4G/wifi modem, mptcp, csi/mipi help, stickers, ...
EHLO!
A bunch of things from me, batched to avoid spamming the list excessively:
* giving out a 4G->wifi modem
* flaky 'Net? MPTCP-enabled ssh packages to rescue
* Arducam ToF -- looking for a clue wrt csi/mipi
* beef with knitted fabric
* sticker making (sadly, for after-DebConf)
* misc toys
* hair/nail coloring
4G modem
========
Tethering a computer to GSM network is something that's included in any
non-ancient spyphone, thus most of us don't need additional hardware.
But for those who do resist spyphones, I brought my old modem. Shame to
say, I recently gave up wrt not using a spyphone myself (because $REASONS),
but to prevent e-waste: someone might want to take my old modem.
It's a small thing, battery powered, takes a SIM card to provide a wifi
hotspot.
MPTCP-enabled ssh
=================
The 'Net often goes out? You bought a local SIM for that. But you can't
switch without much cursing as you notice it actually went down, you also
lost all your interactive sessions, and so on.
Same when you're at home:
* the landline ISP can't locate their nether regions even using their
entire complement of appendages
* your phone is phony (and phone latency sucks, too)
Or at a datacenter:
* your server has multiple fat network cards, but banding is limited to
a local hop only
Thus, there's a thingy called MPTCP that lets TCP use multiple connections
at once. If they're of grossly different quality (like, wired vs phone),
actual data will go through only one path, but the other one will be kept
warm so they can be switched in milliseconds.
A previous version of the protocol was there since 2014 or so, but it wasn't
so hot. Thus, an incompatible version has been made, merged into Linux 5.6
(although there are bits such as mixing IPv4 with IPv6 paths that require
kernels newer than Bookworm's). All that you need is to enable it.
Because the 'Net during DebCamp was not quite reliable, I prepared a set
of patched ssh packages, built for Sid and Bookworm:
https://angband.pl/debian/pool/main/o/openssh/
(https://angband.pl/deb/archive.html has the apt key if you prefer)
You can either:
* install the above packages, change both /etc/ssh/ssh_config and
sshd_config to UseMPTCP=yes
* or run ssh and sshd via mptpcize
* or use other ways to enable it globally/semi-globally
Tell the kernel what your external connections are (apt install mptcpd
or do "ip mptcp" by hand. Also, network managers dislike the concept of
multiple connections and might sabotage all but one of them -- eg. by
not providing a route, even for packets whose source address is set.
Then, ssh somewhere, yank the wifi cable -- and you should still be online.
Both the kernel and these packages go to extreme lengths to silently fall
back to regular TCP in face of anything missing -- thus mptcp might be not
working for some weird reason, but at least you still have regular ssh.
In particular, connections to old kernels/ordinary sshd/etc work as before.
Arducam ToF camera
==================
I brought a 3D camera, with intention to troll that hacklab TV and
otherwise have people gape in awe -- but somehow I can't get it to
work. It uses a regular csi/mipi interface, and is supposed to
present itself as an ordinary camera, but it turns out it exceeded
my non-existent mipi/... skills.
I decided to reprioritize and do other stuff during the DebConf --
but if someone more skilled would want to play with it, it's all for
you this week.
It works by sending a ping for every pixel of the image, measuring the
time it took to return. This gives a depth field, and because this
camera has a short range (2m in "short mode", 4m in "long"), the pixel
clock is quite awesome, giving high-resolution images at a high
frame rate.
It's possible the fault is not the camera's but the computer attached
to it -- if you have your own hardware with a mipi connector, that
might work, too.
beef with knitted fabric
========================
On a past DebConf (11?) we had a knitting BoF. I have an Ox64 computer
that I haven't yet found an use for -- but, given that a few of my old
friends work on something that uses libfabric heavily, there's a trolling
opportunity. What if I we made an 𝑒𝑚𝑏𝑒𝑑𝑑𝑒𝑑 machine, by driving a thread
through Ox64's holes (meant for soldering in extra goldpins, but left
unused on my piece), and knitting a piece of fabric around it, thus
embedding the machine?
Alas, my own dexterity is crap -- thus, while I can produce unique and
robust King of Macedonia grade knots, it'd be not so good for giving
results that are good for keeping on-lookers stupefied.
Nattie said the holes are too small for typical thick needles, but my
skills are inadequate to say if that's a blocker or not.
sticker making
==============
Alas, all I can give for now is a status report, admitting to a temporary
failure -- but, prognosis for the future is good. On the previous DebConf,
I looked into how we can obtain custom stickers cheaply, in bulk, on our
own. Otherwise, you need to pay exhorbitant prices to order elsewhere (see
eg. Luna's mails).
What's required:
* a cutting plotter (I got a Silhouette Portrait 3, $250)
* a decent color laser printer (a Brother for $250)
* sticker paper ($6 per 100×A4 sheets)
making printer ink the main marginal cost.
I got the plotter working shortly after DebConf22, almost done except for
cutting in wrong places -- but, worst case, if I wont find a better way,
I'd need to scale images that are sent to the plotter. That's a pair of
linear equations (scale and offset, X and Y) that might possibly be within
my remaining math skills.
The plotter was then gathering dust for almost a year. Not having a good
printer to abuse anymore, I recently bought one for my own; CUPS is still
quirky and in general staining mangled corpses of dead trees requires much
black magic that's not meant to be known by {,wo}men. But hey, after a
bunch of fails it suddenly fixed itself, yay!
So I was _almost_ there, but thanks to my stellar time management it was
time to get to DebConf.
Thus: I hereby request you folks to help me stave off procrastination by
shouting at me "are stickers done?!?" at regular intervals. In return,
you can get some of the products.
Input: a SVG file with two layers, one with the payload (a regular image),
and another that gives lines where to cut. The software is pretty good
at handling complex shapes, but a sticker obviously needs some physical
strength thus there should be no too flimsy bits.
It's probably best to stick to the hexagon standard: https://sticker.how/
-- if you remember that the orientation is vertex up, they give surprisingly
good utilization of laptop cover space; in theory, squares would be better,
but people can't stick to consistent sizes, thus hexagons are it.
Any print jobs you'd have is not required to be related to Debian. I'd
obviously be reluctant wrt:
* a hindu/jain luck symbol
* druidic nail injection
* Zorro's logo
but U+20E0 can make even those acceptable.
No guarantees of the stickers being done -- but, I can guarantee you that,
due to my procrastination standards, they will 𝑛𝑜𝑡 be done unless you
provide abundant enough shoutage. This is also the help I'm hereby
requesting.
misc toys
=========
So I have lots and lots of odd hardware bits like 1-inch 128x64 screen,
radio tx/rx that's supposed to be capable of intercepting
lightbulb/power/etc remote control (and a HOWTO I've been reading at the
time suggested to solder that to an USB _sound card_ dongle...), random
sensors, plenty of UART connectors, etc. Heck, UART connectors even be
useful sometimes. But I lack any real skill messing with those...
Thus: if this kind of toys are something you like to play with, please get
to me. And don't be afraid to break them -- after all, most of us here
are on Sid rather than Bookworm for a reason.
hair/nail coloring
==================
There's been a tradition (since DC9 I'm told) to color hair. But, it
should be done right. I can point to some examples from previous DebConfs
how 𝑛𝑜𝑡 to do that (but for obvious reasons won't give names). So...
has anyone done the research how to do it properly?
Eg. in Brazil I was so envious of ladies sporting that look with black
hair with red flame ends. Obviously, that won't work on me as somehow
since ~20 years ago my top hair stopped growing -- but it's not like
there's a lack of designs that would work for me.
I tried coloring my middle hair pink, but the result was a disaster.
A nasty dirty rusty disaster. Apparently to get any lighter colors
I'd need to first permanently lighten my beard, which is troublesome
and tends to destroy the hair, requiring further maintenance which I'm
ignorant of. And opaque paint doesn't work. Dammit. Thus, there's
𝑟𝑒𝑠𝑒𝑎𝑟𝑐ℎ that would need to be done -- but I'd be surprised if no one
of people here hasn't already done so.
In turn, I can share my results wrt nails.
In short:
* fingernails: don't. The paint lasts only 1-2 days no matter what the
bottle says -- even if you wear rubber gloves to do the dishes and
anything of the kind. And, especially in places like Poland, you're
likely to get beaten during the first bus ride you do. I've rode
without gloves (which look odd outside winter, and climate change made
winters an unthing) just once, and despite it being a route between
my home and Intel/airport area where hardly any "patriots" live, the
odd looks I got were telling enough. So don't.
* toenails: with the same technique of applying, they last a whole month
even for stuff that's advertised as "lasting even up to 7 days". And
that's with frequent showering, sitting in socks on a plane, without
socks in the hacklab, etc.
* overapply not underapply. The overflow will go onto your skin, and
skin gets naturally cycled (as evidenced as eg. bad dirt going away
after a day by itself). Thus, even if you don't get rid of overages,
which is hard with a lack of experience and low manual dexterity,
stuff will fix itself after that day or two. Out of the whole month
that toenails last for.
Given that with India temperatures it's 𝑖𝑛𝑠𝑎𝑛𝑒 to sit in European shoes,
and you have bought those havaiianas in Brazil (haven't you?), let's start
a toenail tradition like that one for hair.
Male toes are physically same as female (at most scaled up), so why would
paint there work any worse?
</rant>
[And this mail scored exceedingly high on l.d.o SA score (originally sent
Sunday); if it goes through, mighty thanks to formorer & Sledge.]
Meow!
--
⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢠⠒⠀⣿⡁ Q: Is it ok to combine wired, wifi, and/or bluetooth connections
⢿⡄⠘⠷⠚⠋⠀ in wearable computing?
⠈⠳⣄⠀⠀⠀⠀ A: No, that would be mixed fabric, which Lev19:19 forbids.
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