Adding a SIM card holder: On PCB vs. separate (data logger)

[Martin F]

Hi all,

We're developing a data logger with SD card and WiFi capability.
Currently, this logger is able to connect to a WiFi hotspot, incl. e.g. a mobile phone or mobile 4G WiFi hotspot.

Going forward, we'd like to offer a cellular option as part of the logger (which is used globally).

We've considered three options:

1) Build in a SIM card holder and functionality directly in the logger
- Probably the most elegant solution, but we're unsure of the complexity involved and the cost

2) Build a small module/device that functions as a mobile hotspot and power it via the same cable as the logger
- Advantage is that users can buy it as a module only if they need it, hence beneficial if it's costly to add; however, less elegant than 1) as it'll create more clutter
- Also unsure how difficult it is to build this device as a module from scratch and whether some good starting points exist

3) Purchase a batch of premade mobile unlocked cellular hotspots (e.g. USB sticks) and power this via the same cable as the logger
- Simplest and fastest-to-market, but also assume these are the most costly solution

Any advice/tips on what you think would be ideal and what we should consider in this?
If you have any specific suggestions for components/hardware that we should consider, we'd be happy to learn as well!

Thanks a ton,
Martin