Hi there! I am in search of a low-cost, standalone (self-powered) sensor pack to measure and store data for pH, DO, conductivity, salinity, turbidity, or any of the above. Anyone?
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I don’t have an answer for you, but I am interested to hear if anyone does.
Low-cost and standalone sensor ? 
The Clam/Mussel Toxicity Sensor …
This may make you smile but it has been tested in real conditions !
What you are looking for is a CTD sensor :
A slightly less analog, clam-orous or clam-azing solution but very likely more effective than the clam based toxicity sensor :
Have a look about their products. It’s interesting!
Thanks for the info! That CTD sensor looks similar to the one I found at Atlas Scientific:
They also have pH and dissolved oxygen sensors.
That mussel sensor looks cool!
@kurt_bluerobotics as I am sure you have discovered, the “low-cost” aspect scales very differently when you start looking at commercially available full sensor packages, depending on the accuracy and precision levels that you are needing.
It sounds like you are looking for a multiparameter sonde.
One open-source option that you can look into, for the sensors that you have already found is OpenCTD.
As far as commercial units go, the lowest price that I have found are Eureka Water Probes’ Manta+ , though they are still on the order of thousands of dollars.
My preferred, comparable option, would be the In-Situ Aqua Troll. I have found them to be a more reliable system with a great, intuitive UI.
If money is no object (though I know it always is) you can step up to systems from AML and RBR.
https://amloceanographic.com/
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Hey Ryan, thanks for all that information – very helpful. I’m especially interested in the OpenCTD solution!
Hi there. I am new to the USV world but attended the Blue Robotics blueTIDES Emerald City event in Seattle on May 25. I became very interested in trying to deploy my OpenCTD (mentioned above, and works great) from a BlueBoat (which I might be able to get access to). We are presently trying to deploy the OpenCTD from kayaks to monitor kelp beds. Simpler is better. To my way of thinking, something as simple as an electric fishing reel that will take the OpenCTD up and down every once in a while (or at planned stations on a mission) would be “fancy enough”. Has anyone had experience doing something like this? Thanks!
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Hi @bmbebout !
Our R&D team actually made a prototype winch for the BlueBoat, that raised and lowered a WiFi/Battery equipped Temperature and Depth sensor! We hope to offer a winch as a product someday…
I’ve also had success in the past using an electric fishing reel to raise and lower a commercial sonde with bluetooth - this is quite expensive, but lightweight and with a level wind…
Controlling either approach is easy - both use the same style ESCs that the brushless motors and thrusters already use, so controlling speed and direction is easy. Limit switches to count rotations of the reel, and detect a metal ball indicating the payload is retracted are also easy to read with the Navigator! Lua script control of peripherals should be an easy method for getting things like this all working together.
If you pursue this please continue to share your thoughts, learnings, and progress here!
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Jumpin’ in here -
I’m trying to find something that the drone community has utilized - similar flight controllers, send a PWM signal for raise/lower, and then power it using the BlueBoat’s internal board. And then the raise/lower could also be triggered using QGC waypoints likely.
Initial findings
Reefs RC and Daiwa Winch may offer a solution here. @bmbebout maybe you can chase these down and contact the vendors to see?
-Phil
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So here’s a low cost sensor kit that was designed by a high school student for the Santa Cruz County Science Fair competition last year, and then this year we made it submersible by putting it in a BR enclosure and using SealCon cable glands to seal the sensor probes.
This kit supports two Atlas Scientific probes and currently tests pH and ORP (oxidation reduction potential). But you could easily switch them to EC (electrical conductivity) or DO (dissolved oxygen) probes.
This kit is integrated with BlueOS on the BlueROV2 using Node-RED. We created a Json string in the Arduino project that outputs to the serial USB port and is connected to the BlueROV2’s RPi4 for real-time data display and logging. Node-RED also has a dashboard function that displays the data in graphical format!
Here’s the link to the build document I’m working on. Any feedback would be appreciated!
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Nice @kurt_bluerobotics - thanks for sharing! 
Once your guide is complete I’m happy to help you turn it into a forum post if you want it to be shared here more directly. That likely makes sense if you want a place for more detailed discussion about that specific kit / setup, since this thread has a broader focus on all kinds of low cost sensors
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I’m not sure what “complete” looks like. Would you mind reviewing it for me and let me know if you have any suggestions?
@bmbebout I think you might be interested in this!