I have used the following credit-card sized single-board computers.

  • Raspberry Pi family
  • BeagleBone Black family
  • Rock64

My preference is for the BeagleBone Black family, with the Green Wireless from SeeedStudio as my favourite.

BeagleBone Green Wireless

  • All of the BeagleBone family have on-board eMMC for the main filesystem, rather than SD card
  • 4 USB ports
  • WLAN and Bluetooth, with on-board chip antenna and 2 u.FL connectors for external antennas
  • Connector for standard FTDI cable
  • Lots of GPIOs, various serial port, CAN, etc
  • No on-board HDMI framer (I thinik), so those pins can be used as GPIO; I don’t need video
  • Schematics, PCB layout and documentation for all of the devices available
  • No proprietary stuff
  • Modern Debian 11 (Bullseye), programmable via SD card socket

Disadvantages

  • Old components
  • Rather slow
  • Small RAM
  • No on-board DC power connector. Power comes from the micro USB socket, or you can supply power from a piggy-back board (‘cape’) via the 5 V pin.
  • Very few piggy-back boards available
  • Small community

I like the look of the BeagleBone Green Gateway (also from SeeedStudio), but I have not used it.

  • Similar to BBGW
  • On board DC power connector, with input range 5 – 28 V
  • Ethernet, WLAN, Bluetooth
  • 2 USB ports

Raspberry Pi

  • Huge community
  • Lots of add-on boards
  • SD card is not reliable as the primary file system
  • Proprietary main process; no documentation available
  • Ethernet via USB

Rock64

  • For its time, it was a very powerful processor
  • GB Ethernet
  • One ?? (fast) USB port
  • 4 standard USB ports
  • Proprietary processor; no documentation available
  • Small community, poor software support