing pictures of your setup as well as any additional lessons learned you can provide us when designing the system.


#72

Hi Peter,
I would suggest using 15" root chamber depth due to the units overall height. The recommendation is based on practical experience of every kind of aeroponic system you can imagine ;) Over the years i have built, tested and refined many systems with the goal of finding the holy grail of aeroponics. Its been an interesting journey to say the least. The mobile pump is simply a pump that is not permanently plumbed into the system, the large accumulators can run for days/weeks on a single charge so a single pump can be used for any number of accumulators. I use 100L accumulators to supply large outdoor systems (16ft x 2ft chambers). The tanks are charged using a single "mobile" Propump DP 160 (12v dc) pump which takes approximately 8 minutes per tank. Once charged, the tanks simply run until they are empty. Maintenance is virtually zero with no daily ph,ec checking/adjusting, no topups and no need to dump a reservoir of spent/unbalanced nutrient because the accumulators are the reservoirs. During my journey i discovered a method of charging accumulators without any need for electricity using a (Rothenburger RP50) hydrostatic test pump which is basically a manually operated high pressure pump. Its not in service now as i have 5 other systems to keep me entertained but it is useful as a backup and comes in handy for pressure testing accumulators and plumbing, which is what it was designed to do ;) My "holy grail" aeroponic system has a temperature controlled root chamber and uses compressed air to generate the mist, its more than that but this post is long enough already. Ive no idea how to post pictures but rest assured your aeroponic goals are relatively basic and easily acheivable :wink:


Syringe Pumps - Peristaltic Dosing Substitute & DIY Aeroponics
#73

Using the dimensions of the MVP i would work on the assumption of needing less than one gallon of nutrient per 24hour period when running it drain to waste.The main issue will be how many plants you can fit in the available area so they dont crowd each other out.


#74

I am extremely impressed/interested in how you have been using one pump to “charge” multiple systems. To me this seems like a very efficient and innovative solution to maximize the value of pumps and eliminate quite a lot of power usage that comes with continually circulating pumps. Could you provide any more information about what sort of accumulators you use?

If you are ever inclined to post about this on your thread I would definitely take the time to read it in depth.

How many plants would you say is the limit (lettuce/leafy greens) for a 23x20x15 aeroponic system? Do you ever attempt to stop the roots from growing in a certain direction (wire mesh, barriers between rows, etc.) Also, would you suggest using the “full cone spray nozzles” similar to the ones found in BETE’s catalog? If not, what sort of nozzles do you recommend? I see there is an incredible variety, and I’m sure it varies on my goals. Again, any insight (even links if you don’t feel like typing) about how to choose which sort of nozzle would be very helpful when I’m designing this system.

What would you suggest to use for tubing? Have you found flexible solutions like PEX suitable, or more permanent metal distribution lines to be the best?

Honestly, your posts and insight, as well as conversations I have had with @yusuf.khan.su have really inspired me to pursue aeroponics in a much more serious way. I think it’s important that the community is aware and experimenting with this technology which is why I want to incorporate it as a part of the MVP. I sincerely appreciate your help so far and any other insights you or other experts on aeroponics lurking here can offer to help me develop a working aeroponic system for the MVP would be greatly appreciated.


#75

Hi Peter
My workhorse accumulators are Lowara 100L (10 bar) verticals with replaceable bladders, They hold around 40L of nutrient when charged from 80-140psi. I use pressure reducers to maintain a constant 80psi output pressure which provides a consistant nozzle flowrate and mist quality. .Without the reducer, the nozzle flowrate would track the accumulator pressure (high to low). Its easy to overlook these small but important details with aeroponics. The benefit of the one pump, multiple tank approach is the cost is somewhat offset by the savings on pumps, power supplies, pressure switches, pressure relief valves etc which are not required.You can fit additional accumulators to increase the system capacity at any time…
The holy grail system is for the truely obsessed aeroponic grower that wants total control over everything to the nth degree.:wink:
The number of plants will be dictated by the footprint of the light and the amount of space required by the mature plant. I would allow at least 5x5 or 6x6 per site,.
Ive tried root barriers/trellises (horizontal and vertical) and didnt find them beneficial as they tend to obstruct the mist. Id still recommend experimenting as the knowledge you gain from the failures is invaluable in the long run :wink:
I use a variety of nozzles geared to the shape of the chamber and the planting arrangement. For your small chamber i would recommend upward firing,wide angle,short throw, hollow cone nozzles. Hollow cone nozzles typically have a lower flowrate than full cone and the overlapping rings will provide good coverage in the limited space where solid cone will be too much…I use this type of nozzle in my vertical (leafy greens) aeroponic towers, 35 plant sites, 670mm max diameter and around 200Lvolume, They use 4 nozzle ring manifold (1/4" semi flexible nylon tubing) located about 15" down from the top. I can run 2 towers for around 4 days on a single accumulator charge…The towers are outside in full sun,so they do use more water than an indoor system where the environmental variables are easier to control.
You could write a book about aero and only scratch the surface ;).


#76

A minimum viable product (MVP) is a development technique in which a new product or website is design and developed with sufficient features to satisfy early adopters. The final, complete set of features is only designed and developed after considering feedback from the product’s initial users. Assignment Writing


#77

I tried to access your link but am getting an error. Could you please elaborate on your post?


Aeroponic System Categorization (flex/vertical/horizontal trays)
#78

I want to offer an option for the MVP, as well as anyone who wants to “upgrade” their PFC to HPA a way to do so. I appreciate all of your help so far and would now like to start working on this very small and simple HPA system. Keep in mind, my goal here is not to create the “holy grail” high-pressure aeroponic system. My goal is to teach people the requirements of a system and enable them to build their own down the road or at least have a way to get started for ~$100.

Pump - I know you said this would be loud, but frankly I’m willing to live with it for right now).

Pressure Gauge - I know I’ll want it when determining it for myself, but once we have it calibrated is it necessary? Do you think adding a pressure sensor hooked to the Pi would be possible? Has anyone had experience using Pressure Sensors with Raspi?

Accumulator - Will this be sufficient? I was also looking at DIY options, thoughts?

Solenoid Valves - Would this be sufficient, or is it too flimsy?

Misters - I plan to use a Hollow Cone mister. I’m looking at using BETE nozzle number WT10, which at 100 PSI provides 0.00266 gallons per second. My reservoir should be around 20 gallons of volume, with about 8 plant sites. Based on @Atom’s recommendation I want to deliver 0.02ml of liquid per gallon of volume for young plants, that’s around 0.000105669 gallons of water per misting interval. Perhaps I’m doing something wrong with my math here, I’m still uncertain on how to deliver such a minuscule amount of water though. Would it be smarter to use a misting ring? or should I be looking for T fittings like this that I can then attach nozzles to?

Tubing - I plan to use PEX 1/4 tubing I’m trying to avoid brazing or the user being required to have metal cutting tools. Secondly, what diameter tubing should I use? I know the pump starts as 3/8, my accumulator is 1/2, and the solenoid will be 1/4 (in theory I could go 1/2?). I want to go down to as small as 1/8 when I’m inside of the unit though (I think?).

I know that’s a lot of questions, but I’m learning here and I think this is one of the areas that deserves focus and would really appreciate feedback/help. If anyone is willing to prototype one of these systems as well that would be a major help for the MVP project.


#79

Hi Peter,
I looked through your list, the pump will do if you can handle the noise. Youll need to figure the deadband of the onboard pressure switch as it isnt stated in the spec. A pressure gauge is necessary for setting up, so you have to buy it anyway and it simply tees off the line so its no biggy to fit. The diy accumulator isnt much use, the air cushion isnt physically seperated from the nutrient and it has to be precharged to 2psi below the pumps cut-in pressure (which is unknown). The cheapest alternative is to look for a 5gal reverse osmosis pressure tank with a working pressure above 100psi. They usually have a 1/4NPT male threaded outlet and push fittings are readily available. The solenoid is ok for the job. The bete nozzle has a flowrate of 9.5LPH which is a lot. Take a look at option B on this page http://flsprayers.com/shop/tips-nozzles/hypro-af-series/ What you need is the anti drip version which have a ball and spring valve built into the nozzle. The easiest way to plumb everything is to use push fittings and ldpe (reverse osmosis) or nylon tubing. The best option for the nozzles are nylon tees typically used for pneumatics, these have a 1/8" male threaded center and 2x 1/4" push fits. Something like this https://www.stcvalve.com/Push_In_Fitting_Dimension-BT.htm With the addition of an 1/8" double female coupler the nozzles can be fitted and removed in seconds without any tools (the nozzle stays with the coupler). Heres a pic of the nozzle manifold in one of my 220L towers which use 4 nozzles. The tubing is 1/4" semi rigid nylon overkill at 400psi but i had lots of it on hand. I personally wouldnt use 1/8" tubing in a system as itll be more prone to clogging and it`ll incur significant pressure loss.

Your math is fine, the numbers are related to an ideal system that delivers 5-80 micron droplets and provides full chamber coverage. .


#80

Thank you @Atom, since size is somewhat of a concern, do you think the ShurFlo accumulator I listed earlier will work instead of a 5gal tank? I appreciate the tip about the tubing, the only reason I had been looking at 1/8 is because I was unable to find nozzles with a lower flow rate. That being said, I appreciate your tip about those nozzles and plan to utilize them!

Caleb tweeted this article yesterday which I thought provided a lot of very good answers to questions we had been asking throughout our development process. The primary one being “what is the objective of the PFC?” I thought this might be of interest to at least a few of you: @webbhm @TechBrainstorm @yusuf.khan.su @jimbell @adrianlu @nav @juhnke


#81

Assuming the pumps pressure switch operates 80-100psi. The 21oz (0.163gal) shurflo accumulator will give you a drawdown of around 100ml versus 3.3L for a 5 gallon tank.


#82

.
This is the cardboard box version of the MVP. Other than a latch for the door and cleaning up the wiring it is about ready for plants. I am going to let it sit for a couple of days while I monitor the software, but it is just about complete.
Total cost is below $300(US) with minimal tools.
Software is some simple python (source on Github). I am currently looking at how to modify the OpenAg UI so it will report and graph MVP data. Both systems are logging to CouchDB, so I am hoping this will work.
Within the next week I should get the documentation pulled together. The build instructions and other documentation will be on the OpenAg Wiki under the MVP.


V2 Food Computer Kit Build
#83

First and foremost, I’m very glad to see discussion regarding MVP development for the PFC. We’ll begin our PFC v.2.0 project in September. One thing we (Around The Bend Farms, Inc
) are discussing during the planning stages is coming up with an MVP. The one area that we’ll be focusing is a “home appliance” design and application for the PFC. The primary target market we’re looking to serve will be those who live in high-rise apts, condos, mobile homes, and who have restricted or no access to land. We’re in the process of developing a survey in order to gather data from the communities we’re looking to serve. We need to first determine if there’s a “need,” or else we’ll be chasing our tails trying to find if there’s a “need” to begin with.

Having been an educator for 8 years in the “Bay Area”, I understand that a big issue facing secondary schools is cost. I’m glad that you’re looking to provide a more inexpensive kit option so that schools can hopefully afford to build a PFC for educational purposes.

I look forward to further contributing to the MVP discussion, and I look forward to engaging in constructive dialogue about MVP creation!


#84

Not sure if you’re still in the Bay Area, if you are, check out this thread.

You mention “home appliance” as a product reference, which is a pre-assembled item designed to last a decade or more and typically under $1000. The technological equivalent to a V2 Food Computer in the commercial industry is similar to Leaf, which cost $3500, and have yet to deliver a product. The market they intend to serve is medicinal cannabis. The cheaper range under $500 like Niwa, or Aerogarden are more similar to our MVP in terms of capability. The third group in this market is Tower Gardens, I bring them up because they’re wildly successful, but for a completely different reason and have no computer integration. Their success comes from people having a desire to actually produce an edible amount of food similar to a garden, or for their use in education (5000+ in schools). I will say, if managed properly, they can definitely provide one with more than enough lettuce. I might also add that all of these groupings are pre-assembled (or extremely easy kits) and I would presume they plan to make the bulk of their profits from selling consumables (refills) similar to Kuerig.

One of the things we are discussing is the development of kits for the MVP. This is based upon a clear demand already both locally, and on a larger scale as well. I think this is telling though, that the demand isn’t for MVP Food Computers, it’s for MVP Food Computer kits. Here’s my point: A Food Computer really isn’t good for much other than education. That being said, it is an educational tool that can be used for a multitude of curriculums.

Please give your thoughts regarding our current MVP, constructive criticism is extremely appreciated. I looked at your site and it seems like your a 501c3, but your tone sounded like you’re interested in commercializing a product, I’m curious your plans for the future. I’d also love to know more about your team (size, experience, goals for the PFC project).


#85

Yes, my Company is registered as 501©3, but there’s nothing about
non-profit status that reduces our ability to develop products & services
for public benefit.

The first iterations of our planned build of the PFC v.2.0 will be purely
exploratory and for research purposes, as we’ll need to get our hands dirty
with the overall “getting to know the PFC” process. I think this is a great
platform to use for further development. Of course, one of the many steps
we’ll need to take is looking at how to bring the cost of production down,
but that gets tricky when there are “value added features” that we’ll be
exploring. I’m quite aware of all the neat gadgets that are currently out
there already, and it makes sense to follow their companies closely.

I really don’t have anything in the way of constructive criticism in terms
of what is currently being explored as an MVP. There’s nothing critical to
say without sounding reductionist, therefore I’d like to stick to simply
what is observed. I’m going to need to glean more information from the
forum postings to really understand the conversations unfolding about the
current MVP climate. I can definitely see a market for kits in schools, and
it makes sense to make significant design modifications to the PFC v.2.0.
to greatly lower the cost - let’s face it…not a whole lot of schools can
afford a PFC kit costing a few thousand clams.

My plans right now are to be part of the changing face of sustainable
agriculture, where we are now getting back to the roots of agriculture
being a community endeavor, where farming knowledge was a shared
enterprise. I think that the OpenAg Initiative is developing as a fantastic
platform for this to be taking place, and I want my Company to give its
2-cents. We are still navigating through the OpenAg materials, and planning
our PFC project with Oregon State University Engineering Students in
September.

If you’d like to know more about our team, then you can contact me through
our website link and go to the “Contact Us
http://www.aroundthebendfarms.org/production-contact/” page. My name is
Ben, and it’s nice to start a dialogue on this forum. I look forward to
having more discussion / conversation. Be well.