Tank and PH+EC Set Up


Hi Guys, i am new on this plants stuff :grin:. The things is i am not having problems with the code+sensors+rpi+arduino set up . I am having issues trying to understand the set up inside the tank, example:

How much water?
water pump position?
PH and EC position? They have to be all the time under water ? ( i read on the seller’s page that they are not for “24/7” use)

so that are some of may douts, maybe i miss the file that explains some of this things.

I will appreciate any help.

cheers, Santi


your not the only one. The sensors in the BOM are not designed to be submerged at all times. This is a challenge with the FC1.0 design and throwing $$$ for better sensors moves the FC in the wrong direction. This is where the open community can be inventive and come up with better answers.

as for the pump position, see the youtube video, slow it down towards the end, you can see how they position the tube and pump.

dont know on the amount of water. I suspect, enough to reach the roots.


hi there @JoshSinykin thanks for the quick answers,

i will re-check the video.
So for this FC1.0 design i need to interact with the PH and EC sensors inorder to measure.

i found this sustitute for the pH http://www.dfrobot.com/index.php?route=product/product&product_id=1110&search=ph&description=true#.Vx-w9_l97IU

i will keep searching for a EC “24/7” replacement, and some hydroponic for dummies.



My recommendation is hold on purchasing the DFRobot sensors as defined in the BOM. You may be better off with a higher quality solution from another source… but then that will require some code updates to the openag microcontroller to support it. I have heard MIT media labs has already moved away from the DFRobot sensors.


It seems like there are more and more questions mounting on the actual growing portion. It would be nice if someone at OpenAG could contribute some kind of “getting started” wiki page. Most of us are geeks, not farmers so building this thing will com easy. The real challenge is going to be bridging the knowledge gap that exists between tech and this type of agriculture.


That would be awesom.


Thanks for the headsup, nevertheless i will buy those sensors, i want to know how much precision i need on my measures, and if the make a difference or not.


@JoshSinykin @ToeSmack http://www.hydroponicsetup.org/2010/08/diy-deep-water-culture-system/

that could be usefull



I’m one of the Food Computer co-creators (mech eng but heavy on the plant growing sideof things too :slight_smile:

It’s recommended to do 5 gallons of water - this is roughly 4 1/4" depth of water in the bin that’s listed on the BOM.
You can get away with less water for smaller plants (smaller roots), so this is definitely something up for experimentation!
The water pump can be suctioned onto the left wall towards one of the corners and the 6" piece of tubing directed along the side to get good circulation of the water.
@JoshSinykin is right, better (&submersible) sensors = $$$! For these, keep them poked through the foam so that the bottom ~4" are submerged but the top housing where the wires come out of is above the foam tray. One thing on this, though - since there is no feedback loop based on these sensing points in the V1, you could just take them out and put them in storage solution but put them in when you want to manually take measurements. Would need to go into the sensor history and do some post-processing of the data though.


Excellent info rcamille, keep the good info flowing! Most of us tip heavily toward the geek end of the spectrum so we need that farming expertise to balance things out!


Haha soon you’ll be tech geeks AND farming geeks. The more geek the better IMHO :grin:


@rcamille Thanks for the info, i will go shopping then :grin:


@Santi While it nice to have the pH and EC sensors, the system cannot adjust the water to fix an out-of-control situation with either. It would be just as useful to get a combo pH/EC meter from Hanna Instruments and periodically monitor.


@Rckco , yes i know, but i like making logs :grin: and then see all the data and study how many time day or week i will need to measure and bla bla.
Apart from that i make a project during college with a peristaltic pump and controlling ph in pools and big fish tanks so i want to bring something of that project to this one. I think that in this case a micropump will do the trick and close the loop.


@Santi Im using this pump for my dosing system. It seems to have pretty good reviews. I purchased 10 and they all passed a 24 hours burn in. Their output volume did get higher after the burnin but since this will be part of a controlled system, I think its good enough to try.

Here is another one. Looks easier to get a precise dose.


So you got a system built with these dosing pumps to regulate the nutrition solution?
Great idea :slight_smile: Even more nerd to the build :smiley:


wow, thanks @Rckco, i will definitely tray them!!!


@silversson Im building one. PCB’s are here, and mechanical parts are being fab’ed. It will be a month before I even get to the software to make the new systems functioning. I also added a custom grow light system, co2 injection, ph and fertilizer (via EC) control.

@Santi I have to give credit to @JoshSinykin for the stepper pumps he found on ebay.


very helpful piece of information. Is there a document some where that talks abut setting up of the yeast bioreactor, plant and water? i have one completed and would like make a working version before trying anything new.


We have our pH/EC/Temp probe available. http://www.plantcubed.com/product/openag-phectemp-probe/ . Software and schematics are available at https://github.com/Plantcubed/plant3_sensor_phectemp