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    Thieme Hennis
    @hennis_twitter
    hi all, here Thieme from the Netherlands - I'm from the AstroPlant team which is a project we do with the European Space Agency. We talked with Rikuo and Rob yesterday. We may be posting some questions here and hope to contribute to OpenAg (although we currently have a different stack, we look for possibilities for collaboration).
    Rikuo Hasegawa
    @sp4ghet
    :)
    Thieme Hennis
    @hennis_twitter
    PS. we also are planning to open source all our designs, but we still need to figure out what direction we take (RPi, BeagleBone, Arduino yes.no)
    first question: what is the reasoning for not using the DFRobot EC / pH sensors?
    byebye!
    Rikuo Hasegawa
    @sp4ghet
    Not sure if @jakerye still lurks around but pinging him
    Rob Baynes
    @rbaynes
    The decision to switch from the DFRobot sensors to the Atlas ones predates Rikuo and I. I will ask the older team members and get back to you (will take a few days). Please remind me if I forget to post their reply.
    Thieme, this our wiki, which our community members help maintain (but it is mostly us). There is a link on it to our forum too. The device you will be interested in is the Personal Food Computer v2.1 (latest release). That page on the wiki has the link to our github repo and build instructions (hardware and software). https://wiki.openag.media.mit.edu/
    Let me know if I can point you at any other info!
    Thieme Hennis
    @hennis_twitter
    ok thanks
    Jake Rye
    @jakerye
    DFrobot sensors were noisy and unreliable
    SidneyNiccolson
    @SidneyNiccolson
    Hi there, I'm Sidney one of the software developers from the AstroPlant team. I have been investigating EC solutions and have a couple of questions as to why DFrobot sensors are unreliable. Q1 Was there a PH sensor in the system during testing? If so you need an isolation module that is available at their site, which prevents noisy measurements. Q2 there is a calibration procedure to make sure the readings are accurate, did you follow this procedure?
    Rob Baynes
    @rbaynes
    Hi @SidneyNiccolson ! @jakerye is on vacation, so his reply may take some time.
    SidneyNiccolson
    @SidneyNiccolson
    @rbaynes Thanks for letting me know!
    Jake Rye
    @jakerye
    A1 - yes, but they were isolated. A2 - we did follow the calibration procedure....We deployed the sensors in 6 units. Only half of them gave consistent readings. We didn't have much time to go very deep into the sensors so getting a few and seeing what you can do to explore a lower cost solution could be worth the time. A member in the OpenAg community, Rich Klosinsky, dug deeper into a better ph/ec/temp unit. Check it at plantcubed.com/product/openag-phectemp-probe
    Not sure if he's still actively trying to sell the unit, if not you might be able to get the design files from him. Regardless he's a nice guy and worth reaching out to
    SidneyNiccolson
    @SidneyNiccolson
    Thanks for sharing! I'll reach out to grow@plantcubed.com. Any idea why OpenAg PFC has no integration of that unit? Atlas Scientific is high-end, but are in turn quite expensive.
    Rikuo Hasegawa
    @sp4ghet
    We prioritize high quality measurements over cost generally. Also, the atlas sensors are much easier to source since they are mass produced.
    SidneyNiccolson
    @SidneyNiccolson
    I understand @Spaghet
    Rikuo Hasegawa
    @sp4ghet
    Interesting
    Thieme Hennis
    @hennis_twitter
    hi guys, another question - how did you calibrate the CO2 sensor? Or was it pre-calibrated?
    Rikuo Hasegawa
    @sp4ghet
    My understanding is that it comes pre-calibrated and there's a way to auto recalibrate it from software without any mechanical steps needed (MH-Z16)
    Thieme Hennis
    @hennis_twitter
    do you know the difference with the Z19?
    Connor
    @kanr
    I didn’t see a zh19 on sandbox-electronics site but I imagine the zh19 is a slightly different ppm range. If you can provide a link to a zh19 I would be happy to check further.
    It has a different form factor but I haven't tried using it yet
    Thieme Hennis
    @hennis_twitter
    hi all, just had a discussion with an electronics company in the Netherlands. And they asked us whether or not the placement of sensors matters - e.g. the CO2 sensor
    Thieme Hennis
    @hennis_twitter
    so if you place the CO2 sensor on top or in the middle, or in the bottom.
    WebbPeter
    @WebbPeter
    @hennis_twitter This all depends on if you have good airflow or not. I would argue that yes it does matter that Co2 is heavier than air. That being said, placing it towards the middle is probably your best bet as well as just maximizing your air circulation. A forum thread about Co2 actuation would be a great add to the forums, I'd like to discuss this further as we're planning to add Co2 actuation to our V2.
    Thieme Hennis
    @hennis_twitter
    yes, thanks. I discussed this yesterday with our product designer - where to place the AstroPlant brain (which in fact is somewhat different from the OpenAg brain)? I've also asked our plant scientist from Wageningen. In the end we'll just probably test it using various sensors in and outside the kit and if airflow is insufficient, we'll need to add an extra internal fan.
    Thieme Hennis
    @hennis_twitter
    here a sneak preview of the outer casing - https://www.meetup.com/Border-Labs/photos/28229812/
    but lots of developments regarding electronics en software as well
    working hard to open source it all
    Thieme Hennis
    @hennis_twitter
    (PS. I'm not trying to spam here, just to give some insight into our developments and designs)
    Rikuo Hasegawa
    @sp4ghet
    woah, you changed the form factor a bit :)
    WebbPeter
    @WebbPeter
    I like it - very interested to see how it turns out.
    amol-c
    @amol-c
    We have land in india, but it doesn't have constant source of water nor electricity. So, the container farming will kinda solve the problem if we can get the cost down and power it with solar panels. Very excited for your work !
    David
    @davoclavo

    Hello! we've got the latest PFC build running and we are noticing that the Arduino's serial connection is getting restarted pretty frequently. From our research it could be due to power spikes, or perhaps a memory leak in the arduino sketch.

    The arduino handler is reconnecting properly every time it fails, but it has become a very frequent problem and it might be causing some noise in our sensor readings, cascading into a bunch of problems like the ph pumps dosing stuff when they shouldn't. We will increase the smoothing factor of the sensor readings to temporarily address this problem.

    Is anyone experiencing this issue as well? If so, what kind of things have you done to address the problem?

    image.png

    Here you can see how the pH measurements are reading a completely off value (4.99 vs the 7.13 average). By the way, prior to these visible spikes we disconnected the pH up/down solutions because the system ended up pouring the whole bottles into the mix causing a very gnarly outcome, so the pH is actually not changing at all due to controller, but it is being mis-read due to some sensor/arduino temporary error.

    David
    @davoclavo
    the arduino_handler seems to be failing in this line:
    https://github.com/davoclavo/openag_brain/blob/master/nodes/arduino_handler.py#L427
    if empty_read_count > MAX_EMPTY_READS:
      empty_read_count = 0
      raise Exception("arduino_handler: serial_connection.readline() broken")