Fido Passkey RP2350-Zero keychain case (Picokeys)

Build your own FIDO2 passkey using the https://www.picokeys.com/ - https://github.com/polhenarejos/pico-fido firmware and enclosing it in this rugged and small case.

❗IMPORTANT: You need to adjust print settings, otherwise the print will fail and your PCB will be broken!

The Waveshare RP2350-Zero PCB will be added during printing with a pause command to your printer, and the rest of the case is printed directly on top. This leaves the PCB tightly enclosed into the print without any seams.

Partslist:

Note: The RP2350 Zero is not perfect. It has a faulty USB C implementation, meaning that it will only work if you plug in the USB C cable the right way. If you device does not start up, flip the USB C plug 180 degrees.

NOT compatible with the RP2040-Zero!

Print settings:

It is critical you change the following print settings (paths from Bambu Studio):

• Quality -> Advanced -> Avoid crossing wall

  • This is critical, as otherwise the nozzle will crash into components on your PCB breaking it!

• Speed -> Bridge 10 mm/s

• Speed -> Change all Overhang speeds to 10 mm/s

  • A slow bridge and overhang speed is critical for proper adhesion to the PCB

Recommendations:

• Speed -> Travel speed 100 mm/s

• Speed -> Change all speeds to a maximum of 50 mm/s

• Speed -> Change all accelerations to a maximum of 2000 mm/s^2

  • With fast movements and accelerations, the PCB can be lifted up from your part

  • This print is tiny, so speeds are not that important. Slow speeds makes it easier for the PCB to settle in properly

• Enable top surfaces ironing

I have printed this part from both PETG and PLA succesfully using a 0.6mm nozzle. I believe a 0.4mm nozzle would work as well. I use top surfaces ironing to have less variation in the push button gap.

Layer heights:

The push button tactile feedback is incredibly sensitive to changes in the button gap.

I highly recommend sticking to the following print settings:

• Always 0.3mm first layer height

• Start by using the 0,7mm model with 0,19mm layer height. This will result in a 2,47mm gap for the switch.

  • If your push button is difficult to press and does not click, decrease the button gap by 0.1mm

  • If you push button stays pushed in and does not release, increase the button gap by 0.1mm

• Print a few times to find the gap that works best for you

Adhesion to PCB:

Apply PVA glue or glue stick to the PCB to allow the filament to stick to it while printing. The filament does not stick to the PCB soldermask otherwise. Apply two coatings of PVA to the highlighted areas for best results:

Print pause for inserting the PCB:

After slicing, add a pause at the start of the first overhang layer

 Changelog: