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Reply To: Turbidity Sensor Information/Questions

Home Forums Environmental Sensors Turbidity Sensor Information/Questions Reply To: Turbidity Sensor Information/Questions

Shannon Hicks

    There’s a few things in your post to clarify to make sure we’re talking about the same equipment.  The various instructional videos and manuals we’ve released in the past few years cover several different configurations of sensors and cables and equipment.  The majority of the stations we deployed before 2020 had a Meter Group CTD sensor and a Campbell Scientific OBS3+ turbidity sensor on them.  We also used to sell Monitoring Station Kits that contained Pelican 1120 cases that were pre-drilled and tapped for 3 cable glands:  one for solar panel cable, one for CTD sensor, and one for OBS3+ turbidity sensor.  The CTD and old turbidity sensors had cables that required the same diameter cable glands, so we used the 69915K53 size (0.24″-0.47″ cables and 1/2″ NPT threads).

    Campbell Scientific discontinued the OBS3+ turbidity sensor a few years ago and since there was not a ready replacement, we stopped including the cable gland and pre-drilling the holes in the Pelican cases that we sold, since most people were just building CTD-only stations.

    A few months ago, Campbell Scientific released the ClariVUE10 turbidity sensor, and it has a cable with a smaller diameter.  Therefore we recommend using a 69915K54 cable gland (0.2″-0.35″ range, 1/2″ NPT) for the ClariVUE10 turbidity sensor cable.

    The Meter Group Hydros21 sensor can be purchased with either bare wire leads on the end of the cable, or a 3.5mm stereo headphone plug.  We usually tell users to choose the stereo plug because it’s the easiest to use, and we developed a Grove-to-3.5mm-jack adapter board many years ago for connecting the stereo plug to the Grove jack of the EnviroDIY Mayfly.  The ClariVUE turbidity sensor cable has bare wires on the end, there is no connecter on the cable. We developed the multipurpose 6-pin screw terminal board for using bare wire sensors like the ClariVUE with the Mayfly.  You could also use that same screw terminal board for connecting a Hydros21 CTD sensor to the Mayfly if you bought the sensor with bare wires instead of the headphone jack.  It’s worth noting however that we may need to develop a new screw terminal board with some additional circuitry on it to properly communicate with some SDI-12 sensors like the ClariVUE10, so we’re still working on this, which is why we haven’t published official instructions on how to connect a ClariVUE10 to the Mayfly yet.

    The term “Molex connectors” refers to a wide variety of sizes and types of connectors so I’m not sure to which ones you’re referring, but  there aren’t any Molex connectors anywhere on the EnviroDIY Mayfly, and we don’t use them in any of our recommended instructions.  Are you referring to the Grove cables and Grove jacks (the six or seven white, 4-pin polarized sockets on the Mayfly)?  All you should need to connect a ClariVUE10 to the Mayfly is the screw terminal board mentioned above, and a short double-ended Grove cable, like the ones we include in the Starter Kit or the Monitoring Station Kit, or that can be found from various sellers on Amazon.

    Another thing to note, the ClariVUE10 sensors require 9.6v to 18v DC to operate.  The previous EnviroDIY Mayfly boards we sold prior to the fall of 2021 were not capable of powering these sensors.  The Mayfly v1.0 we released in October and the new v1.1 board releasing next week are able to generate a 12v power source capable of powering the sensor, but you have to move the small jumper next to the Grove jack to change the voltage level sent to that jack to match whatever sensor you’re connecting (your options are 3.3v, 5v, and 12v).  So instruction for all these steps are being finalized now, along with writing and testing new code examples for all the major configurations we recommend, which will include the ClariVUE10.

    As for the anti-fouling tape, it’s probably not necessary.  The ClariVUE10 is manufactured with a copper end-plate, so algal growth right around the sensor window should probably be reduced, however the sapphire windows themselves will need to be cleaned regularly, plus we find that the majority of fouling issued to our turbidity sensors is cause by large debris like leaves, sticks, mud, rocks, etc, which is why still suggest frequent service visits to the station, especially for stations that don’t transmit their data to an online portal like Monitor My Watershed.