I am currently attempting to design a small custom PCB based IoT business cards that communicate over a cellular network for the purpose of impressing employers. Since I will literally be giving these away, price is absolutely critical for my design.

Each card will be sending extremely small amounts of data (less than a kilobyte) over the course of their lifetime so fast transfer speeds are a non issue. Because of this, I was hoping to utilize old Sim900 modules since they are around $8 a piece.

Unfortunately, most 2G networks in the United States have already or are going to shut down very soon. While pricing for access to newer 4G networks isn't a huge deal, the cost of the hardware to utilize them is. It seems that 4G modules cost at a minimum $30 in the amounts that I will be purchasing them. This is about 3 times what I'm willing to pay for my use case.

Are there any 2G networks specifically for IoT devices still around or have most of them shut down at this point? Alternatively, if there is some other technology that I could use to get these cards internet access, I am open to possibly implementing them.

  • Maybe if you told us what sort of data you are planning on sending and in what direction (to or from the device mostly?). Also where are they likely to be used, city centres or rural? – hardillb Jul 14 at 16:28
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    I'd be curious to understand what usage you demonstrate to the recipient since they can't see the data being sent. One option could be to use LoRaWAN, but TTN coverage in the US is spotty. Maybe using the Helium network? Still, with a PCB antenna indoor coverage will probably be quite limited. – jcaron Jul 16 at 11:55
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    Found this, though the mention of both GPRS and NB-IoT worries me. Also this. This is probably more trustworthy. EOL, but a pointer towards chip providers maybe... – jcaron Jul 16 at 11:59
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    Also this. Note that you would need to check band support for compatibility with the network(s) you pick. – jcaron Jul 16 at 12:03
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    Thank you jcaron! This is exactly what I was looking for. I have considered using LoRaWAN, but so far I have found that the only cities that have these networks are large coastal cities (Most of my work will be done in midwest cities). The data will be sent to my website where the recipient could see it to prove it actually sent. Regarding the concern of it tracking you our listening in; these will be completely exposed PCBs so any engineer (my target demographic for these cards) with any electrical experience will be able to easily identify basic components, like a microphone, on the board. – acp_ Jul 16 at 17:28

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