First of all Thanks a ton for replying in details. You got my problem and scenario so well.. Thanks againHeater wrote: ↑Sat Aug 11, 2018 1:27 pmI have a bunch of devices, including Pi, that are in remote locations and communicate with servers in google cloud via 3G or 4G. Both in the USA and in Europe.
In most cases the Pi or other device connects to a cellular modem or dongle using WiFi.
In general these systems have worked well. However one will always get occasional disconnects and connection failures of the cellular network.
In the USA they like to put data caps on everything so every month we get informed that we have used our limit for the month and data rate will be throttled to 200K bytes per second. That's OK our devices are only streaming at 100KBs.
If your Pi are at remote locations were it is hard or expensive to visit and fix them be sure to take some precautions to ensure reliability...
Use the hardware watchdog on the Pi to reboot the thing in case of an OS crash or other catastrophe.
Make your root file system read only so as to avoid file system corruption and failure to reboot after power interruptions.
Think about arranging that the cellular modem can be power cycled. Some times they get stuck and that is all one can do.
Thank you for the post, I got that too but it is not fitting in my requirement as 1) it is expensive (as I expect to use many Pis) and 2) I want to create something (if possible).fruitoftheloom wrote: ↑Sat Aug 11, 2018 11:11 am
Different countries have different standards, but a HAT may suffice:
I cannot imagine there is any useful way to connect a SIM card to a Pi.1) I will try USB dongle. Do you think there is any custom made board to connect SIM card to Pi?
The Pi has built in watchdog hardware. Use the watchdog package with it. Google it.2) Any suggestions for hardware watchdog?