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The mayfly can generate a square wave which can then be filtered/rounded to a sinish wave. It would still need to be amplified with a low current op-amp

For TDS trials I personally would start with something like this, though might need more research – it has methods of calibration. The qu is just what sort of value does the results…[Read more]

Now it’s the asynchronous open that’s causing trouble. That *should* be blocking. The program should not continue until the URC arrives. I will need to test that more.

Anyway, another change in TinyGSM:

    // Use an asynchronous open to reduce the number of terminal freeze-ups
    // This is still blocking until the URC arrives
    // The…

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Wow, thanks a lot for the literature, and also for the new resources. Public Lab seems to have some really good stuff and I will for sure be lurking around there.

I see that DC voltage is not recommended for use in conductivity measurements for electrochemical reasons, as well as 5v is high and is not required for successful conductivity…[Read more]

ModularSensors does NOT work using an ESP8266 of any flavor, including NodeMCU, as the main processor.

The Yosemitech library might; I’ve never tried.

Yeah im sorry was really tired but its working now. Do you or someone know if there is a library for the nodemcu?

Sara, this is really amazing support. Thank you very much for your contributions to the community.

Unfortunately, problems persist. As far as I can tell, switching to synchronous close did not improve the situation. I’m attaching another log, this time with TINY_GSM_DEBUG enabled. We are still sometimes getting +CME ERROR: Operation not allowed…[Read more]

Also
https://publiclab.org/wiki/conductivity_sensing
which has
https://publiclab.org/notes/bhickman/05-09-2016/conductivity-and-temperature-meter

Oh, and yes, the issue with NIST is really common. There have been a few GitHub issues about it. I’m trying to connect over TCP to the daytime server. That server is designed to respond to any incoming connection on port 37 with 4 bytes representing the current timestamp and immediately close the connection. A lot of the time the various…[Read more]

Cutting the rod in small diameter wasn’t a problem for me. Ideally it should be a square cut.
Ti oxidation layer protects it https://cdn.ymaws.com/titanium.org/resource/resmgr/2010_2014_papers/HouserRobert_2011.pdf

You may have two different sensors if you want to be able to do “water detection” v “conductance”
Also depends on power…[Read more]

It’s awesome that you’ve created your own publisher!

Ok. I see what’s happening. The R410M takes a *really* long time to close sockets (like 2 minutes). To speed things up, I call the socket close “asynchronously” – that is, tell it to close and move on. But what I think is happening here is that I’m telling the socket to close before opening…[Read more]

Thanks Sara. Some more info for you. First, the CGMR and GMR commands both result in the response ERROR, as you can see in the output below.

Additionally, it sometimes seems to struggle getting a connection to NIST, also as in the example below. It took two tries before it finally connected, and this seems to be commonb. Note also the funkiness…[Read more]

Doh. Yes, I thought of that as I was driving home. Do add the lines setting the wake pin high.

Do you know what version of the firmware you’re running? To check, you can either hook it up to the u-blox m-center on your computer, run a pass through sketch and send it the commands AT+CGMR? and AT+GMR?, or tack these lines in after the modem…[Read more]

Thank you Sara.

Inching closer. Prior to switching to the modemLast branch I tried something similar to what @acgold suggested. I added the following lines:

    if (modemVccPin >= 0)
    {
        pinMode(modemSleepRqPin, OUTPUT);
        digitalWrite(modemSleepRqPin, HIGH);
    }

to my file, just after greenredflash();. This allowed the…[Read more]

a. We saw no evidence that the sensor had any issue related to condensation during the tests given that there was a hydrophobic coating on the sensor face and that the bad data occurred at random temperatures as opposed to only when the temperatures were low.

That’s good to know. What was the fluoropolymer grease you used?

b. Reading out the…

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Hi neilh

Thanks a lot for your response.

Good idea with the titanium rod. How would you cut that?
Right now, I plan to use PVC to anchor the array to streambeds. I haven’t put the first one together yet, but I intend to use a coupler and end cap that will accommodate a cable gland big enough for my 5-conductor, 18awg cable. The housing for the…[Read more]

I look at the measurement accuracy, and vented depth sensors. Especially at lower water levels vented depth sensors are I believe the most accurate.
Good measurement accuracy starts at about 0.25% of range and optionally can be of 0.1%
I’ve been using the Keller Acculevel for ranges over 10′, and characterizing the Keller Nanolevel for ranges…[Read more]

Hi Charles,
I’ve used titanium rod – 1/16″ Dia 2′ $1.62 – https://www.mcmaster.com/89145k28
and its easy to crimp a wire to the rod. I might be able to find a picture of it at some point.
Its also possible to drill two holes through a PVC end cap, and then snuggly push the rod through with a watersealant adhesive on it – uses the friction fit…[Read more]

We just finished the last of a series of tests of the Maxbotix. With the changes which Sara suggested (close the serial port after each log interval and restart it for each new consectutive interval), the sleep code does work if the sensor is continuously powered.

Setup: Maxbotix 7389 sensor with the target either stream water or a fixed/flat…[Read more]

Yes, it’s probably related to the same issues that @acgold had. These ublox modules just seem to be so much more finicky than the 2G SIM800’s were.

Could you try switching to the “ModemLast” branch? That’s where the most recent work is and I’d prefer to do more of the troubleshooting on that branch since it’s mostly modifications to the setup…[Read more]