Steam Machine HTPC NAS ASRock N100DC-ITX

As part of the DIY Steam Machine craze, I decided to go another route. After much research inspired by other designs and on YouTube, this prototype build aims to be a home theater media PC (HTPC)/Moonlight game streaming, and a network attached storage NAS). 

Specifications:

• Size ~220mm wide by ~228mm depth x ~225mm height 

• ITX board (designed around ASRock N100DC-ITX)

• Single 140mm exhaust fan

• Up to (5) 3.5in non hot-swappable hard drives (see future expansion section)

• Removable magnetic front plate for hard drive access

• Over-complicated design, parts could have been toleranced better.

• Rough estimate of 1.5-2.5KG of filament used.

Print Recommendations

PETG. Supports should be used for the Endoframe. I increased perimeter count to 4-6 for layers where the HDD cage is to better support the load. For Rear IO Plate, I used custom cylinder shape without perimeters and set the infill to hexagonal. For Front IO and Front Plate, I printed face down on the Bambu Cool Plate SupeTack for smoother texture. As an experiment, I printed the Front Plate with gyroid infill 30-40% and removed the top layer to see if it could reduce fan and hard drive sound.

Order of Assembly + Instructions (TBD)

Base Plate -> Endoframe -> Rear IO Plate -> Front IO -> Shell -> Front Plate

1. Insert 7x 3mm brass inserts on top of base plate for motherboard standoffs and front IO plate. 1X insert is used on the bottom to lock the shell to the mobo base plate. Attach itx mobo to base plate.

2. 14x 3mm brass inserts are used in the Endoframe. Base plate is attached to endoframe using 3mm bolts underneath. 

3. 140mm fan and mobo IO shield are assembled to Rear IO plate. Use 6X 3mm bolts to attach Rear IO plate to Endoframe.

4. Front IO 

5. TBD or, see [For the Reader]

Bill of Materials

• ASRock N100DC-ITX (Purchased used from ebay w/ram, external 90W power brick)

• Storage

  • M.2 NVME drive for boot

  • Reused 3X HDDs

  • Hard Drive Cage 5.25in to 5X 3.5in ~$21

  • ASM1164 PCIe X4 SATA low profile expansion card ~$35

    • includes SATA power and data cables

• Cooling

  • ARCTIC P14 Pro 140mm PWM Fan ~$10

  • 80mm fan for CPU w/ 3D printed fan adapter

• Front IO

  • YINGAYOU USB 3.0 Front Panel Cable Extension with Panel Mount Holes 5Gbps Motherboard 19/20pin Header Splitter to 2 USB Female (30 cm) ~$10

  • 16mm Computer Case Momentary switch ~$9

• Hardware

  • 10x3mm magnets for front plate ~$9

  • 3mm brass inserts 

  • 3mm hex bolts 

  • 4X 2mm brass inserts for front USB 3.0

Future Expansion

Wolfgang said the max current of the mobo SATA power is 2A per pin. Therefore, in order to add more hard drives, I considered purchasing extra components to supply more power:

• DC ATX Peak PCU 19V 200W Pico PSU

• DC5525 Y-Splitter Cable 5.5mm X 2.5mm

• 4 in 1 power supply adapter sync starter

For the Reader

This is my first project right after learning the basics of Onshape. Check out the rough CAD model if you want to remix or understand the assembly.

Onshape Link for CAD model

Design Thoughts

The requirement to size the case to 220mm cube has made some compromises. I considered hot swappable hard drives, however decided against since the sata to sata adapter would have increased the depth beyond 220mm. A backplane would have also worked, but I wanted unrestricted ventilation for the drives. I did not include the LED light bar or recessed power button that other Steam Machine builds include. Since I'm currently satisfied with how functional the case is, I won't be doing any more modifications to address the minor issues.