U.S. Cellular EnviroDIY LTE Bee connection

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?

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/

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.