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U.S. Cellular EnviroDIY LTE Bee connection

Home Forums Mayfly Data Logger U.S. Cellular EnviroDIY LTE Bee connection


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    • #17582
      Laura DeCicco


        • Mayfly v.1.1 (via the EnviroDIY Mayfly Data Logger Board and Starter Kit)
        • EnviroDIY LTE Bee
        • U.S. Cellular SIM card

        I’m using this sketch:

        I’m pretty confident I have changed the following code correctly: APN connection name (line 109) changed to the US Cellular name, and rearranging the variableList, updating the UUID as described in all the tutorials.

        When I push the code to the board I get:

        11:20:33.383 -> Waking modem and setting Cellular Carrier Options…
        11:20:38.909 -> Attempting to connect to the internet and synchronize RTC with NIST
        11:20:38.909 -> This may take up to two minutes!
        11:22:39.922 -> Could not connect to internet for clock sync.
        11:22:39.922 -> Putting modem to sleep


        I’ve been looking at these conversations for inspiration:

        Cannot connect to internet for clock sync with NIST

        Using Xbee Cellular Modem with ThingSpeak

        When the sketch is uploaded, I see the green and orange lights come on. The EnviorDIY board has a solid red light, and flashing tiny blue light. Once the message comes up  “Putting modem to sleep”, then the flashing blue light and the solid red light turns off.

        My 2 suspicions based on the other forum conversations are the modem settings need some adjustments since it’s US Cellular, or the modem just needs to stay on longer before going to sleep. Many of the older conversations link to code snippets that have been moved or are using the Digi modems (which I assume have different commands).

        Any suggestions are greatly appreciated, thanks!






      • #17583
        Laura DeCicco

          We can see some data usage from the SIM card…so it maybe it just needs a longer time before “Putting modem to sleep”?

        • #17584
          Shannon Hicks

            What is the APN name that US Cellular gave you use?  Is the SIM card activated?  Have you ever used that particular SIM card on another cellular device, like a tablet or phone?  Are you sure that there is sufficient US Cellular coverage in the area where you’re using the board?  They don’t actually own any cell networks, they just piggy-back off other carriers service like AT&T and Verizon.  And apparently Verizon doesn’t recognize the EnviroDIY SIM7080 as an allowed device on their network, so even if all of the other steps I’ve mentioned are okay regarding the APN and SIM card activation, if there’s only Verizon service in the area you’re trying to use the board, then it may not work.  Do you know what cell providers have coverage in your area?

          • #17585
            Laura DeCicco

              The APN  for US Cellular is “uscc05836.enterprise3.usc-cdp”. Southern WI is one of the few places US Cellular has dedicated towers and the signal is good (from what I’ve been told)….but if somehow the Verizon tower is what’s being hit that would make sense. I’ll try ordering a Hologram card to jump start this project (I don’t think that’s a long term solution due to contracting). I’ll also ask around to see if I can find a tablet/phone I could check the SIM card on, I hadn’t thought of that.

              Would Verizon not recognizing the board be consistent with what I’m seeing now is:
              “Could not wake modem for clock sync.”

              (slightly different than the original message ” Could not connect to internet for clock sync.”

              Thanks so much for the speedy response!

            • #17586
              Shannon Hicks

                If the Mayfly reports “could not wake modem for clock sync” then that means there’s no communication between the Mayfly and the cellular module.  That usually happens when then cell module isn’t properly seated all the way in the Bee socket or the pins aren’t aligned properly.  If the bee module is correctly installed, the clock sync part of the sketch is purposely made long (2 minutes) to give a newly activated SIM card time to join the network for the first time.  I don’t know how US Cellular is, but with our Hologram cards, it can sometimes take several tries of doing the 2-minute sync session to get the card to join the network for the first time.  Once it’s done that, subsequent connections can happen in about 5 seconds.  So if you’re in an area with weak or no US Cellular signal, then it might be challenging to get that initial connection completed.  If your cell data plan supports things like tablets or phones, then you could put the new SIM card in a different device that is constantly on and use that to establish the card with your provider first, and then move it back to the SIM7080 after that.  And if US Cellular doesn’t recognize the SIM7080 as an approved device for their network (which is what Verizon does), then it probably won’t let the Mayfly connect at all.  That why we’ve been using the Hologram network for the past 6 years because they’ve supported all of the various cell modules we’ve ever tried to use, and for around $5 per month per device.

                What antenna are you using?  There’s 2 small antennas that come with the SIM7080 board (one’s for cell, the other for GPS and not currently used), but we’ve found that the small cell antenna is usually not sufficient unless you’re in an urban area or very near a supported cell tower.  We’ve had much better luck with a larger antenna like the one suggested in section 6.1 of the manual:  https://www.envirodiy.org/knowledge-base/building-an-envirodiy-monitoring-station/

              • #17587
                Laura DeCicco

                  You’re right! I had pulled the SIM card out to get the ID and apparently didn’t quite push it in far enough, so I’m back to the “Could not connect to internet for clock sync.”.

                  The antenna is that little green one (I don’t see a part number/name but I assume you know what I mean). I’ll look into getting the bigger one.


                  While I wait on the Hologram card, I’ll keep restarting the Serial Monitor (which wakes up the modem and tries to connect again), maybe it’ll catch eventually. Would it be helpful to add a delay somewhere in the code so it’s longer than 2 minutes?







                • #17590
                  Shannon Hicks

                    There’s no easy way to tell your Mayfly sketch to  wait longer on initial startup, the instructions for that are buried deep in one of the supporting library files and not in the main sketch.  Usually just having the larger antenna and using it in an area with known strong cell signals during the initial activation is all that’s necessary.

                    One other thing to check is that you’ve inserted the SIM card properly in the cell module.  The first photo in section 6.1 of the manual shows the right way to insert the card.  There’s a little notch in one corner of the card, and that’s the end you insert first, and with the gold contacts of the card facing the green circuit board and the text on the card facing away from the circuit board, as shown in the photo.  Sometimes people accidentally insert the card upside down or backwards (or both upside down AND backwards), which obviously will prevent the board from making a connection.  We’ve also seen antennas not properly snapped all the way onto the tiny little antenna jack, resulting in connection issues.  So just make sure everything looks the photos shown in the manual.

                  • #17594
                    Laura DeCicco

                      Much like some of the other issues with similar initial connection problems….I re-started the Serial Monitor enough times that it eventually worked! For the record, U.S. Cellular no longer piggy backs off Verizon, so we’re not concerned that we might accidently float into a Verizon tower.


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