An experimental cyberdeck.

RASP/UTIN is the name of an ongoing project started in 2020 with the goal to build a mobile, low power, keyboard-only workstation. It currently is in its second revision.

Hardware

Raspberry Pi 4B 8GB RAM (85 x 56 x ~20mm)
7" Waveshare Display Rev 2.1 (1024×600, 156.9 x 124.27 x ~15mm)
Powerbank Green Cell Power Play 10.000 mAh 18W (140 x 72 x 14.1mm)
Planck EZ Keyboard (233 x 80 x 30mm)
Transcend RDF5K SD Cardreader USB 3.2 (24 x 56 x 9mm)
Elesa+Ganter Zink Die Cast Hinges GN 237-ZD (39 x 30 x 4 mm)
Joy-it Armor Case BLOCK ACTIVE Heatsink
LINDY HDMI-A to HDMI-Micro-D 41680 (0.50 m)
Delock Swan Neck USB-A to USB-A plug socket 83498 (0.35 m)
4 x Polyamid Spacer Bolts (6 mm x 35 mm, M3)
8 x Stainless Steel Countersunk Screws DIN 965 (10 mm, M3)

Software

dietPi - a debian derivated optimized for performance
lxde - a minimal desktop environment
i3wm - a window manager suite optimized for keyboard usage
i3bar - a status bar for i3wm
rofi - a dmenu replacement for launching applications
lightdm - a display manager
lightdm-gtk-greeter - a login greeter
gcc - the GNU compiler collection for C and C++
nnn - a terminal based file manager
micro - a terminal based text editor

Prototype

Mounting the hardware on handcut wooden boards to test size and hardware setup.

201122 | The first prototype was to test the size and the hardware.

Revision 1

The first proper case was designed in Inkscape, then modelled in Blender and then sent to a wood model store nearby that laser cut the parts.

201222 | The parts were laser cut from 5mm cottonwood boards.

201222 | Removed the case of the SD Card reader to save space.

201222 | Finished revision 1. Practically unusable due to improper fitting.

Lessons

USB plugs are longer and move less far into the slot than expected.
Plywood becomes fragile at high levels of detail. Use dot shaped holes instead of slits for air circulation.
Reposition Raspberry Pi to better fit USB cables.
Long, skinny screws are nonsense. Glue the layers right away next time.
Case top needs to be increased by two layers to fit heatsink block.
Plastic hinges feel cheap and unstable. Try to source metal hinges.

The cross hatched air slots look nice, but are fragile and broke quickly.

Revision 2

The second revision was directly planned in the vector files - the model didn't get an update.

The size was substantially increased to make plugging USB cables possible. An active heatsink was added increasing the height of the case.
The case was painted and received more attention to details. To prevent scratches and marks I added small bumpers with a glue gun. The hinges were replaced with metal ones and the case layers were glued right from the start.

220519 | Hand painted wooden inserts for the logo.

Lessons

The active heat sink is a nice addition, but not strictly necessary. Ditch it if you want to save space.
The design requires a bit of tape to make the parts stay in place when the case is flipped.
The SD card cover is too tight and makes it difficult to insert SD cards. Ditch the cover and use tape next time.
The more flexible the cables the better. Use cloth covered or flat cables if possible.
The top is too heavy and doesn't stand without external support. Try to source hinges that lock in at the right angle next time.
Laser cut wood inserts are easy to do and look slick.
Use shorter screws for the hinges and paint them black to match the rest.
Painted wood scratches easily and leaves marks on surfaces.
Ditch the SDCard Reader and use the remaining USB slot that for external storage and file transfers.

Revision 3

This version has not been produced yet. The SDCard reader is removed altogether and a few minor adjustments werde made to improve stability and comfort.

Links

incoming(4) | workstation | planck ez | review 2022 | review 2020