Rugged Meshtastic node + USB power bank

I wanted a Meshtastic node that I could carry around in my backpack that would be as maintenance free as possible. This meant the case itself had to be rugged so I could throw around my backpack and not worry about the case cracking, and it meant it needed to have a long battery life so I don't have to charge it often. 

A rugged case, to me, means it has thick enough walls to take some abuse and a way to mount stuff inside so the internals are protected from impacts. The meshtastic and USB power bank boards are pretty tough with no large heavy components, so those can be hard mounted to the case. For the batteries though, I designed the internal cavity to fit the six 18650 cells (they're actually 18700 thanks to the built-in protection circuits) with a layer of foam around them. That way, they're a snug fit and the foam should reduce any impacts the case gets.

Since I wanted a long battery life and this didn't need to fit in my pocket, I went overkill with the batteries, making a pack with six 2200mAh 18650 cells, which should last about six to eight weeks with the radio on. Unfortunately, with the RAK19003's built-in charger, this would also take just under two days to charge, so I needed a faster charger. I figured I might as well get a power bank board for this, since they can have pretty fast charging and, well, why not make it able to charge other stuff too? I found the pretty basic HiLetgo 18W board with two USB-A outputs and a bidirectional USB-C PD port that fit nicely. This board means I can charge the pack in under three hours and can charge up to three devices at once (albeit not very fast). 

Lastly I needed a power switch to turn the radio off because making a battery powered device that can't turn off is just a terrible idea, even with protected batteries. I recessed the switch so that it can't [easily] be turned on or off accidentally while in my backpack. I would have liked to recess that SMA antenna connector as well, but it would have required significant rework so I left it as is, maybe at some point I'll go back and redo that part. Rather than mounting an antenna directly to the case, I have a coax cable running from inside my backpack to a Gizont whip antenna sewn into the arm strap. There's no good reason to do it this way, I just thought it'd be cool.

As far as printing the model goes, everything except the top prints without supports. The letters (0 and 1 inside the switch recess) are impossible to print unless you have special support material that works with no gap. I would recommend skipping the letters if you don't have such a material or a multi-material printer. Yes this was a lazy design choice, but you don't lose much by not having them there. 

To mount the RAK19003 board, you need three M2x6mm self tapping screws and to mount the USB power bank board, you need three M3x4mm self tapping screws (or cut some 8mm ones like I did). The rings on the ends that hold the two halves together simply press fit on, they're a tight fit to the point that I've had to print new ones every time I had to take it apart. There is a spot for a 3mm LED, which I intend to wire up as a message alert indicator once I figure out how to do that given the RAK19003's lack of GPIO pins.

As with all my other models, I don't think this is worth selling, but if you want to take my design and sell prints of it, go for it, just leave a link to this page somewhere in the listing.