[Shannon Hicks]

That’s a good question, and something that I’m sure a few other people have accidentally done before, me included.  Luckily the charger chip and the Mayfly v1.0 and v1.1 board should not be affected by having a solar panel connected with the wires reversed.  I just did a test here with a Mayfly v1.0 and a v1.1, where I first connected a panel with the correct orientation.  The battery was charging fine and the board performed properly.  Then I connected the panel with the wrong polarity.  The battery did not charge, but the Mayfly continued to work fine, because the battery was supplying all the operating voltage.  Once I reconnected the panel with the right polarity, the battery started charging again at the same rate.  So the charger chip or any of the other components on the board did not appear to be damaged during my test.  But depending on what battery situation you’ve got or solar panel size, or Mayfly version, things may have been damaged.  But if you station is operating properly after correcting the polarity issue and the battery is charging like normal, then I think you should be okay.

[Shannon Hicks]

I’m not familiar with the new C model, but I did use the older, now-discontinued one awhile back.  Without digging into the manual and the library too deep, I’m guessing it might be an I2C address issue?  The old model used 0xB8 whereas the new one uses 0x38.  So go into the ModularSensors/src/sensors folder and edit AOSongAM2315.cpp, find line 34 and change the address from 0xB8 to 0x38.

[Shannon Hicks]

That’s not much current, so most relay boards should be able to handle that with no problem.  I think that latching Grove board (https://www.seeedstudio.com/Grove-2-Coil-Latching-Relay.html) would probably work good for your situation so your Mayfly board could activate the relay 15 minutes before you want to sample, and then go back to sleep and it won’t have to hold a pin high to keep the relay closed.  You can connect the relay board to the Mayfly via one of the unused Grove jacks (but make sure you set the voltage selection jumper next to that Grove jack to 5v since the relay board operates at 5v).  I’m sure there are other latching relay boards out there that would work as well, but the Grove jack makes wiring it up convenient.

[Shannon Hicks]

What’s the current draw of your heaters?  There’s a variety of relays you could use, but I know several people have had good luck with various Grove-compatible relay boards, like the ones from Seeed.  But your options are going to depend on how many amps of current the heater draws from the battery.

[Shannon Hicks]

Have you tried a different microSD card?  Either it’s a defective card or sometimes one or more of the pins in the microSD card socket can get damaged when inserting a card and cause a short-circuit inside the socket that prevents the Mayfly from operating properly.  Are you using the onboard microSD socket on the Mayfly board, or the optional vertical microSD card board plugged into the 2×4 header next to the power switch?

[Shannon Hicks]

Sensor values of -9999 for the Hyrdos21 CTD sensor mean that the Mayfly board isn’t hearing any communication from the sensor.  Did you carefully follow all the directions in the Monitoring Station Manual (specifically section 6) for preparing and programming a Mayfly for use with the Hydros21?  The sensor’s default SDI12 channel number needs to be changed from 0 to 1 (if you’re using one of our example ModularSensor sketches), and it must be connected securely to the 3.5mm headphone jack and connected to one of the Grove jacks labeled SDI-12.  If you’re using a bare-wire CTD sensor, then doublecheck that you’ve got the appropriately-colored wires connected to the right terminals of the screw terminal adapter board (for power, data, and ground).

And the OBS-3 turbidity sensor doesn’t appear to be connected either, because with no sensor connected the low range value is usually around 60NTU and the high range is around 250NTU.  The online Monitoring Station Manual doesn’t show instructions for how to connect an OBS-3 sensor anymore because they were discontinued 4 years ago.  You’ll need either our old-style 6-terminal screw adapter board, or our newer multipurpose 6-terminal adapter board.  That board gets connected to the Mayfly via the AA0-AA1 aux analog Grove jack.  The wiring colors on the OBS-3 cable should be green, black, and shield all connected to ground.  Red connected to 5V (be sure to move the voltage-selection jumper next to the Aux Analog Grove jacks to the 5v position (it ships in the default 3v position).  The blue wires goes to D1 (or S1), and the white wire goes to D2 (or S2).  If you’re using the newer multipurpose screw terminal adapter board, be sure the 3 solder jumpers on the back of the adapter board are soldered in the DEFAULT position (as shown in on of the product photos on the shop page for the adapter:  https://www.envirodiy.org/product/envirodiy-grove-6-pin-screw-terminal-adapter-pack-of-5/)

[Shannon Hicks]

The UUIDs for the various parameters are generated by the MonitorMyWatershed website.  When you created the site for your particular station, you had to manually add whatever parameters you were interested in receiving from the Mayfly logger.  It looks like you added the 3 parameters for the Hydros21 and one turbidity parameter for the OBS3 sensor.  The old OBS3 turbidity sensors have two analog outputs, one low range and one high range (there’s more about this in the Monitoring Station Manual).  So you’ll need to log in to MonitorMyWatershed, go to your station details, then hit the Manage Sensors button and then add the additional parameters, starting with another OBS3 turbidity value.  Then you’ll need to add the parameters from the Mayfly itself, which are battery voltage, ds3231 temperature (Mayfly board temp that’s sometimes helpful for diagnostics), and the EnviroDIY LTEbee sim7080 signal percent.  All 3 of those parameters can be found on MMW dropdown menu under the sensor manufacturer name of EnviroDIY.

[Shannon Hicks]

Did you download the libraries.zip file correctly from this page carefully following the instructions in the Readme:  https://github.com/EnviroDIY/Libraries

and then confirm that all 42 folders are in your Arduino/libraries folder (not nested into a sub-folder called “Arduino/libraries/libraries”) and that the folders contain actual files are are not empty?  You also have to restart the Arduino IDE if you unzip the files into the Libraries folder while the IDE is running.

[Shannon Hicks]

The example code for a CTD/OBS3/SIM7080 station can be found here:  https://github.com/EnviroDIY/ModularSensors/tree/master/examples/DRWI_SIM7080LTE

The only changes you’ll have to make is to enter the turbidity sensor calibration information in the correct place (lines 157 to 186), give the logger a unique name in line 59, and enter your UUID from MonitorMyWatershed in the section lines 220-238 (making sure that the order of the parameters in the UUIDs match the order of the variables in lines 194-201).  If your UUIDs from the website are in a different order than the code, then rearrange the variables in lines 194-201 to match the order of the UUIDs.  DO NOT rearrange the order of the UUIDs in lines 194-201.

If you’re using a provider other than Hologram, you’ll need to change the APN as listed in line 106.  And make sure the SDI12 channel of your CTD sensor has been change to something other than ‘0’ (we usually use ‘1’ which is why it’s set to 1 in line 146.)  And make sure the jumper next to the Aux Analog Grove Jacks is set to 5v (the middle position) in order to power the analog OBS3 sensors with the appropriate 5v excitation voltage.

[Shannon Hicks]

It’s likely that you deleted something important and that’s why the code isn’t working properly.  What sensors are you trying to use with your logger?

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