This page helps to maintain some checklist (and list) related to buildroot configuration, for the purpose of small form-factor, lightweight, low power logger and network device (and possibly display).
Finally the "all-x86" nightmare is coming to an end, and some devices are now available with reasonable power consumption for the executed tasks.
Useful ARM devices (quadcore + GPU + service processor > 20 GFlops total)
- Orange PI PC family
- Zero for embedded (logging, router, wifi), 256 or 512 MB RAM
- PC Ethernet (but no wifi), 1GB RAM
- PC plus also has onboard flash (possibly faster boot)
- Lite for HDMI + wifi (but no Ethernet, and only 512MB RAM)
- H5: 64 bit version, with Gigabit ethernet (mostly for SOHO and multimedia servers, in vehicle app might not provide much benefit)
- other ...
Useful peripherals
- RS232 - TTL essential for serial datalogger, see OrangePiPc/DataLogger
- I2C RTC (normally with CR2032 battery). Useful for datalogger
- there are 2..3 popular types. The 14V => 5V SMPS is suboptimal, perhaps a low current analog 5V (or 3V or 3.3V ?) would be useful for constant 5V RTC supply.
- SPI-SD adapter
- or micro-SD
- I2C 7-segment LED 88:88
- useful for simple status display
- I2C LCD interface
- eg. for 4x20 HD44780 alphanumeric display
- I2C graphical LCD interface
- HDMI display (eg. 1280x720) and cable
- 5V2A supply
- 14V => 5V small SMPS for vehicle use
Buildroot packages and notes
- glibc (usually easier than smaller libc variants)
- socat
- rsync
- screen
- dropbear (SSH)
- mplayer
RO (readonly) root filesystem
It is highly recommended to use readonly root filesystem, and mount separate partitions for logging. Always minimize writes to SD cards.
Mount the filesystem with "noatime" option if mouning rw, if writes are really necessary.
Das u-boot
Buildroot can boot rather quickly, but some u-boot tuning might be needed to boot under 10 seconds (it takes a lot of time before kernel is actually started).