Tuesday, 25 February 2025

MEGAphone SIM Card / SD Card Module

 In the previous post I designed the cellular modem module.  However, the requirements for the device include having a SIM card, which I had elected to put on a separate module, so it's time to make that module now:

Requirement 2.2.1: Cellular Module Carrier board that can accept an industry standard industrial cellular modem, breaking out all pins from the connectors, and provides a SIM card slot.

It shouldn't be hard to do.

It'll be an edge-mounted module, which won't be a problem since I added support for edge-mounted modules into my procedural footprint generator.

I also know the single part that needs to go on the module, i.e., the combined SIM and SD card slot.  When I made the last prototypes I couldn't buy them singly, so ended up buying a whole reel of 1,200 pieces -- and I still have 1,194 of them left, so that's what I'm going to use! But if others can't source the same part, then they can design a module that takes a different part -- that's part of the benefit of this modularisation approach!

The parts I have are Molex 104168-1616's. Unfortunately SnapEDA doesn't have a model for it.  Mouser does have a 3D model for it, but no footprint or symbol. I have a vague recollection that I made a footprint for it at some point, but I don't remember for sure, or where I would have put it.

The datasheet doesn't have the drawing, but I did find the drawing elsewhere:


Okay, I have created a PCB symbol and footprint now. The footprint I have verified against the 3D model to make sure that everything lines up, which it does:

So let's lay it out now, with the 8 pins for SD card and 8 for SIM card, and GND. So that's 17 pins, plus we'll have a dummy for power. So this is what the result looks like:



Now to pop that into the PCBWay order, if I'm not already too late.

So that closes out this requirement:

Requirement 2.2.1: Cellular Module Carrier board that can accept an industry standard industrial cellular modem, breaking out all pins from the connectors, and provides a SIM card slot.

As usual the source is in the modules/ directory of https://github.com/gardners/megaphone-r5-modular 

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