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An SBC-based computer designed to replace a laptop
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contrapunctus 6758f04857 [SBCs] add Odroid H2+ 2021-08-29 14:37:44 +05:30
README.org [SBCs] add Odroid H2+ 2021-08-29 14:37:44 +05:30

README.org

Aims

  1. replace a laptop
  2. no hardware backdoors (excludes Intel and AMD)
  3. more or less as easy to carry as a laptop

  4. cheap and easy to build, repair, and upgrade

    • made from and upgradable with commonly- and cheaply-available components
    • no dependence on any single company's (dis)service centers, nor proprietary parts or standards.
  5. minimum 3-4 hours of battery life (idle with the screen on)
  6. occasional RAM-heavy use e.g. web browsing, video editing, orchestral sampling
  7. no flimsy parts - built to last

Design strategies

Square brackets indicate a single unit enclosing the listed components -

Keyboard-integrated

monitor/phone/tablet/TV + [keyboard, storage, RPi, battery, speaker(s)].

Existing examples

  1. Raspberry Pi 400

Monitor-integrated (AKA all-in-one)

keyboard + [monitor, storage, RPi, battery, speaker(s)].

Compact desktop

Monitor/phone/tablet/TV + keyboard + [storage, RPi and battery]

  • probably the best solution in terms of heat dissipation

Existing examples -

Most such designs I've seen stack the components on top of each other, which results in a cube/tower-like enclosure which would be difficult for me to keep in a backpack or laptop bag. What if the SBC, battery, and hard disk were laid out side-by-side? The resulting enclosure would be like a thick book, hopefully easy to place in bags.

laptop housing

laptop housing + (if space available) external keyboard

Existing examples -

  1. Olimex TERES-I (€240) - the aims are very much in line with mine, but it has just 2GB RAM and 2 USB ports, and the user seems to be dependent on Olimex providing newer main boards to upgrade it.
  2. Elecrow CrowPi2 - the keyboard is actually a Bluetooth keyboard which can just be lifted off while the computer is running - nice! On the other hand, I'm not a fan of the finish on the plastic body, it has a ton of sensors and stuff I don't need, and it does not have a trackpad.

Components

Buy used wherever possible.

DONE SBC

Preferences

  1. Usable for a desktop, especially memory-hungry programs like Tor Browser and tasks like MIDI sampling.

    • check Lisp implementation support
  2. minimum 4 GB RAM
  3. audio output
  4. minimum 4 USB ports
  5. PCIe or SATA

Options

Raspberry Pi 4B 8GB
  • more RAM than I've ever had on any machine, cheap (as low as ₹5.8k), popular
  • no SATA (AFAIK), so each hard disk consumes a USB port
NanoPi M4 (shop)
  • Dual-Channel 4GB LPDDR3-1866 RAM
  • 4× USB 3.0 Type-A ports
  • 1× USB 2.0 Type-C OTG and Power input

  • PCIe x2

    • how fast will this be for SATA?

      psydroid: > PCIe: One PCIe port Compatible with PCI Express Base Specification Revision 2.1
      psydroid: it should support 2 drives at full speed (6 Gbps)
      psydroid: however hard drives will never use up all that bandwidth

NanoPC T4
  • Dual-Channel 4GB LPDDR3-1866 RAM
  • 2× USB 2.0 Host Type-A
  • 1× USB 3.0 Host Type-A
  • 1× USB Type-C 3.0
  • 1× M.2 M-Key PCIe x4 socket, compatible with PCIe 2.1
Helios4
  • just 2GB RAM, just 2 CPU cores, but 4 SATA ports
Hardkernel Odroid H2+
  • ₹13.3k on FabToLab
  • SO-DIMM slots for RAM - expandable, up to 32GB!
  • 1× M.2 NVMe ("4× PCIe 2.0"?)
  • 2× SATA 3.0
  • 2× 2.5Gbit Ethernet
  • 1× HDMI 2.0 and 1× DisplayPort 1.2
  • RAM must be purchased additionally; no WiFi or Bluetooth built-in
  • probably too large for anything other than a standalone box

Active cooling

RESEARCH Screen

Preferences

  • 15"
  • touchscreen

Search notes

Couldn't find this anywhere - Raspberry Pi 4 15.6" Portable IPS Touchscreen Monitor

Found these. Not enthused.

The largest screens on PiHut are some 10" touchscreens.

Digikey - display modules between 15" to 20"

I was amazed to see what I thought was a 15.6" touchscreen for just €70, but it's actually just a touch panel (with no display), and not even meant for outdoor use - Olimex LCD-TS15.6

Options

Olimex has something for us.

How do I connect these to the Pi?

Power

Battery

I'd like to use LiFePo₄ batteries, like the MNT Reform does - "more fire-safe and has more charge-cycles than LiPo battieries."

Power management

<wgreenhouse> the issue is the pi has no power management features itself (other than brownout/undervolt warning in firmware), so you either need a complex "daughterboard" to help, or to just accept that the pi has no control over power management (as in the many attempts that just stick the pi on a usb powerbank)

Quite a few power management HATs available - PiHut.

What do I look for?

Storage

Perhaps I can reuse a hard disk from an old laptop? Would that require anything other than a SATA HAT?

USB hub

Hopefully, connecting a USB keyboard and a wireless mouse to a hub does not result in any problems, and saves one USB port.

"a simple unpowered hub would be fine for those" — wgreenhouse

DONE Keyboard and mouse

I have a TVSe Gold Prime and a Logitech M215 I'd like to reuse.

Webcam

Speakers and microphone

Other cool projects

  1. MNT Reform - if it had finance options, that's probably what I'd be getting.
  2. EOMA68 - what I really had my hopes pinned on before I knew of the MNT Reform. Cool ideas all around. Succeeded in crowdfunding in 2016-08, still hasn't shipped as of 2021-08.
  3. r/cyberdeck and rfox's cyberdeck page.