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:
cd /media/user/rootfs; sudo tar zxvf buster_files_systems.tgz rootfs
cd /media/user/boot; sudo tar zxvf buster_files_systems.tgz boot
sync
to make sure any file buffering is doneporting 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.