pH and DO sensors

Hardware, PWM, and Optics
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Are there any plans to add pH and DO sensors?

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Hi @Dandor,

We don’t have plans to add them soon, but I’ll add this as a feature request to our roadmap. The tricky part is space: Submerged DO and pH sensors are big. However, there was recent technologies that use optical systems for DO and pH that may work well.

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3

Hi, How about now? Are there any plans to add pH and DO sensors?

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Hi @bob.zha, it’s on our product roadmap, but nothing to share yet!

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And now? :slight_smile: Even just having DO sensor that could control agitation and air bubbler would make a huge difference!

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Actually I do have a small update, I’ll share this week.

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@CamDavidsonPilon we’re all waiting to hear the update :slight_smile:

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We did this a few weeks ago, and we haven’t had a minute to progress it unfortunately. But here’s the set up:

pH set up

Assembly looks like:

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1 (8)480Ă—640 116 KB

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3 (1)480Ă—640 75.4 KB

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2 (3)480Ă—640 92.9 KB

You need to change the pH circuit to i2c mode: page 37 here.

Once attached to your Raspberry Pi, you should be able to “ping” the pH circuit with:

i2cdetect -y 1

and look for a signal at 0x63.

Then you can use the code here: [wip] Integrating pH / DO probes (software only) · Issue #483 · Pioreactor/pioreactor · GitHub

as a start for developing a plugin / job.

You still need to calibrate the cirruit, and those instructions can be found in the docs for the pH circuit.

For DO, there exist equivalent proles and circuits.

9

For everyone looking to add more sensors, I’m wondering how you manage to fit them into your 20ml vials? We’re setting up a meeting for the various people working on larger Pioreactors - at Applicability of pioreactor hardware/software for larger bioreactor setups?

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@CamDavidsonPilon This setup looks really interesting! We might implement it on our pioreactors. Do you have an update on this setup? Thanks in advance :slight_smile:

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Hey, new to the forum.

Just wondering why the thought process isn’t to include a flowcell that utilises the peristaltic pump control to run a separate 2-5mL vessel. Intergration would only require the designation of a cap+oring and/or a compression fitting similar to the electrode storage cap that comes with any probe. Alternatively, why not replicate something similar to the Hamilton Flowcell XL if end users want integrated pH and DO? I don’t have a great deal of experience with the units, but many water treatment facilities use low-cost units. I believe the price could be kept very low, and the internal volume for a well-designed unit should be <10ml when also displaced by a probe.

Edit: actually, the more i think about this, the easier i think it might be to adjust your cap with ports to include an oring fitting and two open ports, simply recirculate the media through the two glass vials and you’ll get an online pH/do reading.

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Hi Cam,

are there any pitfalls to avoid when implementing this?

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Probably, but I haven’t dug deep enough to encounter them! I think the hardest part is going to be calibration via Atlas’ equipment.

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Hi there! I use the I3 Interlink Board, witch allows you to download the Atlas IoT Monitoring system in a RBpi4. What I do is the calibrations thought their UI and then they are automatically saved in the volatile memory of the EZO system, witch you can then unplug from the RBPI and connect into the Pio like a Hat (Thats what the people from Atlas told me). My issue comes when I try to display the pH values into the UI… but that is just me and my useless relationship with coding… If anybody could develop a Plugin for it would be amazing!!!

(I hope this info helps @johannes)

Happy Thursday!

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Hi Curro,
we also use the i3 interlink board. We recently bought this pH probe

It has 4.3 mm diameter. It is quite expensive (230€) but probes with smaller diameter (3mm) are much more expensive and very fragile!

I wrote a simple script for calibration using the CLI (no fancy plugin). If you are interested, I can share the code.

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You mention that there exists an equivalent set up for DO. Do you happen to have any specific recommendations?