2019-04-16 at 8:47 AM #12878
I’m working with a watershed groups located in a watershed with intense CAFO activity. They are interested in monitoring DO continuously using the Mayfly EnviroDIY Monitoring Station. I was recommended the Zebra-Tech Optical DO sensor which costs nearly 3500. I’m sure this is a great sensor but is a little expensive for this group. Any recommendations on a quality DO sensor that will work with the Mayfly Logger board that is in the 1k-1.5k range?
2019-04-20 at 12:26 PM #12881
You might want to check out Atlas Scientific DO sensors (https://www.atlas-scientific.com/product_pages/kits/do_kit.html). They are galvanic probes that are cheap and fairly accurate (+- 0.05 mg/l), but they do require a fair bit of effort to piece together. You would need the DO kit (previous link, $280), an isolated carrier board ($40, https://www.atlas-scientific.com/product_pages/components/single_carrier_iso.html), and an extension cable where the connection to the probe needs to be waterproofed with CoaxSeal ($17,https://www.atlas-scientific.com/product_pages/components/bnc_10.html). You then would need to figure out how to connect the carrier board to the Mayfly. We are starting to use them for our project, and we’ve created our own carrier board to hold 3 sensor chips rather than use their carrier boards (https://github.com/acgold/Atlas-Scientific-Carrier-Board). They work with the ModularSensors library (in I2C mode), and the data sheets from Atlas Scientific are great (https://www.atlas-scientific.com/_files/_datasheets/_circuit/DO_EZO_Datasheet.pdf?)
2019-04-20 at 12:30 PM #12882
2019-04-23 at 10:47 PM #12883
I highly recommend the YosemiTech DO sensors, which use optical sensing technology for long-term stability. https://www.yosemitech.com/en/product-cat-11.html
They use Modbus communication and can be user-calibrated. Here are their two main models (the Y505 is new and not on their website).
Y504 (standard model):
~$650 each (plus shipping plus 25% new China import tax)
±1% DO accuracy
±0.2°C temp accuracy
5 m standard cable length (10 m at additional cost)
10 s response time
Y505 (low-cost, aquaculture model):
~$450 each (plus shipping plus 25% new China import tax)
±3% DO accuracy
±0.5°C temp accuracy
10 m standard cable length
40 s response time
no protection cap over sensor surface
There are a few minor drawbacks to YosemiTech. They require purchasing with a bank transfer rather than a credit card, and their documentation isn’t great. However, we’re trying to help them with the later by reposting manuals and other info at https://github.com/EnviroDIY/YosemitechModbus. Overall, however, I find their sensors to be of excellent quality, and their email response time to questions (and also a warranty repair) have been quite good.
2019-04-23 at 11:01 PM #12884
I forgot to mention that YosemiTech also makes a multi-parameter sonde with an optional wiper. http://www.yosemitech.com/en/product-20.html
This is an approach to having a wiper on the DO probe, as none of the stand-alone DO probes have a wiper (unlike Turbidity, Chlorophyl and Blue-Green Algal stand-alone sensors, which have models with built-in brushes).
Also, as with all YosemiTech sensors, you need to power the DO sensors with 6-12 V (5V only works if you have in-line capacitors and no brushes) and you need an RS485-to-TTL serial converter. See https://github.com/EnviroDIY/YosemitechModbus#suggested-setup-with-an-envirodiy-mayfly and https://github.com/EnviroDIY/SensorModbusMaster/tree/master/hardware/Modbus-Mayfly_WingShield for details on that.
2019-05-15 at 8:31 AM #12896
Thanks for the great info all!
If I were looking to add the Yosemitech standard model to a Mayfly Station with a CTD and Campbell Turbidity sensor would I need to enhance the power capability? Bigger battery…bigger panel? Do you have code for the Yosemitech? Are there other considerations I need to take into account?
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