Some Expansion Cards I Have Been Working On

I am experimenting with several ideas for expansion cards and I thought some of you might be interested. I have a rough expansion for an Adafruit QT Py RP2040, a foot extension that increases the height of the back of the laptop, and a dongle hider card. The QT Py expansion is basically just a custom short USB cable and mounting for the PCBs, yes the USB connectors are held in with hot glue, I am not proud of it but it provided a convenient solution.

Next The foot extension is designed to fit around the existing rubber foot and be held in place by the rear two card slots. To remove the extension you just have to slide out at least one of the two locking cards. The long foot won’t fit onto my print bed so it is split in half with a 3mm hole for m3 rod to provide extra rigidity after gluing the halves together.

The dongle hider is pretty simple, it is specifically designed for a Logitech unify nano receiver (model c-u0012) and is basically just a notch to let the dongle sit flat and keep it from sliding. Presently I haven’t decided wether or not I want to further secure the dongle, it seems relatively secure, so for now, I am going to leave it. Also a quick shout out to whoever posted a link to these low profile USB a-c adapters, I can’t find the post but they made my life way easier, so thanks.

I have included a dongle hider/foot mount combo card if you want to do both at once.
Here is a link to the 3mf files, if anybody wants another file format (f3d, step, etc.) let me know and I can add them.

edit: added a loft to the foot smoothing a rough edge


Awesome work. The foot extension would be especially interesting to combine with (to-be-developed) taller expansion cards that could fit multiple USB-C/As, etc.

Oh the humanity! Hot snot, beautiful.


I’m glad I was able to find them and somebody found an alternate supplier on Amazon after the first ones sold out. I’ve seen them on eBay as well.

I love the idea of a combo foot extender to help with cooling and the dongle hider, now I just need to figure out how long of a “port extender” I would need to have a dongle hider on one side and a Yubikey Nano USB-A or Nitrokey 3A on the other with the tip slightly recessed so it is impossible to accidentally bump, but still possible to touch to activate.

I’m not sure I understand what you are saying here, can you elaborate?

Essentially instead of the USB-A module which would put the above security keys outside of the frame and really easy to bump, I want a USB-A port recessed one to three millimeters so that to activate requires pushing my finger against the edge of the frame to get a little bit of my finger tip inside to touch that contact.

In the past what I ended up resorting to was one of those USB extension cables you used to use for a wireless card or mp3 player that stood it up in a weighted base so that the contact was easy to hit but not easy to hit accidentally like if I were repositioning the laptop on my lap or going to pick it up to put into my bag.