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working_with_arietta

To expand the filesystem, if you installed a small-ish image, use

sudo growpart /dev/mmcblk0 2 # note there is a bug in some versions of growpart. https://launchpadlibrarian.net/481674848/growpart.patch

sudo resize2fs /dev/mmcblk0p2

Reference on Acmesystem's website: https://www.acmesystems.it/download_roadrunner


sudo stty -F /dev/ttyS0 115200

to speed up the console baud rate


Booting from the out-of-the-box SD card brings up the wifi in access point mode, at IP address 192.168.4.1. To change the wifi connection to be on your LAN wifi, try these two commands:

nmcli con down hotspot

nmcli dev wifi connect your_ssid password your_password

This has to be done from a connected serial port terminal session, since the first command drops the network.


Change the hostname!


Check wifi signal strength with: sudo while sleep 1; do /sbin/iw dev wlan0 link | grep signal; done

This device is good for experimenting with long distance wi-fi: it has an RP-SMA(?) external antenna connector in addition to its PCB antenna. Here's a quick demonstration of the additional gain from my rough prototype of a 15 element Yagi antenna:

        signal: -57 dBm
	signal: -59 dBm
	signal: -55 dBm
	signal: -57 dBm
	signal: -55 dBm
	signal: -55 dBm
	signal: -53 dBm
	signal: -49 dBm
	signal: -51 dBm <-- switched to Yagi antenna
	signal: -59 dBm
	signal: -53 dBm
	signal: -39 dBm
	signal: -37 dBm
	signal: -37 dBm
	signal: -37 dBm
	signal: -35 dBm
	signal: -37 dBm


I upgraded to Debian Buster, added a couple of useful apps, and disabled some startup things from the original set up. Archive in tgz format of the /boot and “/” (root) partitions at https://drive.google.com/drive/folders/1jf0ftLS3ZI8OIi4vddLbEFxVNSIw8685. To use it:

  • mount the SD card on another computer
  • delete everything in both partitions or reformat (partition 1 is DOS format, at least 125 MB; partition 2 ext4, at least 3 GB)
  • mount the SD card
  • dearchive the root file system contents into the second partition as root (to ensure permissions get used), e.g.:
  • cd /media/user/rootfs; sudo tar zxvf buster_files_systems.tgz rootfs
  • repeat for boot
  • cd /media/user/boot; sudo tar zxvf buster_files_systems.tgz boot
  • run sync to make sure any file buffering is done
  • umount the two partitions
  • insert SD card into Arietta, and power it up!

porting Adafruit I2C library

acme@HEX-7E44:~$ diff /home/acme/.local/lib/python2.7/site-packages/Adafruit_GPIO/Platform.py Platform.py
22a23
> import os
28a30
> ARIETTA          = 4
36a39,41
> 
>     if os.uname()[4] in ('armv5tejl'):
>         return ARIETTA

and

acme@HEX-7E44:~$ diff /home/acme/.local/lib/python2.7/site-packages/Adafruit_GPIO/I2C.py I2C.py
53a54,56
>     elif plat == Platform.ARIETTA:
>         # Acmesystems Arietta can have multiple I2C buses, default to 0 (pin 12 SCL0 and pin 14 SDA0)
>         return 0

The are three I2C ports available on the Arietta. Their pinout is described at the Acme Systems website. I used a carrier board that did not have the grideye attached to extend I2C out to some pin headers, then did it on another populated carrier.

working_with_arietta.txt · Last modified: 2022/02/12 22:48 by zwmm