nakamochi 3D designs

the repo contains 3D models of parts used in the nakamochi project.

those design sources which are made with freecad use a version no older than v0.20. a stock installation of freecad should be sufficient but you might want to install fasteners workbench if working on a design assembly.

there are currently designs only for the NERD edition. KAFI version is coming later on. generated files like STL, STEP and DXF are attached to their respective releases on https://git.qcode.ch/nakamochi/3d/releases

NERD edition

this version features a custom heatsink combined with the bottom plate, suitable for aluminium CNC milling. the construction provides a good heat dissipation, making an active cooling like a fan redundant.

the baseplate serving as a heatsink brings down the main CPU temperature from around 70℃ to 50℃. when measured externally while doing bitcoin initial blocks download, an IR camera showed around 36℃.

the main file nerd.FCStd contains all parts as well as the assembly. a complete assembly BOM is as follows.

off the shelf parts

• raspberry pi 4 model b
• waveshare 4.3inch DSI LCD
• sandisk portable 1TB SSD sdssde30-1t00
• 90 degree angle USB-C adapter 3.1 gen 2, 10Gbps
• adhesive gasket/seal tape for LCD, 1mm thick, 10mm width, L370mm
• 3 thermal pads 1.5mm thick, 424mm sq total area - see baseplate drawing
• 7 screws M2.5 L10mm
• 4 adhesive bottom pads Ø5mm, 3mm+ thick

other parts, harvested from the above list:

• 2 self-tapping screws 2.9mm L3mm (from the SSD)
• 1 screw M2.5 L5mm (from the LCD)
• 4 PCB standoffs M2.5 L30mm (from the LCD)

custom parts

• CNC milled aluminium baseplate (look for baseplate_techdraw_c.pdf in releases)
• 3D-printed enclosure box (look for box.stl in releases)
• 3D-printed SSD support plate (look for ssdsupport.stl in releases)
• 3 Ø3mm hole 2.4mm thick spacers (use spacer_3x2.4mm.stl for 3D-print)

TODO: assembly instructions

assets

various files are placed in the assets to use in an assembly composition. for example, you'll find a 4.3inch display, raspberry pi 4 and a heatsink in there.

when creating a design assembly, make a new std part group and import desired assets into it. if an asset is in a freecad file format, open the file and drag&drop the top level object into the newly created std part. then close the original file ignoring the changes.

license

CC-BY 4.0