August 23, 2022

Inside my BBB based macro focus stand

This is based on a BBB (beagle bone black) single board computer. This is an ARM based board running Angstrom Linux. The following is a play by play as I fire it up and poke around.

ssh access - update as of 3-23-2023

After spending 20 minutes or so trying to persuade the ssh client on a modern Fedora linux machine to connect, I took one suggestion and installed putty.

Now I can do "putty focus" and then get right in as "tom". Hooray!

ssh access - back in 8-23-2022

It comes up as 128.168.0.131 on my local network, getting its identity via DHCP. It boots the dreadful and hated Angstrom linux.

It is running a web server of some kind on port 80, but it simply spits out an advertising page for the BBB that talks about Bonscript and Cloud9, which are wretched things I never intend to use.

I try to ssh to it, but it is running some ancient sshd and I get: 

Unable to negotiate with 192.168.0.132 port 22: no matching key exchange method found.
Their offer: diffie-hellman-group1-sha1,diffie-hellman-group14-sha1
All the more reason to move to a newer debian with this project. There is a client side work around: 
ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 focus2
This is usually worth it, because the resulting session has sane "stty" settings, so if you try to use the "vi" editor for example, it won't be a train wreck.

I put this into a script named "focus" on my server.

Angstrom workarounds

Typing "stty cols 200" yields longer lines from things like "ps -alx".

And another angstrom irritation -- no file name completion! You don't realize what habits you have and what you take for granted until something like this turns up missing. I have tried, but there is no workaround for this -- so find some way to ditch Angstrom linux (such as migrating to Debian).

How to run my application

This will run a server on port 1776. Note that doing this as user tom does not work (you get a message that it cannot find "bonescript").

Now chrome gives me a headache as it tries to search rather than just going to an explicit URL that I give it. Firefox is equally stupid. Using one of these links will work:

Sometimes it does work typing "http://focus2:1776", but the above links may be more convenient, at least if I have this page up.

I give several since my DHCP jumps around some and I don't want to figure out how to set a static IP using Angstrom. I can get the BBB mac address and lock down my DHCP server. <-- C4:ED:BA:7C:34:2F -->

Feedback? Questions? Drop me a line!

Tom's Computer Info / tom@mmto.org