co2mon.nz currently uses monitors based on Oliver Seiler s open source design which I am personally building. This post describes my exploration of how to achieve production of a CO2 monitor that could enable the growth of co2mon.nz.
Goals
Primarily I want to design a CO2 monitor which allows the majority of the production process to be outsourced. In particular, the PCB should be able to be assembled in an automated fashion (PCBA).
As a secondary goal, I d like to improve the aesthetics of the monitor while retaining the unique feature of displaying clear visual indication of the current ventilation level through coloured lights.
Overall, I ll consider the project successfull if I can achieve a visually attractive CO2 monitor which takes me less than 10 minutes per monitor to assemble/box/ship and whose production cost has the potential to be lower than the current model.
PCB
Schematic
The existing CO2 monitor design provides a solid foundation but relies upon the ESP32 Devkit board, which is intended for evaluation purposes and is not well suited to automated assembly. Replacing this devkit board with the underlying ESP32 module is the major change needed to enable PCBA production, which then also requires moving the supporting electronics from the devkit board directly onto the primary PCB.
The basic ESP32 chipset used in the devkit boards is no longer available as a discrete module suitable for placement directly onto a PCB which means the board will also have to be updated to use a more modern variant of the ESP32 chipset which is in active production such as the ESP32-S3. The ESP32-S3-WROOM1-N4 module is a very close match to the original devkit and will be suitable for this project.
In addition to the change of ESP module, I made the following other changes to the components in use:
Added an additional temperature/humidity sensor (SHT30). The current monitors take temperature/humidity measurements from the SCD40 chipset. These are primarily intended to help in the calculation of CO2 levels and rely on an offset being subtracted to account for the heat generated by the electronic components themselves. I ve found their accuracy to OK, but not perfect. SHT30 is a cheap part, so its addition to hopefully provide improved temperature/humidity measurement is an easy choice.
Swapped to USB-C instead of USB-B for the power connector. USB-C is much more common than USB-B and is also smaller and not as tall off the board which provides more flexibility in the case design.
With major components selected the key task is to draw the schematic diagram describing how they electrically connect to each other, which includes all the supporting electronics (e.g. resistors, capacitors, etc) needed.
I started out trying to use the EasyEDA/OSHWLab ecosystem thinking the tight integration with JLCPCB s assembly services would be a benefit, but the web interface was too clunky and limiting and I quickly got frustrated. KiCad proved to be a much more pleasant and capable tool for the job.
The reference design in the ESP32 datasheet (p28) and USB-C power supply examples from blnlabs were particularly helpful alongside the KiCad documentation and the example of the existing monitor in completing this step (click the image to enlarge).
Layout
The next step is to physically lay out where each component from the schematic will sit on the PCB itself. Obviously this requires first determining the overall size, shape and outline of the board and needs to occur in iteration with the intended design of the overall monitor, including the case, to ensure components like switches and USB sockets line up correctly.
In addition to the requirements around the look and function of the case, the components themselves also have considerations that must be taken into account, including:
For best WiFi reception, the ESP32 antenna should be at the top of the monitor and should not have PCB underneath it, or for a specified distance either side of it.
The SHT30 temperature sensor should be as far from any heat generating components (e.g. the ESP32, BME680 and SCD40 modules) as possible and also considering that any generated heat will rise, as low on the monitor as possible.
The sensors measuring the air (SCD40, BME680 and SHT30) must have good exposure to the air outside the case.
Taking all of these factors into account I ended up with a square PCB containing a cutout in the top right so that the ESP32 antenna can sit within the overall square outline while still meeting its design requirements. The SCD40 and BME680 sit in the top left corner, near the edges for good airflow and far away from the SHT30 temperature sensor in the bottom left corner. The LEDs I placed in a horizontal row across the center of the board, the LCD in the bottom right, a push button on the right-hand side and the USB-C socket in the center at the bottom.
Once the components are placed, the next big task is to route the traces (aka wires) between the components on the board such that all the required electrical connections are made without any unintended connections (aka shorts) being created. This is a fun constraint solving/optimisation challenge and takes on an almost artistic aspect with other PCB designers often having strong opinions on which layout is best. The majority of the traces and routing for this board were able to be placed on the top layer of the PCB, but I also made use of the back layer for a few traces to help avoid conflicts and deal with places where different traces needed to cross each other. It s easy to see how this step would be much more challenging and time consuming on a larger and more complex PCB design.
The final touches were to add some debugging breakouts for the serial and JTAG ports on the ESP32-S3 and a logo and various other helpful text on the silkscreen layer that will be printed on the PCB so it looks nice.
Production
For assembly of the PCB, I went with JLCPCB based out of China. The trickiest part of the process was component selection and ensuring that the parts I had planned in the schematic were available. JLCPCB in conjunction with lcsc.com provides a basic and extended part library. If you use only basic parts you get quicker and cheaper assembly, while using extended parts bumps your order into a longer process with a small fee charged for each component on the board.
Initially I spent a lot of time selecting components (particularly LEDs and switches) that were in the basic library before realising that the ESP32 modules are only available in the extended library! I think the lesson is that unless you re building the most trivial PCB with only passive components you will almost certainly end up in the advanced assembly process anyway, so trying to stay within the basic parts library is not worth the time.
Unfortunately the SCD40 sensor, the most crucial part of the monitor, is not stocked at all by JLCPCB/LCSC! To work around this JLCPCB will maintain a personal component library for you when you ship components to them to for use in future orders. Given the extra logistical time and hassle of having to do this, combined with having a number of SCD40 components already on hand I decided to have the boards assembled without this component populated for the initial prototype run. This also had the benefit of lowering the risk if something went wrong as the cost of the SCD40 is greater than the cost of the PCB and all the other components combined!
I found the kicad-jlcpcb-tools plugin for KiCad invaluable for keeping track of what part from lcsc.com I was planning to use for each component and generating the necessary output files for JLCPCB. The plugin allows you to store these mappings in your actual schematic which is very handy. The search interface it provides is fairly clunky and I found it was often easier to search for the part I needed on lcsc.com and then just copy the part number across into the plugin s search box rather than trying to search by name or component type.
The LCD screen is the remaining component which is not easily assembled onto the PCB directly, but as you ll see next, this actually turned out to be OK as integrating the screen directly into the case makes the final assembly process smoother.
The final surprise in the assembly process was the concept of edge rails, additional PCB material that is needed on either side of the board to help with feeding it through the assembly machine in the correct position. These can be added automatically by JLCPCB and have to be snapped off after the completed boards are received. I hadn t heard about these before and I was a little worried that they d interfere or get in the way of either the antenna cut-out at the top of the board, or the switch on the right hand side as it overhangs the edge so it can sit flush with the case.
In the end there was no issue with the edge rails. The switch was placed hanging over them without issue and snapping them off once the boards arrived was a trivial 30s job using a vice to hold the edge rail and then gently tipping the board over until it snapped off - the interface between the board and the rails while solid looking has obviously been scored or perforated in some way during the production process so the edge breaks cleanly and smoothly. Magic!
The process was amazingly quick with the completed PCBs (picture above) arriving within 7 days of the order being placed and looking amazing.
Case
Design
I mocked up a very simple prototype of the case in FreeCAD during the PCB design process to help position and align the placement of the screen, switch and USB socket on the PCB as all three of these components interface directly with the edges of the case. Initially this design was similar to the current monitor design where the PCB (with lights and screen attached) sits in the bottom of the case, which has walls containing grilles for airflow and then a separate transparent perspex is screwed onto the top to complete the enclosure.
As part of the aesthetic improvements for the new monitor I wanted to move away from a transparent front panel to something opaque but still translucent enough to allow the colour of the lights to show through. Without a transparent front panel the LCD also needs to be mounted directly into the case itself.
The first few prototype iterations followed the design of the original CO2 monitor with a flat front panel that attaches to the rest of the case containing the PCB, but the new requirement to also attach the LCD to the front panel proved to make this unworkable. To stay in place the LCD has to be pushed onto mounting poles containing a catch mechanism which requires a moderate amount of force and applying that force to the LCD board when it is already connected to the PCB is essentially impossible.
As a result I ended up completely flipping the design such that the front panel is a single piece of plastic that also encompasses the walls of the case and contains appropriate mounting stakes for both the screen and the main PCB.
Getting to this design hugely simplified the assembly process. Starting with an empty case lying face down on a bench, the LCD screen is pushed onto the mounting poles and sits flush with the cover of the case - easily achieved without the main PCB yet in place.
Next, the main PCB is gently lowered into the case facing downwards and sits on the mounting pole in each corner with the pins for the LCD just protruding through the appropriate holes in the PCB ready to be quickly soldered into place (this took significant iteration and tuning of dimensions/positioning to achieve!).
Finally, a back panel can be attached which holds the PCB in place and uses cantilever snap joints to click on to the rest of the case.
Overall the design is a huge improvement over the previous case which required screws and spacers to position the PCB and cover relative to the rest of the case, with the spacers and screws being particularly fiddly to work with.
The major concern I had with the new design was that the mount to attach the monitor to the wall has moved from being attached to the main case and components directly to needing to be on the removable back panel - if the clips holding this panel to the case fail the core part of the monitor will fall off the wall which would not be good. To guard against this I ve doubled the size and number of clips at the top of the case (which bears the weight) and the result seems very robust in my testing. To completely assemble a monitor, including the soldering step takes me about 2-3 minutes individually, and would be even quicker if working in batches.
Production
Given the number of design/testing iterations required to fine tune the case I chose not to outsource case production for now and used my 3D printer to produce them. I ve successfully used JLCPCB s 3D printing service for the previous case design, so I m confident that getting sufficient cases printed from JLCPCB or another supplier will not be an issue now that the design is finalised.
I tried a variety of filament colours, but settled on a transparent filament which once combined in the necessary layers to form the case is not actually transparent like perspex is, but provides a nice translucent medium which achieves the goal of having the light colour visible without exposing all of the circuit board detail. There s room for future improvement in the positioning of the LEDs on the circuit board to provide a more even distribution of light across the case but overall I really like the way the completed monitor ends up looking.
Evaluation
Building this monitor has been a really fun project, both in seeing something progress from an idea, to plans on a screen to a nice physical thing on my wall, but also in learning and developing a bunch of new skills in PCB design, assembly and 3D design.
The goal of having a CO2 monitor which I can outsource the vast majority of production of is as close to being met as I think is possible without undertaking the final proof of placing a large order. I ve satisfied myself that each step is feasible and that the final assembly process is quick, easy and well below the level of effort and time it was taking me to produce the original monitors.
Cost wise it s also a huge win, primarily in terms of the time taken, but also in the raw components - currently the five prototypes I ordered and built are on par with the component cost of the original CO2 monitor, but this will drop further with larger orders due to price breaks and amortisation of the setup and shipping expenses across more monitors.
This project has also given me a much better appreciation for how much I m only just scratching the surface of the potential complexities and challenges in producing a hardware product of this type.
I m reasonably confident I could successfully produce a few hundred and maybe even a few thousand monitors using this approach, but it s also clear that getting beyond that point is and would be a whole further level of effort and learning.
Hardware is hard work. That s not news to anyone, including me, but there is something to be said for experiencing the process first hand to make the reality of what s required real.
The PCB and case designs are both shared and can be found at https://github.com/co2monnz/co2monitor-pcb and https://github.com/co2monnz/cad, feedback and suggestions welcome!
Review: The Story of the Treasure Seekers, by E. Nesbit
Publisher:
Amazon
Copyright:
1899
Printing:
May 2012
ASIN:
B0082ZBXSI
Format:
Kindle
Pages:
136
The Story of the Treasure Seekers was originally published in 1899
and is no longer covered by copyright. I read the free Amazon Kindle
version because it was convenient. My guess is that Amazon is
republishing the Project
Gutenberg version, but they only credit "a community of volunteers."
There are six Bastable children: Dora, Oswald, Dicky, the twins Alice and
Noel, and Horace Octavius (H.O.), the youngest. Their mother is dead and
the family's finances have suffered in the wake of her death (or, as the
first-person narrator puts it, "the fortunes of the ancient House of
Bastable were really fallen"), which means that their father works long
hours and is very absorbed with his business. That leaves the six kids
largely to fend for themselves, since they can't afford school. Clearly
the solution is to find treasure.
This is a fix-up novel constructed from short stories that were originally
published in various periodicals, reordered and occasionally rewritten for
the collected publication. To be honest, calling it a fix-up novel is
generous; there are some references to previous events, but the first
fourteen chapters can mostly stand alone. The last two chapters are
closely related and provide an ending. More on that in a moment.
What grabs the reader's attention from the first paragraph is the writing
style:
This is the story of the different ways we looked for treasure, and I
think when you have read it you will see that we were not lazy about
the looking.
There are some things I must tell before I begin to tell about the
treasure-seeking, because I have read books myself, and I know how
beastly it is when a story begins, "Alas!" said Hildegarde with a deep
sigh, "we must look our last on this ancestral home" and then some
one else says something and you don't know for pages and pages where
the home is, or who Hildegarde is, or anything about it.
The first-person narrator of The Story of the Treasure Seekers is
one of the six kids.
It is one of us that tells this story but I shall not tell you
which: only at the very end perhaps I will.
The narrator then goes on to elaborately praise one of the kids,
occasionally accidentally uses "I" instead of their name, and then
remembers and tries to hide who is telling the story again. It's
beautifully done and had me snickering throughout the book. It's not much
of a mystery (you will figure out who is telling the story very quickly),
but Nesbit captures the writing style of a kid astonishingly well without
making the story poorly written. Descriptions of events have a headlong
style that captures a child's sense of adventure and heedless immortality
mixed with quiet observations that remind the reader that kids don't miss
as much as people think they do.
I think the most skillful part of this book is the way Nesbit captures a
kid's disregard of literary convention. The narrator in a book written by
an adult tends to fit into a standard choice of story-telling style and
follow it consistently. Even first-person narrators who break some of
those rules feel like intentionally constructed characters. The
Story of the Treasure Seekers is instead half "kid telling a story" and
half "kid trying to emulate the way stories are told in books" and tends
to veer wildly between the two when the narrator gets excited, as if
they're vaguely aware of the conventions they're supposed to be following
but are murky on the specifics. It feels exactly like the sort of book a
smart and well-read kid would write (with extensive help from an editor).
The other thing that Nesbit handles exceptionally well is the dynamic
between the six kids. This is a collection of fairly short stories, so
there isn't a lot of room for characterization. The kids are mostly
sketched out with one or two memorable quirks. But Nesbit puts a lot of
effort into the dynamics that arise between the children in a tight-knit
family, properly making the group of kids as a whole and in various
combinations a sort of character in their own right. Never for a moment
does either the reader or the kids forget that they have siblings. Most
adventures involve some process of sorting out who is going to come along
and who is going to do other things, and there's a constant but
unobtrusive background rhythm of bickering, making up, supporting each
other, being frustrated by each other, and getting exasperated at each
other's quirks. It's one of the better-written sibling dynamics that I've
read.
I somehow managed to miss Nesbit entirely as a kid, probably because she
didn't write long series and child me was strongly biased towards books
that were part of long series. (One book was at most a pleasant few
hours; there needed to be a whole series attached to get any reasonable
amount of reading out of the world.) This was nonetheless a fun bit of
nostalgia because it was so much like the books I did read: kids finding
adventures and making things up, getting into various trouble but getting
out of it by being honest and kind, and only occasional and spotty adult
supervision. Reading as an adult, I can see the touches of melancholy of
loss that Nesbit embeds into this quest for riches, but part of the appeal
of the stories is that the kids determinedly refuse to talk about it
except as a problem to be solved.
Nesbit was a rather famous progressive, but this is still a book of its
time, which means there's one instance of the n-word and the kids have
grown up playing the very racist version of cowboys and indians. The
narrator also does a lot of stereotyping of boys and girls, although
Nesbit undermines that a bit by making Alice a tomboy. I found all of
this easier to ignore because the story is narrated by one of the kids who
doesn't know any better, but your mileage may vary.
I am always entertained by how anyone worth writing about in a British
children's novel of this era has servants. You know the Bastables have
fallen upon hard times because they only have one servant. The kids don't
have much respect for Eliza, which I found a bit off-putting, and I
wondered what this world looks like from her perspective. She clearly did
a lot of the work of raising these motherless kids, but the kids view her
as the hired help or an obstacle to be avoided, and there's not a lot of
gratitude present.
As the stories unfold, it becomes more and more clear that there's a quiet
conspiracy of surrounding adults to watch out for these kids, which the
kids never notice. This says good things about society, but it does
undermine the adventures a little, and by the end of the book the sameness
of the stories was wearing a bit thin. The high point of the book is
probably chapter eight, in which the kids make their own newspaper, the
entirety of which is reproduced in the book and is a note-perfect
recreation of what an enterprising group of kids would come up with.
In the last two stories, Nesbit tacks on an ending that was probably
obligatory, but which I thought undermined some of the emotional subtext
of the rest of the book. I'm not sure how else one could have put an
ending on this book, but the ending she chose emphasized the degree to
which the adventures really were just play, and the kids are rewarded in
these stories for their ethics and their circumstances rather than for
anything they concretely do. It's a bit unsatisfying.
This is mostly a nostalgia read, but I'm glad I read it. If this book was
not part of your childhood, it's worth reading if only for how well Nesbit
captures a child's narrative voice.
Rating: 7 out of 10
I read this book as part of the Beyond Series Bundle (Books 1-3),
which is what the sidebar information is for.
Noelle is a child of Eden, the rich and technologically powerful city of a
post-apocalyptic world. As the daughter of a councilman, she had
everything she wanted except the opportunity to feel. Eden's religious
elite embrace a doctrine of strict Puritanism: Even hugging one's children
was frowned upon, let alone anything related to sex. Noelle was too
rebellious to settle for that, which is why this book opens with her
banished from Eden, ejected into Sector Four. The sectors are the city
slums, full of gangs and degenerates and violence, only a slight step up
from the horrific farming communes. Luckily for her, she literally
stumbles into one of the lieutenants of the O'Kane gang, who are just as
violent as their reputations but who have surprising sympathy for a
helpless city girl.
My shorthand distinction between romance and erotica is that romance mixes
some sex into the plot and erotica mixes some plot into the sex.
Beyond Shame is erotica, specifically BDSM erotica. The forbidden
sensations that Noelle got kicked out of Eden for pursuing run strongly
towards humiliation, which is tangled up in the shame she was taught to
feel about anything sexual. There is a bit of a plot surrounding the
O'Kanes who take her in, their leader, some political skulduggery that
eventually involves people she knows, and some inter-sector gang warfare,
but it's quite forgettable (and indeed I've already forgotten most of it).
The point of the story is Noelle navigating a relationship with Jasper
(among others) that involves a lot of very graphic sex.
I was of two minds about reviewing this. Erotica is tricky to review,
since to an extent it's not trying to do what most books are doing. The
point is less to tell a coherent story (although that can be a bonus) than
it is to turn the reader on, and what turns the reader on is absurdly
personal and unpredictable. Erotica is arguably more usefully marked with
story codes
(which in this case would be something like MF, MMFF, FF, Mdom, Fdom, bd,
ds, rom, cons, exhib, humil, tattoos) so that the reader has an idea
whether the scenarios in the story are the sort of thing they find hot.
This is particularly true of BDSM erotica, since the point is arousal from
situations that wouldn't work or might be downright horrifying in a
different sort of book. Often the forbidden or taboo nature of the scene
is why it's erotic. For example, in another genre I would complain about
the exaggerated and quite sexist gender roles, where all the men are
hulking cage fighters who want to control the women, but in male-dominant
BDSM erotica that's literally the point.
As you can tell, I wrote a review anyway, primarily because of how I came
to read this book. Kit Rocha (which is a pseudonym for the writing team
of Donna Herren and Bree Bridges) recently published Deal with the
Devil, a book about mercenary librarians in a post-apocalyptic future.
Like every right-thinking person, I immediately wanted to read a book
about mercenary librarians, but discovered that it was set in an existing
universe. I hate not starting at the beginning of things, so even though
there was probably no need to read the earlier books first, I figured out
Beyond Shame was the first in this universe and the bundle of the
first three books was only $2.
If any of you are immediately hooked by mercenary librarians but are
back-story completionists, now you know what you'll be getting into.
That said, there are a few notable things about this book other than it
has a lot of sex. The pivot of the romantic relationship was more
interesting and subtle than most erotica. Noelle desperately wants a man
to do all sorts of forbidden things to her, but she starts the book unable
to explain or analyze why she wants what she wants, and both Jasper and
the story are uncomfortable with that and unwilling to leave it alone.
Noelle builds up a more coherent theory of herself over the course of the
book, and while it's one that's obviously designed to enable lots of
erotic scenes, it's not a bad bit of character development.
Even better is Lex, the partner (sort of) of the leader of the O'Kane gang
and by far the best character in the book. She takes Noelle under her
wing from the start, and while that relationship is sexualized like nearly
everything in this book, it also turns into an interesting female
friendship that I would have also enjoyed in a different genre. I liked
Lex a lot, and the fact she's the protagonist of the next book might keep
me reading.
Beyond Shame also has a lot more female gaze descriptions of the
men than is often the case in male-dominant BDSM. The eye candy is fairly
evenly distributed, although the gender roles are very much not. It even
passes the Bechdel
test, although it is still erotica and nearly all the conversations end
up being about sex partners or sex eventually.
I was less fond of the fact that the men are all dangerous and violent and
the O'Kane leader frequently acts like a controlling, abusive psychopath.
A lot of that was probably the BDSM setup, but it was not my thing. Be
warned that this is the sort of book in which one of the (arguably) good
guys tortures someone to death (albeit off camera).
Recommendations are next to impossible for erotica, so I won't try to give
one. If you want to read the mercenary librarian novel and are dubious
about this one, it sounds like (although I can't confirm) that it's a bit
more on the romance end of things and involves a lot fewer group orgies.
Having read this book, I suspect it was entirely unnecessary to have done
so for back-story. If you are looking for male-dominant BDSM,
Beyond Shame is competently written, has a more thoughtful story
than most, and has a female friendship that I fully enjoyed, which may
raise it above the pack.
Rating: 6 out of 10
With all the recent talk about running on Planet Debian I am proud to announce that I did a 10K run today. It took me just about an hour a pace which for Bubulle, Noel etc. is approximately equivalent to standing still but I managed to finish without collapsing in a puddle of sweat and shame, so I consider it an achievement.
In light of this, I have packaged and uploaded RDKit and Cinfony over the last weeks and also updated the Debichem task pages, introducing a Cheminformatics Task at the same time. I feel we still need at least tasks for Chemical Education (to expose e.g. Kalzium more prominently), and possibly Protein Docking and Crystallography. So if you have experience/opinions in these fields (or want to propose other fields), drop me a mail or contact us at debichem-devel@lists.alioth.debian.org.
This is a mental note really, since my certificates last two years and I ve always forgotten what to do about it.
Generate a new request: openssl req -new -key <keyfile> -out <csrfile> StartSSL throw away all properties of the request except the key, so any answers will do.
Re-use the request you sent last time (thanks Noel).
Get the certificate signed.
Dovecot expects a key in /etc/ssl/private/dovecot.pem and a certificate chain in /etc/ssl/certs/dovecot.pem. Build the chain, CERTIFICATE FIRST: cat <crt> sub_class2.pem ca.pem > /etc/ssl/certs/dovecot.pem
Reload Dovecot and test from somewhere remote: openssl s_client -connect <server>:imaps
Coffee time.
Lighttpd is basically the same, but additionally expects the key to be in the top of the certificate chain.
Allen Lesern w nsche ich ein Frohes Fest, fr hliche Weihnachten, viele Geschenke oder einfach nur einen sch nen 24.
Dezember!
To all readers: Merry Christmas, Buon Natale, Joyeux Noel, Vrolijk Kerstfeest or whatever you will celebrate these days
in your culture!
In a comment on my post about Designing Unsafe Cars [1] Noel said If you don t know how to make a surgery, you don t do it. If you don t know how to drive, don t drive. And if you don t know how to use a computer, don t expect anybody fix your disasters, trojans and viruses. Later he advocates using a taxi.
Now I agree about surgery apart from corner cases such as medical emergencies in remote places and large-scale disasters. I also agree that it s good to avoid driving if you aren t very good at it (that would be much better than the current fad of sub-standard drivers buying large 4WD vehicles).
But I don t think that people who lack computer skills should avoid using computers.
When cars were first invented everyone who owned one was either a mechanic or employed one. Driving a car often involved being well out of range of anyone else who might know how to fix it, so either the car owner or their chauffeur had to be able to fix almost any problem. As the car industry evolved the level of mechanical knowledge required to own and operate a car has steadily decreased. I expect that a significant portion of drivers don t know how to top up the oil or radiator water in their car and probably don t know what is the correct pressure for air in their tires. To a large extent I don t think this is a problem, owning a car involves regularly taking it to be serviced where professionals will (or at least should) check every aspect of the car that is likely to fail. If I used my windscreen-washer less frequently I could probably avoid opening the bonnet of the car between scheduled services!
When budgeting for car ownership you just have to include regularly spending a few hundred dollars to pay for an expert to find problems and fix them with of course the occasional large expense for when something big breaks.
When the computer industry matures I expect that the same practice will occur. Most people will buy computers and plan to spend small amounts of money regularly to pay people to maintain it. Currently most older people seem to plan to have a young relative take care of their PC for them essentially free mechanic services. The quality of such work will vary of course, and poorly designed OSs that are vulnerable to attack may require more support than can be provided for free.
Due to deficiencies in city design it is almost essential to drive a car in most parts of the US and Australia as opposed to countries such as the Netherlands where you can survive quite well without ever driving. When a service is essential it has to be usable by people who have little skill in that area. It would be good if driving wasn t necessary, I would be happy if I never drove a car again.
The need to use computers however will continue to increase. So we need to make them more available to users and to support users who can t disinfect computers etc. The only skill requirements for using a computer should be the ability to use a keyboard and a mouse!
This requires a new industry in supporting PCs. Geek Squad in the US [2] seems to be the organisation that is most known for this. I expect that there will be multiple companies competing for such work in every region in the near future, just as there are currently many companies competing for the business of servicing cars.
We need support for free software from such companies. Maybe existing free software companies such as Red Hat and Canonical can get into this business. One advantage of having such companies supporting software is that they would have a strong commercial incentive to avoid having it break unlike proprietary software vendors who have little incentive to do things right.
The next issue is the taxi analogy. Will software as a service with Google subsidising our use of their systems [3] take over any significant part of the market?
Of course the car analogy breaks down when it comes to privacy, no-one does anything remotely private in a taxi while lots of secret data is stored on a typical home computer. Google is already doing some impressive security development work which will lead towards low maintenance systems [4] as well as protecting the privacy of the users to the extent that you can trust whoever runs the servers.
My parents use their computer for reading email, browsing the web, and some basic wordprocessing and spreadsheet work. The mail is on my IMAP server so all I need is to have some way to store their office documents on a server and they will pretty much have a dataless workstation. Moving their collection of photos and videos of their friends and relatives to a server will be a problem, transferring multiple gigabytes of data on a cheap Australian Internet access plan is a problem.
Christmas holidays in France are not a good season for runners: too much champagne, foie gras, cheese, wine and food in general.
So, while visiting my mom and sister in the region of St-Etienne last week, I wanted to keep my sports pace to a sufficient level as we're now 3 months ahead from this marathon I've been crazy enough to apply for.
That went good: 3 days after my first run over 30km, my brother in law convinced me to enjoy the big snow fall in Le Bessat, the ski station of my young years, 30 minutes away from the city of St-Etienne.
That was the second time ever I'm doing croos-country skiing in skating technique. But, being supposedly used to skiing in general (20 years of ski are supposed to help), we went on the longest and hardest track: 16km and over 200m positive slope....which I completed in less than 2 hours, so a lot more than the same distance by running. Cross-country skiing in skating technique is awfully hard, particularly when you have no technique at all..:-))
To complete this, I went running for about 12 km on New Year, 3 hours after partying for New Year's Eve. Interesting way to eliminate the weight surplus..:-)
And, finally, today, I went out for a 19km run in the frozen country around my place (-8 degrees) for a wonderful discovery of woods covered with ice and the climbing of the highest "mountain" in the Paris area (280m height, still !) and a great view of the neighbourhood in white, under the sun. These are the joys of running in winter, really.
Allen Lesern w nsche ich ein Frohes Fest, fr hliche Weihnachten, viele Geschenke oder einfach nur einen sch nen 24.
Dezember!
To all readers: Merry Christmas, Buon Natale, Joyeux Noel, Vrolijk Kerstfeest or whatever you will celebrate these days
in your culture!
A research conducted by Noel A. Card at the Universities of North Carolina and Kansas, that appears in the September / October issue of journal Child Development, challenges the popular misconception that indirect aggression is a female form of aggression. The meta-analysis is based on 148 studies of aggression in children and adolescents in schools, involving on the whole about 74,000 children and adolescents.
Direct aggression is what we might call physical aggression, and indirect aggression includes covert behaviour designed to damage another individual’s social standing in his or her peer group. Based on the analysis, the researchers suggest that children who carry out one form of aggression may be inclined to carry out the other form. This is seen more in boys than in girls.
The popular myth that girls are more likely to be socially aggressive has been proven wrong by this analysis, even though it has persisted among teachers, parents, and even among researchers, probably because of social expectations and recent movies and books portraying girls as mean and socially aggressive.
They also found ties between both forms of aggression and adjustment problems. Direct aggression is related to problems like delinquency and ADHD-type symptoms, poor relationships with peers, and low prosocial behaviour such as helping and sharing, while indirect aggression is related to problems like depression and low self-esteem, as well as higher prosocial behaviour (perhaps because a child must use prosocial skills to encourage peers to exclude or gossip about others).
Thanks to the great work from, Sebastien Noel, the OSS4 package has made a great improvement ! An initial package has been commited to the SVN repository. It is not yet complete, but should work, provided you remove yourself the alsa modules (alsa force-unload, as root). I won't argue here about the sorry state of sound under linux, but you can read the links I already provided in the ITP for more details on this topic. Next to come: latest polishing, and then upload: yipee (...)
Some weeks ago I post about a spam contest where I participate.
This contest is now running for several weeks. (It will be finished
after 5 weeks). The aim is to get as most as possible spam to the
emailadress . (My is winnie@qsc218.credativ.com).
Atm I'm the second... I've ~140 spam mails and only 1 virus in
my mailbox Noel, who is on the first has ~150 spam mails and ~10
viruses in his mailbox :-S
The winner of this contest will get a free t-shirt (with a cool
text on it).
Yeah... it would rock if you can distribute this emailadress a
bit more, so that I recieves more spam Thanks!!
A few days ago, I just screwed the samba packages maintenance.
It's been quite some time since we were preparing Samba 3.2.0 packages. Upstream has not published a release version, only pre-releases. The release was planned for next week but will not happen as some last minutes issues have been found in pre-releases.
Anyway, we had ready packages for 3.2.0 pre-release 2....which were planed to go to experimental.
However, these packages were under preparation for quite a while, so when I finally agreed with Steve Langasek that it's OK to upload, I built and uploaded the packages. Then got a good laugh when discovering that I forgot "UNRELEASED" as target in debian.changelog.
It was late, I then "s/UNRELEASED/unstable" as I often do in such case....then uploaded...then forgot about the issue and went to something else.
The package went through NEW (it has a new binary package) and 1 or 2 days later quietly entered unstable.
...which I discovered only the next day, when it was way too late to remove from unstable something that was meant for experimental.
All this explains why samba packages now use an epoch...:-)
Things are back to normal now. Unstable has 1:3.0.28a-2 and experimental will hopefully have 3.2.0~pre2 soon.
Next week I go to the Samba annual conference. I'll probably spend some time hunting down some bugs in the package and discuss with upstream about some of the issues we have (old bugs, FHS patch, upstream's .deb packages). And maybe also get better ideas about Samba 3.2.x schedule, to be able to decide with Steve and Noel which release is the target for lenny: 3.0.28* or 3.2.x.
Here's, finally, the conclusion of my report from this year's CLT.
It's a bit belated since when I got home from Chemnitz I only had a
few hours to sleep and repack until I had to leave for Barcelona.
("Business trip", no blog material. It went well, though.) Anyway, I
am back now and finally have the time to finish this and upload my
slides and pictures.
The social event was great fun, there was again a really nice
buffet and we sat together with some people from team(ix). There was a quiz again,
this time the task was to find as many linux commands in a text as
possible. We even found a few more than the organisers had expected!
:) Everyone got a little chocolate Marx bust as a prize and the first
three places got an Uli Stein chocolate keyboard. (Pictures in the gallery)
I spent the biggest part of Sunday at the Debian booth or wandering
through the exhibition area. It was a bit more quiet than on Saturday,
probably also because of the social event and the Linux-Night that
took place at the same time.
The slides for my two talks are now on my talks page, the
pictures I took are in the gallery
and more pictures can be found at the
event's pictures collection.
PS: Dear fli4l guys, your picture is
here!
PPS: Thank
you, Noel!
The Chemnitzer Linuxtage event is over and like every year the event was very nice.
From my point of view it's one of the best organized and community driven events in Germany.
Sadly I just saw one talk (libfind) because most time I was busy with meeting all the people I can just see one time a year on this event and finding a way to allow dpkg to merge old and new configuration files.
This year I attended two booths, the one of my favorite live cd grml and the one of debian.
It was the first time for grml having a booth at the CLT and I think the feedback was quite good.
The debian booth was also very cool and well organized (thanks Noel) and I had alot of interesting discussions with different users.
One question which came up was why debian permits root logins in a default ssh installation. I had no answer for this question since I also think it's definitly a security issue. Elmar Hoffmann thought it could have to do with an easy way of scping files for root without using a user temporary.
If someone has an answer, let me know.
Hi from Chemnitz! As expected it's great here. As usual. :) My two talks
went really well. They were mostly freely improvised since I was kind of
slack regarding their preperation, but I got very positive feedback on both
and plan to expand them for future events.
There's still a lot of visitors walking around. The debian booth is well
visited with questions in all ranges, babelbox is running merily on the
demo machine in rotation with bb, which never ceases to fascinate people.
;)
My saturday was really busy. I walked over here around 8:30, had
breakfast and gave my first talk. After a two hour break I gave the other
one and ever since then I've been switching from one conversation to the
next without pauses. Most of these conversations were with "strangers" who
visited my talks and wanted to tell me about projects and ideas of their
own, their personal experiences with Linux and Free Software or give
further suggestions for my talks. I've really enjoyed these conversations,
though they got a bit tiring after a while since for some reason people
always catch me when walking somewhere, and so most of these long
conversations were held standing and my legs are pudding now.
In a few minutes (hopefully) the social will start and I hope it will be
as good as last year. I plan to take things a bit easier tomorrow, visit
other peoples booths, take some pictures and maybe even visit a talk or
two. The rest of this day will hopefully be spend having some more
inspiring conversations, enjoying good food and drink and continuing to try
to coax Noel into relinquishing to me his old Debian shirt, that he grew
out of. (Small Debian shirts are such a rare and precious good!)
Not that this city would be a very attractive one (in my humble opinion), but
they have one of the most interesting and well organized Linux events in
germany.
If you have nothing to do during the weekend (or need an excuse for not
having squashed any rc-bugs ;) get to Chemnitz; it's really worth it.
There'll be a Debian booth organized by Noel (Sorry, too lazy to dig out how
to get your accents in HTML), as well as other interesting booths. I'll give
a small workshop about debian package building. See you there!
Fun day today. Maj, Amita and I went up to the Christmas tree lot at Parc Lahaie on St. Joseph and St. Laurent. It was packed with people there for No l dans le Parc, a month-long Christmas festival held in two parks in Montreal. Of course, we had no idea it was going on before we got there.
Christmas tree lots in Quebec are a lot more festive than the businesslike lots in, say, California. There is often a pen full of farm animals -- like the Christmas manger, eh? -- that kids can look at and pet. Since it's often ass-cold, there's also usually a fireplace or a barrel fire. For some weird reason, all the lots in our neighborhood are in public parks, but that might have to do with a dearth of big parking lots in the Plateau.
But No l dans le Parc was even bigger than all that. When we arrived, there were two blues players in separate giant plastic globes hovering in the trees above the campfire. In two other (terrestrial) booths, a Quebec traditional music band was playing silently behind a glass window while a radio crew in the other booth broadcast them live. There was a concession stand serving bi re and vin chaud (of which we ordered two), and an open-air museum with fun stuff for kids.
We ended up hanging out for more than an hour. Amita June developed an intense fascination with the sheep in the petting zoo, and even after Papa had bought an 8' tree and tied it to the roof, she insisted on going back to the pen and saying goodbye one more time. The tree looks great in our living room -- it's almost scraping the ceiling, but it fills up its corner nicely.
tags: christmas treemontrealnoel dans le parcquebecchristmasamitajune
Lina and Jeremy's Xmas party
Even better tonight was our friends Lina and Jeremy's Christmas Party, at their house. Maj whipped up some steamed artichokes to take over, and I put together mixins for hot buttered rums, and we headed over to their great place in Little Italy.
We got there early and Lina had made mulled wine -- a big pot of it, based on the recipe from Clarence the Angel. Amita June headed off with Clea and Sylvie, two girls much older than her, and although she couldn't really communicate with them she followed along with what they were doing just fine. The under-10 crowd eventually settled around the TV, which was originally on Hockey Night in Canada but eventually switched over to a tape of Zoboomafoo.
So her Mama and I got to hang out with grownups for a change, which I at least was ill-equipped to do, but made a game attempt. Lots of nice people, including L and J's upstairs neighbor Annabelle, whose band The Wailin Jennys is doing pretty darn good lately. They're up for a couple slots in the Canadian Folk Music Awards tomorrow. Good for them.
I made a big batch of HBRs and they were quite a hit. It's such an easy recipe, I'll share it right here:
1 oz dark rum
1 tsp brown sugar
1 tsp butter
8 oz boiling water
Mix it all together in a coffee mug and serve when the butter's melted. Keeps you warm when you need it. We came home early, of course -- the baby's getting independent, but not that independent -- and now we're rresting from a long day.
tags: linajeremyxmas partyannabellethe wailin jennys
Wikitravel RSS
So, I know this sounds crazy, but we've never really had much of an RSS presence for Wikitravel. We've got an RSS feed for Recent Changes, of course, as does every MediaWiki site, but never anything else.
But I was talking to Jack Herrick of wikiHow recently, and he was telling me that their Daily Howto RSS feed is one of their biggest vectors of people coming into the site. Wikitravellers make updated news and information on our Main Page all the time, so I figure it'd be useful to make an RSS feed of new stuff from Wikitravel, too.
So I've started scraping the frequently-updated parts of the site to make them available through a Wikitravel News feed. It includes the strange-travel trivia from Wikitravel:Discover and the Travel news info, too.
There's been a lot of work in it -- making feeds out of wiki pages requires some assumptions and creative markup. But I'm getting closer, and I think the lessons I'm learning with our English version will help making RSS feeds for the other language versions easier. I'll be adding in more features for English, too, as I learn how to scrape them better.
tags: wikitravelrsswikihowtravel newstriviadaily howto
co2mon.nz currently uses monitors based on Oliver Seiler s open source design which I am personally building. This post describes my exploration of how to achieve production of a CO2 monitor that could enable the growth of co2mon.nz.
I started out trying to use the EasyEDA/OSHWLab ecosystem thinking the tight integration with JLCPCB s assembly services would be a benefit, but the web interface was too clunky and limiting and I quickly got frustrated. KiCad proved to be a much more pleasant and capable tool for the job.
The reference design in the ESP32 datasheet (p28) and USB-C power supply examples from blnlabs were particularly helpful alongside the KiCad documentation and the example of the existing monitor in completing this step (click the image to enlarge).
Taking all of these factors into account I ended up with a square PCB containing a cutout in the top right so that the ESP32 antenna can sit within the overall square outline while still meeting its design requirements. The SCD40 and BME680 sit in the top left corner, near the edges for good airflow and far away from the SHT30 temperature sensor in the bottom left corner. The LEDs I placed in a horizontal row across the center of the board, the LCD in the bottom right, a push button on the right-hand side and the USB-C socket in the center at the bottom.
Once the components are placed, the next big task is to route the traces (aka wires) between the components on the board such that all the required electrical connections are made without any unintended connections (aka shorts) being created. This is a fun constraint solving/optimisation challenge and takes on an almost artistic aspect with other PCB designers often having strong opinions on which layout is best. The majority of the traces and routing for this board were able to be placed on the top layer of the PCB, but I also made use of the back layer for a few traces to help avoid conflicts and deal with places where different traces needed to cross each other. It s easy to see how this step would be much more challenging and time consuming on a larger and more complex PCB design.
The final touches were to add some debugging breakouts for the serial and JTAG ports on the ESP32-S3 and a logo and various other helpful text on the silkscreen layer that will be printed on the PCB so it looks nice.
The final surprise in the assembly process was the concept of edge rails, additional PCB material that is needed on either side of the board to help with feeding it through the assembly machine in the correct position. These can be added automatically by JLCPCB and have to be snapped off after the completed boards are received. I hadn t heard about these before and I was a little worried that they d interfere or get in the way of either the antenna cut-out at the top of the board, or the switch on the right hand side as it overhangs the edge so it can sit flush with the case.
In the end there was no issue with the edge rails. The switch was placed hanging over them without issue and snapping them off once the boards arrived was a trivial 30s job using a vice to hold the edge rail and then gently tipping the board over until it snapped off - the interface between the board and the rails while solid looking has obviously been scored or perforated in some way during the production process so the edge breaks cleanly and smoothly. Magic!
The process was amazingly quick with the completed PCBs (picture above) arriving within 7 days of the order being placed and looking amazing.
As a result I ended up completely flipping the design such that the front panel is a single piece of plastic that also encompasses the walls of the case and contains appropriate mounting stakes for both the screen and the main PCB.
Getting to this design hugely simplified the assembly process. Starting with an empty case lying face down on a bench, the LCD screen is pushed onto the mounting poles and sits flush with the cover of the case - easily achieved without the main PCB yet in place.
Next, the main PCB is gently lowered into the case facing downwards and sits on the mounting pole in each corner with the pins for the LCD just protruding through the appropriate holes in the PCB ready to be quickly soldered into place (this took significant iteration and tuning of dimensions/positioning to achieve!).
Finally, a back panel can be attached which holds the PCB in place and uses cantilever snap joints to click on to the rest of the case.
Overall the design is a huge improvement over the previous case which required screws and spacers to position the PCB and cover relative to the rest of the case, with the spacers and screws being particularly fiddly to work with.
The major concern I had with the new design was that the mount to attach the monitor to the wall has moved from being attached to the main case and components directly to needing to be on the removable back panel - if the clips holding this panel to the case fail the core part of the monitor will fall off the wall which would not be good. To guard against this I ve doubled the size and number of clips at the top of the case (which bears the weight) and the result seems very robust in my testing. To completely assemble a monitor, including the soldering step takes me about 2-3 minutes individually, and would be even quicker if working in batches.
I tried a variety of filament colours, but settled on a transparent filament which once combined in the necessary layers to form the case is not actually transparent like perspex is, but provides a nice translucent medium which achieves the goal of having the light colour visible without exposing all of the circuit board detail. There s room for future improvement in the positioning of the LEDs on the circuit board to provide a more even distribution of light across the case but overall I really like the way the completed monitor ends up looking.
The goal of having a CO2 monitor which I can outsource the vast majority of production of is as close to being met as I think is possible without undertaking the final proof of placing a large order. I ve satisfied myself that each step is feasible and that the final assembly process is quick, easy and well below the level of effort and time it was taking me to produce the original monitors.
Cost wise it s also a huge win, primarily in terms of the time taken, but also in the raw components - currently the five prototypes I ordered and built are on par with the component cost of the original CO2 monitor, but this will drop further with larger orders due to price breaks and amortisation of the setup and shipping expenses across more monitors.
This project has also given me a much better appreciation for how much I m only just scratching the surface of the potential complexities and challenges in producing a hardware product of this type.
I m reasonably confident I could successfully produce a few hundred and maybe even a few thousand monitors using this approach, but it s also clear that getting beyond that point is and would be a whole further level of effort and learning.
Hardware is hard work. That s not news to anyone, including me, but there is something to be said for experiencing the process first hand to make the reality of what s required real.
The PCB and case designs are both shared and can be found at https://github.com/co2monnz/co2monitor-pcb and https://github.com/co2monnz/cad, feedback and suggestions welcome!
Taking all of these factors into account I ended up with a square PCB containing a cutout in the top right so that the ESP32 antenna can sit within the overall square outline while still meeting its design requirements. The SCD40 and BME680 sit in the top left corner, near the edges for good airflow and far away from the SHT30 temperature sensor in the bottom left corner. The LEDs I placed in a horizontal row across the center of the board, the LCD in the bottom right, a push button on the right-hand side and the USB-C socket in the center at the bottom.
Once the components are placed, the next big task is to route the traces (aka wires) between the components on the board such that all the required electrical connections are made without any unintended connections (aka shorts) being created. This is a fun constraint solving/optimisation challenge and takes on an almost artistic aspect with other PCB designers often having strong opinions on which layout is best. The majority of the traces and routing for this board were able to be placed on the top layer of the PCB, but I also made use of the back layer for a few traces to help avoid conflicts and deal with places where different traces needed to cross each other. It s easy to see how this step would be much more challenging and time consuming on a larger and more complex PCB design.
The final touches were to add some debugging breakouts for the serial and JTAG ports on the ESP32-S3 and a logo and various other helpful text on the silkscreen layer that will be printed on the PCB so it looks nice.
I tried a variety of filament colours, but settled on a transparent filament which once combined in the necessary layers to form the case is not actually transparent like perspex is, but provides a nice translucent medium which achieves the goal of having the light colour visible without exposing all of the circuit board detail. There s room for future improvement in the positioning of the LEDs on the circuit board to provide a more even distribution of light across the case but overall I really like the way the completed monitor ends up looking.
With all the recent talk about running on 
I am currently sitting in the train to Goslar, where the 
Christmas holidays in France are not a good season for runners: too much champagne, foie gras, cheese, wine and food in general.
So, while visiting my mom and sister in the region of St-Etienne last week, I wanted to keep my sports pace to a sufficient level as we're now 3 months ahead from this marathon I've been crazy enough to apply for.
That went good: 
A 
Thanks to the great work from, Sebastien Noel, the OSS4 package has made a great improvement ! An initial package has been commited to the SVN repository. It is not yet complete, but should work, provided you remove yourself the alsa modules (alsa force-unload, as root). I won't argue here about the sorry state of sound under linux, but you can read the links I already provided in the ITP for more details on this topic. Next to come: latest polishing, and then upload: yipee (...)
Thanks!!