USB-A-ugment: USB-A port card with internal dongle port and addons

Finally, I can show an ambitious Expansion Card of mine, that I’ve already been using personally. It’s the USB-A card on steroids - designed to be compatible with it, but it can do so much more!

For a start, there’s an internal USB-A socket for your mouse receiver - you don’t even have to take it apart or solder onto the board, a receiver can plug right in and you can unplug it whenever you want. There’s also a USB-C pulldown switch - you can power the card off whenever you need, using i.e. the Framework screwdriver spudger side. And, it doesn’t extend beyond the feet in the Z direction. That’s not all, however!

There’s also a grid of pins that you can use for addons. I’ve made three addons - MicroSD reader, USB-C 2.0 host port, and USB-UART + EC debug cards, which plug onto the pins and extend from beyond the laptop. They can be used as standalone cards if you solder a USB-C plug on, too! Furthermore, it’s easy to design your own addons - the expansion are on 2.54mm grid, so you can just use a protoboard and add your own stuff. The addon cards are designed to lighten up my collection of dongles, so they’re more temporary additions you can plug in and out whenever you need one and avoid taking up a whole USB-C port. I will take pictures of these when I get home - forgot.

Oh, and this board is made to fit inside the stock USB-A Expansion shell, which it barely doesn’t - but it does fit if you trim the board a little bit; next PCB version will fix this. So, if you solder a mouse receiver to this card instead of the internal USB-A socket, you can also use it this card as the PCB for the stock USB-A card + mouse receiver inside!

At the moment, I don’t have a 3D printed shell design - yet ^^ I will put up a bounty on these forums in an hour or two - whoever designs a shell from the 3D printed files I’ll provide, will get this card and a full set of addons! If nobody can do that within a week, I’ll do it myself, just need to get to my Solidworks PC. When I have the shell, I’ll add it to the store - in the meantime, I’ll ship this card with extra threaded inserts so that you can get a shell printed on your own, and, personally, I run it shell-less at the moment - it is pretty sturdy on its own!

It’s a seriously featureful Expansion Card - I talk more about its capabilities in the Tindie listing, there’s a few more things I’ve managed to cram into it ^~^ Will open-source the design within a day, too, just need to clean up the repositories!


Seriously impressive how much you squeezed in there! I love tightly packed boards. Please post more pictures when you get a chance. The bottom of the boards and without the USB-A jack for the dongle.


Thank you! Under the USB-A socket, there’s a 12MHz crystal and two jumper 1206 components, and on the bottom of the board, there’s just the SO16 USB hub, 3.3V reg and a few more parts, so that there’s enough clearance between the card and the chassis. Here’s a quick pic of my current card as I use it, will come home and take a few more pics!


Thanks. Honestly, it’s just fun to see how things are packed into the space.


Wow this is super cool and super tiny! I could see you also maybe fitting one of these tiny ultra fit flash drives in there for a bit of extra disk capacity:


oh in that case, here’s the KiCad PCB files! The CH334 version is a bit more packed cuz the chip has more pins, and I even managed to fit an I2C EEPROM for hub ID there… except I wired SCL up to the wrong pin =D will fix that in v2!

oh absolutely, and seems like this one would sure fit in the receiver slot^^


that is amazingly ludicrous. i didn’t even know half the acronyms in the description, i think, amazing job, and sign me up for a fully built one (with a shell), I love this.


It looks great ! Can’t wait for a shell to be available so I can buy one

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I’ll take 3 :smiley: