Today’s episode will be a short one, it’ll become clear halfway down…

This is a little bargain LED flashlight, nothing to it really:

Three AAA (not AA) cells, a toggle button, 24 + 4 white LEDs, and that’s it. Press the button once, and the 4 LEDs on the side turn on, press again to light the 24 on the top, and again to turn it off.

Quite a bright light BTW. The 4 LEDs draw 190 mA, with 16 it rises to 270 mA. That’s perhaps 4 hours of use with 16 LEDs before the batteries run out.

The circuit is as ridiculously simple as can be – one 4.7 Ω resistor and a switch:

That “metal” reflector is actually plastic with a chrome finish. The PCB is one-sided, no doubt to lower the cost:

(it won’t take much bending to create a short with that top wire!)

Using Ohm’s law (V = I x R), we can deduce that the LED’s forward voltage is 4.5 – X = 0.190 x 4.7 – in other words, X = 4.5 – 0.190 x 4.7 = 3.6V. Note that the light intensity will vary considerably with battery voltage and that this lamp won’t work at all with 3 AAA EneLoop batteries which only supply 1.2V to 1.3V when fully charged.

The reason I’m opening up this trivial little gadget is not to marvel at the deep electronic engineering that went into it, but to show how custom plastics and a custom case makes something quite practical and nice to the touch. The top and bottom have a rubbery feel to them. The bottom has a little plastic hook in it, which can be folded out.

The bigger news today is a bit of a mess, unfortunately.

Last night I decided to upgrade the JeeLabs server from Mac OSX 10.7.3 to 10.7.4 – that update had been out for a few days, worked fine on two other machines here, so it seemed safe to apply the update to the server as well.

It failed.

This server is connected via wired Ethernet, and I usually only look at the GUI via a VNC-like “Screen Sharing” mechanism built into Mac OSX. It works well, because that connection is re-established even when the machine is in an exclusive “Updating…” mode, so you get to track progress even while the system is busy replacing some of its own bits and pieces. No screen needed, even though part of admin interface sometimes uses the GUI.

Last night, the server failed to come back online. Which is a major hassle, because then I have to move it to another spot to hook up a mouse, keyboard, and monitor to see what’s going on. Never happened before.

Trouble is (probably), that I turned the darn thing off forcefully. I knew that all the VM’s had been properly shut down, and I heard the characteristic reboot “pling”, so I thought it was waiting for a GUI response… or something.

Then the trouble started. Hooked it up, did a restart: no go. So I restarted it in recovery mode, and did a disk check/repair of all the disks. Guess what: the startup disk with all VM’s could not be repaired… whoops!

Time to kick my backup strategy in gear. I have two in place: local hourly Time Machine backups to a second drive, and daily backups for all VM’s to the cloud.

To make a very long night story short: the local hourly backups are fine, but they do not include the VM’s (whole-file backups of a VM disk every hour is not really practical). And the daily backups? Well, they are indeed all there – I can get any day in the past 3 months back, for any of the 4 VM’s. Awesome.

But Turnkey Linux does things a bit differently. Very clever in fact: it only backs up the minimum. The Linux Debian packages for example: these are not backed up, but re-installed from some other source. The rest is a well thought-out mix of full and incremental backups, and it all works just as expected.

Except that my VM’s are about two years old now, and no longer the latest base images used by Turnkey Linux. No problem, they say: you can get the latest, and then recover your own stuff on top of that.

So I spent about 6 hours trying to work out how to get my VM’s back up from the Amazon S3 storage. No joy. I can see all the files being restored, but the result is not a working VM. At some point, package installs & updates hang, with either udev restart problems or bootdisk image generation problems.

And now the crazy bit: the JeeLabs weblog + forum + café sites are all back up again (phew!). I restored from Time Machine to a freshly freed disk partition, and restarted the Mac – it’s alive! Right now, the server is running from the new disk partition, but with the 4 VM disk images still on the damaged partition. So apparently they did not get any damage, although the Mac file system structure on that disk seems to be hosed.

I’ll spend some time thinking about how to clean up this mess, and how to avoid it in the future. The good news is that I lost no data – just a lot of time and some hair. Yikes … this really was uncomfortably close to the edge!

The moral: test the backup strategy regularly. It can still break, even when not changing anything!

Update – all systems are “go” again.

It all started on October 25th in 2008, with a weblog post about – quite appropriately – the Arduino.

Then it took a few more months to evolve into a daily habit, and yet another few months to set up a shop, but apart from that it has all remained more or less the same ever since.

You might have been following this from the start, and you might even have been going through the long list of daily posts later, but there you have it – a personal account of my adventures in the world of Physical Computing. If anything, these years have been the source of immense inspiration and delight. I’ve been able to re-connect to my inner geek, or rather: my inner ever-curious and joyful child. And to so many like-minded souls – thank you.

“Standing on the shoulder of giants” is a bit over-used as a phrase, but it really does apply when it comes to technology and engineering. What we can do today is only possible because many generations of tinkerers, inventors, and researchers before us have created the foundations and the tools on which we can build today. It feels silly even to try and list them – such a list would be virtually endless.

I’m not a technocrat. I think our IT world has done its share to rob people of numerous meaningful and competence-building jobs, and to introduce new mind-numbing and RSI-inducing repetitive tasks. Our (Western) societies have become de-humanized as more and more screens take over in the most unexpected workplaces, and our car trips and train rides are turning us into very selectively-social beings, reserving our emotions but even our respect and courtesy for our families and the people we choose as our friends. Technology’s impact on daily life is a pretty horrible mess, if you ask me.

But what drives me, are the passion and the creativity and the excitement in the field of technology. Not for the sake of technology, but because that’s one of the major domains where cognition and rationality have free reign. You can learn (and reason) all about history, medicine, psychology, or you can invent (and reason about) things which do new things, be it electrical, mechanical, biological, informational, or otherwise. Technology as a source of boundless evolution and innovation is breath-taking, we “merely” have to tap it and put it to good use.

And what thrills me most is not what I can do in that direction, but what others have done in the past and are still doing every day. Learning about all that existing technology around us is like looking into the minds of the persons who came up with all that stuff, feeling their struggles, their puzzles, and ultimately the solutions they came up with. I’m in awe of all the cleverness that has emerged before us, and even more in awe of the thought that this will no doubt go on forever.

It’s really all about nurturing curiosity, asking questions, and solving the puzzles they bring to the surface:

I have no special talents. I am only passionately curious. — Albert Einstein

Here’s the good news: we all have that ability. We all came into the world the same way. We can all be explorers.

If you start doing this early on in life and hold onto it, you’ll never be hungry and you’ll never get bored. And if you didn’t have that opportunity back then: nothing of substance prevents you from starting today!

We live in amazing times. Ubiquitous internet and access to knowledge. Open source Physical Computing. Online communities with a common language. This weblog is simply my way of reciprocating all these incredible gifts.

Free online university classes for everyone.

It’s a phenominally exciting initiative, second only to the Khan Academy, if you ask me:

The idea: great video lectures plus exercises to let anyone with (good) internet access learn some major topic really well. You have to be fluent in English, evidently, but apart from that the courses seem to be designed to give the broadest possible group of people access to this new form of – literally! – world-class education.

These guys are serious. With a pool of well-known researchers and teachers and set up to scale massively (the class on Artificial Intelligence which led to all this had over 160,000 people signed up).

For some background info about this project, see these Hack Education and Reuters articles.

The format is slightly different from the Khan Academy in that the courses start on a fixed date and have a fixed duration. So you really have to “sign up” for class if you want to benefit from what they have to offer.

As it so happens, these classes start tomorrow, Monday, April 16th and they will last for 7 weeks.

It looks like there will be a bunch of videos each week, plus some homework assignments, which you can then follow whenever you have time that week. You can enroll in multiple courses, but I’m sure they will be repeated at a later date, so it’s probably best to just pick what feels like a good match right now.

What can I say? IMO, this is a unique chance to learn about modern software programming on many levels. Whether you’ve never built any software or whether you are curious about how some really sophisticated problems can be solved, these six courses cover a breathtaking range of topics.

I don’t know how these courses will turn out, but I do know about some of the names involved, and frankly, I’d have loved to have this sort of access when starting out in programming.

FWIW, out of curiosity, I’ve signed up for CS101. What a nice birthday present.

There has never been a better time to learn than now. This world will never be the same again.

It’s a bit radical and unexpected, but there is no way around it. This weblog is “driven by passion”, as you will probably know, and the crazy bit is that there’s just too much going on here to keep things going smoothly. I’ve been running behind on shop fulfillment again, and I’ve been running behind even more on answering emails and with helping out on the forum. First thing I hope this will do, is to let me catch up and regain my footing.

In sharp contrast to last year’s emergency stop, this time it’s not so much lack of ideas or lack of energy, but lack of clear focus and direction. The stories I would love to tell need more time – diving into various aspects of physical computing in considerably more depth and detail than what’s been happening on the weblog lately. And it’s not happening because the daily bite-sized cycle is chopping up my attention (even at times when I have enough weblog posts queued up for many days on end – go figure!). And maybe it’s also a hill climbing issue.

For an interesting insight about attention, see Paul Graham’s essay titled Maker’s Schedule, Manager’s Schedule.

I’ve updated the alphabetical and chronological indexes to all the posts on this weblog, to give you something to go through for the coming weeks. It’s a stopgap measure, but it’ll just have to do – and there should be enough to keep you interested and hopefully also pique your interest and keep you excited in the month ahead.

The difference with last year, is that I’m putting a precise cap on the duration of this “outage”: 30 days from now. That’s when this weblog will resume, probably with some announcements and adjustments to its style and format.

Talk to you one month from now!

PS. If you want to learn about electricity, then there are numerous resources on the web. Let me single out one: a 50-minute video by Walter Lewin at MIT about batteries and power (lecture 10 on this page). You can get a deep understanding of what a battery is, why its internal resistance matters, what power is, how heat comes out, what shorting a battery does, and even sparks. It’s a fantastic presentation, and the video was just picked at random!

As my contribution to slowing down, I’d like to encourage everyone interested in Computing Stuff tied to the Physical World to deepen your understanding and broaden your experience. So allow me to introduce a little tinkering kit, for those of you who are into ATmega’s and wireless stuff – the JeeNode Block:

This is a recent experiment to fool around with the JeeNode form factor, as a way to create a little self-contained unit which needs no wires to operate. I’m using these blocks to try things out on my desktop (you know, the real physical one), without turning it into a huge spaghetti bowl of power supply wires, USB cables, and test hookups.

It’s basically just a JeeNode, but with a different layout (and RFM12B’s “INT” pin reallocated from PD2 to PB0):

It’s exactly the right size to support simple low-cost 5×7 cm prototyping boards (lets not call ‘em “shields”, ok?):

The three headers at the bottom are: 8 digital I/O pins, 4 power pins, and 6 analog I/O pins. The two headers at the top are JeeNode ports 1 and 2. There’s a reset button, an LED, and an FTDI header for uploading new code. The 3x AA battery pack will power the whole thing at 3.6 .. 4.5 V, depending on the type of batteries used. There’s a regulator on board to run at 3.3V, as with all the other JeeNode variants.

Note that this is not a product in the shop. It’s just an exploration by yours truly. And it’s also a one-time offer:

As special encouragement to “start 2012 by tinkering”, I’ll add a JeeNode Block PCB and a prototype board for free to the first three dozen or so people who order a JeeNode from the shop and ask for it. You can then simply re-use all the JeeNode parts for this board (except for the JeeNode’s PCB), since everything is more or less the same. A few missing components will also be included: extra headers, an LED, and the reset button. To take advantage of this offer, select “JeeNode w/ extra Block” from the pop-up list on the order page. Note: this offer is limited to at most one Block per person.

If you come up with a neat project for the JeeNode Block, I encourage you to share your invention on the forum.

Happy 2012. With 5000 hours to discover your passion, extend your knowledge, and unleash your creativity.

Anyway, it turns out that there is now a “customer login” option, which I activated a few days ago. What that means is that whenever you shop at JeeLabs, you now get a choice when checking out your order:

What that really means, is that you won’t have to re-enter your shipping details over and over again if you decide to come back for more. And judging from the info in Shopify, that’s about a third of all JeeLabs customers. I am very proud of that fact BTW, because in my view a return customer is someone who is genuinely satisfied with what he/she got the first time around. It feels good to be able to follow up.

If you don’t want to leave this sort of info on the Shopify servers, please keep in mind that the only difference is that you get to pick a password for re-using what you’ll need to enter anyway.

In case you’re worried that this information is going to be used (by me or anyone else), for anything but order fulfillment: don’t be. I’m probably far more extreme in my position than you on privacy. I do not track personal details. The internet is a nightmare in that respect as it is. I Really Do Not Track, nor keep logs, nor “forget” to remove logs. I don’t do Google Analytics. I don’t have the Shopify “stats” option. I don’t “visualize” web accesses. All I keep are recent activity logs of my own servers, to be able to figure out problems when needed.

Life’s too short for lots of things – and that includes feeding ego’s and spying on people, IMO :)

But that doesn’t mean you have to suffer and re-enter the same info over and over in the JeeLabs shop, eh?

If you’re into this sort of thing, consider joining. It’s bound to be fun, and it’ll be great to meet up in person :)

(Groningen brings up lots of memories, I grew up there – most of my primary school time anyway)

Soooo… see you there?

One of the major changes is to move all JeeLabs open source software to GitHub:

The main reason for doing this, is that it makes it much easier for anyone to make changes to the code, regardless of whether these are changes for personal use or changes which you’d like to see applied to the JeeLabs codebase.

For the upcoming Arduino IDE 1.0 release (which appears to break lots of 0022 projects), I’ve moved and converted a couple of JeeLabs libraries so far:

• Ports and RF12 have been merged into a single new library called JeeLib
• the EtherCard and GLCDlib libraries have been moved without name change
• all *.pde files have been renamed to *.ino, the new 1.0 IDE filename extension
• references to WProgram.h have been changed to Arduino.h
• the return type of the write() virtual function has been adjusted
• some (char) casts were needed for byte to fix unintended hex conversion

If you run into any other issues while using this code with the new Arduino IDE 1.0beta2, let me know.

So what does all this mean for you, working with the Arduino IDE and these JeeLabs libraries?

Well, first of all: if you’re using IDE 0022, there’s no need to change anything. The new code on GitHub is only for the next IDE release. The subversion repositories and ZIP archives on the libraries page in the Café will remain as is until at least the end of this year.

New development by yours truly will take place on GitHub, however. This applies to all embedded software as well as the JeeMon/JeeRev stuff.

The new JeeLib should make it easier to use Ports and RF12 stuff – just use #include <JeeLib.h>.

Note that you don’t need to sign up with GitHub to view or download any of the JeeLabs software. The code stored there is public, and can be used by anyone. Just follow the zip or tar links in the README section at the bottom of the project pages, or use git to “clone” a repository.

To follow all my changes on GitHub, you can use this RSS feed. To follow just the changes to JeeLib in slightly more detail, this feed should do the trick.

One of the features provided by GitHub is “Issue Tracking”, i.e. the ability to file bugs, comment on them, and see what has been reported and which ones are still open. This too is open to anyone, but you have to be signed up and logged in to GitHub to submit issues or discuss them.

For questions and support, please continue to use the JeeLabs forum as before. But if you’re really pretty sure there’s a bug in there, you’re welcome to use the issue trackers (as you know, Mr Murphy and me tend to sprinkle bugs around from time to time, just to keep y’all sharp and busy ;)

And if you’d like to suggest a change, consider forking the code on GitHub and submitting a “pull request”. This is GitHub-speak for submitting patches. Small changes (even multiple ones) are more likely to go in than one big sweeping request to change everything. I’m open for suggestions (in fact, I’ve got a couple of patches from people still waiting to be applied), but please do keep in mind that code changes often imply doc changes, as well as making sure nothing breaks under various scenarios.

All in all, I hope that GitHub will help us all keep better track of all the latest changes to the software, work together more actively to fix bugs and add more functionality. I haven’t heard of GitHub ever going offline, but if it ever does, I’ll make sure that the latest code is also available from the JeeLabs servers as backup.

Update – Here’s an excellent article on how to collaborate via Git and GitHub.

But it’s only fitting that today is also a great time to celebrate. Because this weblog has reached…

That’s right. Eight hundred articles on this weblog, published on a daily basis – at midnight Central European Time. About all the fun in physical computing and the electronics, hardware, software, and mechanics surrounding it – collected as a stream of notes describing my adventures in this geeky world of techno-babble.

The posts on this daily JeeLabs Weblog are – by definition – organized as a timeline. Some of it will inevitably be wildly obsolete by now, other parts are timeless and still useful, but if you didn’t tag along from the beginning in 2008, then it might all be somewhat overwhelming – or ridiculously frustrating, depending on your expectations.

There are a few ways to find your way around here. First of all, there are six categories (some of them quite large by now): AVR, Hardware, Musings, News, Software, and the catch-all Uncategorized. A somewhat more fine-grained structure is available through 28 “tags”, shown at the top of each post. There’s an updated listing of them on the intro page.

Another approach to finding your way around here, is to use the Search box at the bottom right of each page. It works quite well, but don’t search too broadly or you’ll get a result with hundreds of posts.

The third place to look for interesting posts is on the “Café“, and especially the pages in the hardware wiki, many of which have a Related Weblog Posts section at the end. I’ve tried to add links to new pages there whenever I could, although there’s still lots of room for improvement.

And last but not least, there’s the forum area, which is getting more and more traffic these days, so it could be a good place to search and ask questions. I tend to participate at least once a day (although quite a bit less in the two months ahead).

If shopping for JeeNodes and other JeeStuff is your kind of thing, don’t forget that the shop will close for one month, starting two weeks from now, and that there’s a discount / sale right now for current customers and contributors. See this page for all the details.

I’d like to thank everyone who in some form or other voiced their appreciation and encouraged me to push further. Techie as it all may be, this weblog is still about people, creativity, and shared passions. Because without all that, there is no point.

Scattered over the coming two months, Liesbeth and I will break away and travel in Europe for a while, and I’ll fill in the rest of this long summer by relaxing, learning, tinkering, experimenting, working on top-secret stuff, and cooking up all sorts of crazy hardware and software for future JeeLabs projects and products.

These daily weblog posts will resume on September 1st.

Until then, for your entertainment, a tale of two worlds: Splitscreen.

Enjoy!
-jcw

Update – Full alphabetical and chronological index.

1. The JeeLabs online shop will be closed from July 16 to August 15, 2011.

2. The JeeLabs daily weblog will be on hold from July 1st to August 31st.

3. Sale!

Each order will be checked, if I can’t figure it out I’ll contact you by email (this may add to the delay).

Update – Similar conditions now also apply for JeeLabs products in the Modern Device – same discount code!