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!

The benefit of doing everything yourself, is that you can make things work exactly as you want them.

The drawback of doing everything yourself, is that you have to do everything yourself…

Having become pretty independent in my work areas, my hobbies, and my income streams over the years, I know all about those trade-offs. Or at least I think I know about most aspects of this DIY-vs-outsourcing range.

It’s a bit like trying to stay on your feet with a floor covered with marbles…

Example: I used to rent a web server (a real physical one, with full root access and Linux on it). No worries about hardware outages or connectivity details. Being housed at an ISP with thousands of servers, means they’ll have round-the-clock watchdogs and support staff, and will jump into action the minute something is seriously wrong.

At the same time, I had total control over the web server software and operating system configuration. With a Linux distribution such as Debian, maintenance was delightfully simple (“apt-get update && apt-get upgrade”).

The flip side is that I had to choose and configure a web server (“lighty” / lighttpd at the time), and technologies to create dynamic database-driven websites (I built my own back then, based on Metakit – my own database).

Did it work? Sure. Did it evolve? Nope. Too busy. Didn’t want to risk breaking anything.

Only thing that setup did was track security updates (automatically). I had two break-ins over the 10 years that this went on. Learned more about rootkits than I care about (they’re evolving to amazingly sophisticated levels).

Did I learn a lot? You bet. And some of that knowledge is priceless and timeless. Big, big benefit.

But I also had to learn lots of stuff I really care very little about. For me, network routing, package installation dependencies, mail server configuration, and lighttpd configuration were a waste of time. The latter because lighttpd wasn’t really kept up to date very actively by its developer(s). Other options became more practical, meaning that all that lighttpd-specific knowledge is now useless to me.

The story is repeating itself right now. Redmine, which I use on http://jeelabs.net/ is not up to date, because I haven’t found a simple upgrade path. The difference is that it’s not just me not updating my stuff, I now have the same stagnant state with stuff from others. So what’s the point of Redmine? As far as I’m concerned, it’s a dead end (luckily, everything in there is stored in Markdown format – a solid long-term standard which I also use for the forum and the weblog).

With the forum, running on Drupal, it’s different again. Module updates are automated more or less, so I tend to track them from time to time. But Drupal itself is a little harder to update. And sure enough, it’s falling behind… With Drupal, I’m also running into not being knowledgeable enough to put it to really good use.

But the reason for writing this post is a different one – see the message at the top.

For the web shop, I use the Shopify web store service. They have the servers (at Rackspace – very good ops, I’ve used them for a couple of years). And Shopify develop and run the web store software (using Ruby on Rails).

They take care of dealing with nasty things such as possible DoS attacks, heavy data security, financial gateway interfaces – lots of important issues I no longer need to worry about. So far so good.

But they have their own agenda:

• some things don’t change, and that’s good: it works, the shop is operational
• some things don’t change, but that’s bad: years have gone by, and they still haven’t got a clue about VAT
• some things change, and that’s good: improvements to the service, new features for customers
• some things change, but that’s bad: they change their API and their XML data structures

That last one is what bites me now. I created a little scripted setup whereby I always pull information about orders from their shop database, to fill my database here with all the details, so I can generate paper invoices, and do the fulfillment of orders here. Doing this here was necessary to be able to do the Value Added Tax thing properly, as required by law and as my accountant wants it, of course.

So to summarize, the choices are:

1. do everything yourself (and pay in time)
2. outsource everything (and pay in money)
3. choose a mix (and deal with the interface changes)

Everything is a trade-off, of course. In my case, I’m moving more and more to #1 as far as operational choices are concerned (own server, own fiber connection), and #2 as far as day-to-day software use is concerned (solid, but actively developed open source software, and Apple hardware + Mac OSX for my main workplaces). These choices are optimal for me, in terms of cost and stability.

The choice to host my own servers was made a lot simpler because I’m running VM’s for the different sites, built from ready-to-run images from TurnKey Linux. What makes them (and others, like Bitnami) different, is that all VMs are automatically backed up to the cloud (Amazon S3 in my case). The way TKL does this is really clever, reducing the amount of data in incremental backups, even for all the records stored in MySQL. So not only are my VM’s pre-configured and run out of the box, they automatically self-update and they automatically self-backup – if anything goes completely wrong, I can switch to cloud-based instances and be up and running again in no time.

TurnKey Linux is an example of using third-party stuff to side-step (and in fact avoid) a massive amount of effort, while retaining maximum operational flexibiity. My Amazon S3 bill is a whopping $1.01 per month…

But the web shop setup at Shopify is far from optimal. It was supposed to be choice #2, but ended up being #3 due to the mismatch between what I need (a European shop with correct VAT handling) and what they offer (flashy stuff, aimed at the masses). In hindsight, it was a bad choice, but I really don’t want to do this myself.

Oh well, I’ll suffer the consequences – will fix my scripts and get everything going again by next Monday!

PS. My little presentation yesterday at HackersNL #5 can be found here (PDF) – for those who read Dutch.

This is a German site which supports direct bank-to-bank transfers. Looks like it’s working in 5 countries:

• Austria
• Belgium
• Germany
• Netherlands
• Switzerland

I can’t find a trace of UK or Italy in the setup, even though it’s mentioned on their web site. My impression is that this service is still very young – the “Payment Network AG” company behind this was registered last October. But the good news is that their support is responsive and effective, by email as well as by phone.

One benefit for customers is speed: I get immediate notification, avoiding the usual 1..3 day delay normally involved with bank transfers. The other benefit is convenience, since you can complete the payment as part of the order, instead of having to switch to your online bank account and manually copy all the relevant info.

The benefit for me is lower cost: a third of what PayPal charges (it does add up: VAT, payment/bank/shop fees).

The thing with this sort of service, is that it’s very hard for me to get an impression of how well it works in practice. I did a “test payment” while setting things up, but that’s a weak approximation of the whole process when using it for real, and I can only do a more realistic test with my own country and my own bank account.

So if you ever feel an uncontrollable urge to order something from the JeeLabs web shop (yeah, I know, it’s unlikely) and live in one of the above-mentioned countries, then please feel free to give this a go:

The name is in German (Sofort Überweisung), but the page will be in English by default (all pages are available in multiple languages by clicking on the flag – top right).

Please feel free to email me with anything odd (or neat) which comes up, especially if it doesn’t work as expected of course. I can easily cancel an entire transaction if things get really out of hand.

But with a little luck, life will simply have become one notch simpler with this new option – for everyone!

Reading has changed a lot these past few decades. I used to devour books in the library and subscribe to lots of magazines. As a kid, when visiting New York one summer, I spent weeks on the floors of the the New York Public Library – because they had all the back issues of Scientific American and you could read as much as you want!

The thing with SciAm, is that it had a column every month, called The Amateur Scientist – which, in hindsight, was really the ultimate “maker” breeding ground. I don’t think I ever built anything described in it (’cause teenagers don’t have any money), but that did not diminish the fun and learning experience one bit.

A side-effect of all this was that my environment filled itself with books, papers, magazines, and articles.

And although the human mind is incredibly good at remembering where things are, by association, and particularly by how it looks and its location, there comes a point when ya’ can’t find that one friggin’ article back. With computers, things quickly got (much!) worse… no more clues as to which book (file!) is large, which one looks worn-out, what the books (files!) around it look like, or to leaf through it quickly to locate a section (bits!) by its visual appearance.

Besides, most magazines and books are really just meant to be read once. You digest the info, learn from it, and never look back. It seems silly to buy them in dead-tree form, and continuously add more bookshelves for them.

So I started to get more and more books, articles, and magazines in PDF form. They were easy to store, could be browsed as well as searched via keywords. I bought – and still buy – lots of books that way. My favorite PDF shop (for programming-related books) is probably the Pragmatic Programmers – nice collection, well-written and good-looking books, and you get update notifications when books get revised (a key benefit of the electronic format).

My collection of PDFs is growing fast. Purchased as well as downloaded. And now also lots of electronics datasheets.

This reached a point where I decided that I wanted to get rid of the paper stuff, at least for normal technical books to which I have no particular emotional attachment. So I got one of these a couple of years ago:

That’s a Fuijistu ScanSnap S510M document scanner. There are newer models now, for Mac and PC. The thing about this scanner is that it’s surprisingly effective. It scans quickly, and does both sides of the page at the same time. But the real gem is the supporting software. It knows what’s color and what’s black and white, it knows what’s up and what’s down, it knows what’s portrait and what’s landscape, and it it knows how to start up the software when you press the big button on the front. Best of all, it comes with OCR software which places the recognized text inside the PDF, and puts it there invisibly – behind the scanned images, so to speak. That sounds crazy, but the result is that the pages you look at are complete photographic reproductions, and yet the document is fully searchable!

To be honest, the OCR process is so time-consuming that I don’t enable it for books & magazines. But for invoices and loose sheets of paper, this is incredibly useful. I do not need to organize it – text search does it all!

I’ve cut up some 10 meters of books already, and turned them into PDFs. Yeah, it hurts a little at first, but hey.

For reading PDFs, I use the Mac’s built-in Preview, which is a lot better (and faster) than Adobe’s, eh… junk.

For locating documents, by file name or by content, there is Spotlight in the Mac, which also works with a server. This search technology is fast enough to instantly locate documents in many dozens of gigabytes of data. And since it’s available to all applications, there are some great front ends for it such as Yep, Leap, and Papers. I’ve been using DEVONthink Pro Office for all my docs and notes, because of its integration with the ScanSnap.

The above is all for the Mac, but there are probably similar offerings for Windows.

But the real revolution is much more recent…

There’s an “app” for the iPad, called GoodReader. This little bit of software lets me put over a thousand documents on the iPad and actually be able to find stuff, read stuff, and manage stuff. About 25 GB so far. Offline.

Which means I can now manage my entire collection as a folder on the server, add books, reorganize as needed, add tags and quickly access it from multiple Macs through Yep, as well as have the entire set on an iPad.

The Ultimate Bookshelf, no less, if you ask me. Alan Kay’s DynaBook has become an affordable reality.

To put it differently: food for thought – especially slow food for slow (off-line) thought, as far as I’m concerned!

The thing is, I love to get into new adventures, and I also really want to bring across the joy and excitement of it all. But what’s new for me may not make much sense to you, and what’s new for you may not be new for me.

There is a huge variety in what you, collectively, dear readers, may or may not already know and in what interests y’all. Even if we narrow the field down to “computing stuff tied to the physical world”, as this weblog does.

My approach has been to just throw everything together and write new posts in a fairly chaotic whatever-comes-to-mind-first order. Sometimes about raw electronics or micro-controllers, sometimes about hardware or software techniques, and often simply about what catches my interest and keeps me occupied. My plat du jour, so to speak.

There’s a problem with this, and it’s perhaps gradually getting worse: it may not help you with getting started. This daily weblog has an alphabetical and chronological index, listed at the bottom of each page, and updated from time to time – but that’s a bit like trying to learn how to swim by jumping in at the deep end, isn’t it?

A few days ago, my daughter asked me about how to learn programming. I was shocked – because I don’t know !!!

What I do know is that learning something as complex as programming really well takes years (my take on it is at least a decade, seriously!). Of course you don’t have to learn everything in depth and become a pro at it all. More often than not, we just want to make a nice sandwich, not become a master chef or start a new career.

Malcolm Gladwell has written several times about the “10,000 hours rule”, which says that to get really well at something you have to throw at least 10,000 hours at it. Learning, struggling, wrestling, pondering, agonizing, and… enjoying your progress. For at least 10,000 hours, i.e. 10 years of 4-hours-a-day – being obsessed helps!

Wanna learn something really well? My advice: start today. And prepare yourself for a fascinating marathon.

The trick IMO, is to define success in smaller steps than you might normally do. Got a blinking LED? Celebrate!

Here’s the secret: there’s an incredible (yet vastly under-appreciated) advantage of open source hardware and software. That advantage is that every hurdle can be overcome. You’re not fighting a closed system, nor a puzzle which only others can solve. You’re fighting the challenge of figuring it all out. With nothing but hardware and software which can be 100% inspected and documentation which can be found. When stuck, you can have access to people who know more about it and are often willing to help you along to solve your specific puzzle.

Let me rub it in: there are no show-stoppers in this game. The worst that can happen is that you run into real-world limitations of either atoms or bits or time, but there’s an immense body of knowledge out there. Get ready for this, because here’s a fact for you: if it can be done, then you can do it. And if it can’t you can find out why. This is technology – it works on logic and insight, all the way down.

But there are two constraints: 1) it takes time and effort, and 2) nobody is perfect.

What this means is that sometimes it will take more time and effort to get to the bottom of a problem and solve it. And we all make mistakes, cut corners, run out of steam, or grow impatient at times. Part of the game.

I’m no different. I didn’t get to figure out things better than others. I stumble and fight as much as anyone, of course. But I do spend time and try to push through – especially when I get frustrated. Because I know there’s an answer to it. Always – though sometimes unexpected or unsatisfying (“it couldn’t possibly work, because …”).

Back to the real issue: how to get started with all this stuff.

Ok, to stay close to home let’s assume you want to learn more about “computing stuff tied to the physical world”. If you’re starting from scratch (which is a relative concept), my suggestion would be to look for example projects which interest you, and start off by trying to repeat the same project. Find a web site or a book describing a project which fascinates you, and … spend time with it, just reading. If it sounds too daunting to reproduce, then it probably is – in that case, look for a simpler project to get your feet wet cq. cut your teeth in. You’ll get a much bigger boost from succeeding with a simpler project at first, and then tackling the bigger one.

I used to have lots of practical experience in electronics, from years of fiddling around with it as a teenager. Yet here’s the project I picked as first one to get back into this game: a trivial electronics kit. It was a no-brainer in terms of complexity, and there was virtually no risk that I’d fail at assembling it. Sure enough, it worked. And guess what: this little project got me excited enough again to … write over 900 weblog posts, and spend the last few years fiddling with today’s hardware.

The reason it seems to work for me, is what Steve Jobs once described as: The journey is the reward. So true.

If you can set your goals and expectations such that you get a really nice mix of learning experiences (i.e. struggles ending in new insight) and successes, then you’re in for a wonderful journey. It’ll last a lifetime, if you want it to.

I will try to help where I can, because that’s one of my central goals with this weblog, but I’m not going to turn this site into a handholding step-by-step and just-follow-me kind of place. Because the second goal of this weblog is to encourage creative work. Which is what you get to once you get past some initial hurdles, and are (at least partly) on your way to becoming a 10,000 hour master of some topic aligned with your own interests.

The “steepness” of this weblog is not there to frustrate, of course – it’s unavoidable, IMO. And I encourage you to bite the bullet with each bump you run into. It’s part of the game to be able to find your way in, and when you do you will have gained the experience that everything in this field can be explored, learned, and reasoned about.

I’m not handing out pre-packaged fish, I’m trying to show you the fun that comes from fishing!

Having said that, I do have a request for y’all, dear readers: if you’ve wrestled your way through some of these weblog posts, and came out wishing that something very specifc had been presented differently, or summarized, or linked to, then please do let me know (in the comments or by email). Most people who struggle and come out on top quickly move on to the next challenge, happy they now understand something better than before. But you can do your fellow future readers and strugglers a huge favor by explaining what the difficulty was. It’s often as simple as “if you only had mentioned at the start that …” and things can sometimes becomes so much clearer. I’m at the writing end of this weblog, see, and I never know where the confusion or lack of detail sets in. Please help me learn – about you, about how to reduce unnecessary steepness, and about all my mistakes, of course.

Anyway. Onwards with the adventures!

To the right – not visible here – is the main electronics corner, which will be shown in tomorrow’s weblog post because of another little project I’ve been working on. Let me explain the various bits ‘n bobs you see here:

It might seems odd, but this is all there is to the JeeLabs, ahem, “empire”.

The Vancouver view always brings back lots of good memories from a year-long stay there, a couple of years ago. An amazing place, in terms of cultural diversity and with its breathtaking nature wherever you go.

I also wanted to show you this to illustrate how little is needed to sustain a small shop. It wouldn’t be sufficient if you’re chasing riches and fame, but if all you want is to have fun and keep going, then hey, it’ll do fine.

JeeLabs would have been totally unthinkable on this scale two decades ago.

I’d like to go on a small excursion of what it’s all about, why it matters, and unpredictable stuff, such as the future.

This weblog started roughly three years ago. I love tinkering with technology, I love learning more about it, I love making new things (even if it’s only new for myself). Especially when it’s about mixing software, hardware, and mechanical stuff. I describe myself as an architect, a hacker, and a maker, and I’m proud of it. And I decided to write about it. One day I didn’t, the next day I did – it’s really that easy. You could start doing it too, any day.

A weblog is a publishing medium. Push. From me to you – whoever you are and wherever you are. As long as I enjoy writing it, and as long as you enjoy reading it, we both win.

One crucial aspect of this process is that we need to share the same interests. If I tried to write about culture, nature, politics, or music, chances are that we’d no longer be in sync (and I might have very little interesting to report!). We all differ, we all embody our own unique mix of interests, opinions, and experiences, and there’s no reason whatsoever to assume that a shared interest in technology means we share anything else. The great thing is: it doesn’t matter. We are linked by our humanity, and our diversity is our greatest asset. Vive la différence!

So how does this weblog thing work? Well, from what I’m writing about and have written in the past, you can tell where my passion lies. And you have the simple choice of reading and following the posts on this weblog – or not. From your comments and emails, I think I get an idea who (some of) you are. We’re in sync.

This process excites me. Because it transcends culture, age, background, and all those other aspects in which we differ (and don’t even know about each other). We can share our interests, learn from each other, exchange tips and ideas, and all it takes is an internet connection and the ability to read and write in English, even if that’s not everyone’s native language.

But weblogs publishing is an asymmetric process – there’s no real dialogue going on at all. I don’t really know who reads this. There might be thousands of readers coming back every day, or there might be just those who post comments – I wouldn’t know. I used to care about that, but I no longer do. I don’t collect stats and I don’t “track” visitors. It’s just another distraction and life’s too short. But more important to me, is motivation: my goal is not to have an “important” blog, a big readership, or lots of fans. Nor a big shop or many customers, for that matter. My goal is to have fun with technology, learn as much as I can, invent new stuff, and share to inspire others to do the same. It took me a long summer break to figure this out.

Of course I have my preferences, and of course there are areas where I know more and less about. The field is way too large to dive into every topic, let alone build up expertise in each – although I do consider myself reasonably open minded and knowledgeable about a decent range of technical domains. And those gaps? Well, that’s the challenge, of course: filling one little gap each day – day in, day out!

So what does this mean for the future?

I see no reason why any of this should stop. It’s proven to be sustainable for me, and there’s plenty of material to go into and talk about to last a lifetime. As you may have noticed, I’m moving away from a pure hardware focus in this weblog. The central theme will definitely remain “Physical Computing in and around the house”, but there’s more to it than the ATmega + RFM12B that form a JeeNode, and I’d like to explore a wider range of topics, including software and data processing, and probably also mechanical aspects (construction, CNC, 3DP, bots):

I do have a little request I’d like to make: whenever you read a post on this weblog and have a suggestion or insight which is relevant, please consider adding a comment. I tend to go with the flow (of ideas), and I tend to pick the easy low-hanging fruit first. Suggestions made in recent days on all this scary 220V power measurement stuff have helped me greatly to better understand what’s going on and to come up with more experiments to set up to try and figure it all out. I encourage you to point me in the right direction and to point out mistakes.

Who knows, it might lead to a post which is more useful to you. We’ll all benefit!

For the first half of the summer, I’ve learned to relax and not go online, even when at home. And for the second half, we’ve been going out, mostly short trips around the country – like a few days by train + bike in “Drenthe”:

And a quick trip to Paris:

Paris? Yes, that’s Paris. There’s a vineyard at the Montmartre, not far from the Sacré Coeur.

So is this:

Don’t believe me? Ok, here’s a more traditional image:

(all vacation pictures by Liesbeth, as usual)

Anyway, it’s good to be back. I’m looking forward to smell the solder fumes, burn my fingers, and see chips go up in smoke again – eh, something like that … ;)

Nifty stuff. Magic almost… if you take the water analogy, then it’s similar to pushing water up a mountain! Wikipedia has a schematic with the basic idea:

Think of the coil as a rubber band (I’ll use a gravitational force analogy here), then closing the switch is like stretching it from the current voltage to ground. Opening the switch is equivalent to letting it go again – causing the rubber band to contract, pulling the end back up and then exceding the original height (voltage) as it overshoots. The diode then sneakily gets hold of the rubber band at its highest point. The analogy works even better if you imagine a cup of water attached to the end. Well, you get the picture…

The trick is to repeat this over and over again, with a very efficient switch and a good rubber band, eh… I mean inductor. The way these boost regulators work, you’ll see that they constantly seek the proper voltage (feeding a storage pool at the end, in the form of a capacitor).

Enough talk. Let’s look at it with a scope:

What you’re seeing is not the output voltage, which is of course 3.3V, but the variation in output voltage, which is measured in millivolts. IOW, 45 times a second, the regulator is overshooting the desired output by about 20 mV, and then it falls back almost 20 mV under 3.3V, at which point the booster kicks in again.

Let’s load the circuit lightly with a 10 kΩ resistance, i.e. 330 µA current draw:

No fundamental change, but the horizontal axis is now greatly enlarged, because the discharge is more substantial, causing the boost frequency to go to 2.2 KHz.

With a 1 kΩ load, i.e. 3.3 mA current draw, you can see the boost working a bit harder to charge up, i.e. the slope towards ≈ 20 mV above 3.3V is more gradual:

Keep in mind that the difference is also due to yet more magnification on the horizontal time axis. The boost converter is cycling at 21.1 KHz now.

With a 330 Ω load, i.e. 10 mA current draw, the wavevorm starts getting a few high-frequency spikes:

The total regulation is still good, though, with about 25 mV peak-to-peak ripple.

Now let’s simulate what happens with the RFM12B transmitter on, using a 100 Ω load, i.e. 33 mA current:

Looks like the regulator needs more time to charge than to discharge, at this power level. Still the characteristic “hunting” towards the proper voltage level.

With a 68 Ω / 50 mA load, the regulator decides to use more force, losing a bit of its fine touch:

The scope’s frequency measurement was off here, it probably got confused by the high frequency components in the signal. Repetion rate appears to be ≈ 65 KHz. But now the total ripple has increased to about 70 mV.

That’s probably about as high as we’re going to need for a JeeNode with some low-power sensors attached. But hey, why stop here, right?

Here’s the output with a 47 Ω load, i.e. about 70 mA:

Whoa… that’s a ± 0.05 V swing, regulation is starting to suffer. I also just found out that the scope software has peak-to-peak measurement logic built in (and more). No need to estimate values from the divisions anymore.

Note that a 70 mA current at the end will translate to some 200 mA current draw on the battery – that’s the flip side of boost regulators: you only get higher voltage by drawing a hefty current from the input source as well.

Until this point, I used a standard 1.5V alkaline battery, but it’s not fresh and showing signs of exhaustion at these power levels (the output was a bit erratic).

To push even further, I switched to a fully charged Eneloop battery, which supplies 1.2 .. 1.3V and has a much lower internal resistance. This translates to being able to supply much larger currents (over 1 A) without the output voltage dropping too much. In this case, the change didn’t have much effect on the measurements, but I was worried that continued testing would soon deplete the alkaline battery and skew the results.

To put it all in perspective, here is the output with the same 47 Ω load, but showing actual DC voltage levels:

So you see, its still a fairly well regulated power supply at 70 mA, though not quite up to 3.3V, as it should be.

One last test, using a 33 Ω resistor, which at 3.3V means we’ll be pulling a serious 100 mA from this circuit:

Measuring these values with a multimeter gives me 3.16 V @ 89 mA, while the resitance reads as 32.7 Ω – there’s some inconsistency here, which might be caused by the high-frequency fluctations in the output, I’m not sure.

But all in all, the AA Power Board seems to be doing what it’s supposed to do, with sufficient oomph to drive the ATmega, the RFM12B in transmit mode, and a bit of extra circuitry. A bit jittery, but no sweat!

Update – With a 10 µF capacitor plus 10 kΩ load the limits don’t change much, just the discharge shape:

The same, at higher horizontal magnification:

Note that AC coupling distorts the vertical position, it’s still ± 18 mV ripple, even if the up peak appears higher.

The task ahead is to move on! This must not become a blog about my ability to function (or not) in the context of JeeLabs. I’ve been doing a lot of thinking, and talking to people around here.

There’s a pattern. It goes as follows: I start on a big new challenge. Push really hard, get totally in the flow, and get lots of things done. This can last for days, or in the case of JeeLabs: several years. Until, gradually, other mechanisms start taking over, governed by obligations and expectations, essentially.

The reason this has worked so well with JeeLabs, is that the weblog was simply a report of what was happening anyway. A diary. Easy to do, and useful for me as well, to go back and review what I did. The shop just gave it more direction: making stuff happen was already a given, so making stuff which others can use as well was really just “low hanging fruit”. Easy to include, and very helpful to stay focused.

I think that over these past two years, I’ve unconsciously moved deeper and deeper into this pipeline. From doing it all as challenge and exploration, came the desire to describe it all more and more on the weblog. And from there it all evolved into making sure an increasing portion of this would end up as products in the shop.

It’s not quite the Peter Principle, but in a way, I’ve gradually drifted away from what this was all about: exploration, learning, and yes, also sharing. That’s why I started JeeLabs, and that’s what I want to continue doing with JeeLabs as much as ever.

I came across some interesting articles these past few days. Seth Godin talks about business needing to be of the right size. In my case, that means: sustainable. No more. No less. I’m confident that I can figure this one out.

Paul Graham talks about Maker’s vs. Manager’s schedules. Real life has a way of interfering with makers. Tinkering requires concentration, for all but the most trivial and obvious projects. This would explain exactly what happened here – as I kept ahead of the curve with weblog posts and shop items, all was well. I was in the flow and tinkering all day in the fascinating and endless world of physical computing. The emphasis was on the right stuff, and the rest followed effortlessly. Really. The weblog was oodles of fun, even with a daily post, and so was the shop, which is filled with interesting and new experiences about the world of atoms, production, and fulfillment.

I don’t want to list the projects here which I have already started up or new ones I would love to go into. It’s all fun, except that even just thinking about listing them drives home the fact that they are all out of reach for me!

Got to track inventories, order stuff, find second sources, juggle the cash flow, get stuff assembled and tested, deal with back-orders and new orders, handle sales / tech support emails, and more. Welcome to doing business, eh?

I’ll share a secret with you: I liked so much doing the daily weblog when it went well, that I’ve been pondering for the last week about how to resume this weblog on a daily basis. Conclusion, alas: it can’t be done. I need to be on a maker’s schedule again, to use Paul Graham’s terms. And both the weblog and the shop make that impossible.

Something needs to change.

No more daily weblog. Maybe after the summer, if I can get ahead of the curve again. Instead, I’d like to do a couple of regular columns – such as the Easy Electrons series, which I really want to keep going. Maybe a second series, but no promises yet. And posts on an irregular basis, when there is something substantial to report. I’m not going to water down the posts and write about trivialities. Nor am I going to just report about what others do elsewhere. You’ve got the same access to internet as I do. The JeeLabs weblog will remain about original content. For noise and fluff, I’m sure you have plenty of choices elsewhere.

The webshop is currently not in optimal shape. Too many out-of stock cases popping up all the time. I’m solving this by scaling up. Getting components by the thousands where needed, and getting products assembled by the hundreds where possible. I’m also going to do something painful: raise prices. I’m serious about JeeLabs. It is going to stay, and it needs to be run in a serious, sustainable manner. I can pour in my time and energy. But the figures have to add up, in a way which matches the scale at which JeeLabs operates. There are some economies of scale, but obviously not in the way DigiKey or Apple can operate :)

The shortages won’t go away overnight. I ordered 500 relays in January. Expected a first batch end of that month, only to be told a week ago that it was “pushed back” to the end of April. I came across a second source, so hopefully mid March I can provide relays anyway. ATmega shortages are over. Same for several other important items. I’ve got outstanding orders and agreements for hundreds of units for just about all items. I understand the risks and I’m learning the ropes. I just need to get better at it so it won’t take so much of my time in the long run.

Because in the end, JeeLabs is all about exploring and inventing. And, once those are back in the picture, sharing.

Onwards!