With the Sony PRS-505 ebook reader hitting the market I instantly knew I need one. Now that I hold it in my hands, it’s love at first sight. I’d say with chewing on this nicety, my hunger for useful gadgets is cured for a while.

Apart from the sleek design, the most important things securing my choice were the courtesy of Sony to include an SD card slot, and the USB Mass Storage interface, as these two features ensured that the reader can be extended for less (not that the 200MB internal flash can’t hold enough books for many commutes), and will communicate seamlessly with a Linux PC.

This eInk display technology is a salvation for the eyes of many, including myself. An anti-glare, daylight readable, not background-lit, high contrast, 8 grey levels display makes my LCD-strained eyes very happy.

As I was planning to use this device to read not just books but also to keep reference manuals and tutorials at hand, I was curious about the ebook formats it supports. So the first thing I did was playing around with various document formats. The rest of this post is dedicated to this topic.

Text files are a developer’s friend. Fortunately, these are laid out quite fine by the reader. The TXT files appear in the booklist with name of the file as the book title, and the file creation date as the book author. The reader provides 3 zoom levels, with 30, 25, and 20 lines of text per page displayed in portrait mode, or 15 + 2, 12 + 2, and 10 + 1 overlapping lines per (half) page in landscape mode. The font used to render txt documents appears to be Bitstream’s Dutch 801 Roman BT. It seems ISO-8859-1 is assumed being the character encoding of text files.

When an ebook gets opened the first time, the reader works for a couple of seconds to paginate the contents, however, the results get cached, so this only slows things down once per ebook (per zoom level used).

RTF documents add the features of multiple font faces and font decoration to be used. Also, it is the document title and author that gets displayed in the booklist, so these need to be set up properly for easier lookup.

The next widespread format supported is PDF, though it has some issues. The reader’s screen size is too small to display an A4 or a Letter size PDF in a readable way. You may use the landscape function, which shows the top or the bottom half of the page. This, in together with the zoom function results in a readable half-page (without the margins), but the zoom level resets to default when turning page. Furthermore, special fonts/charsets don’t always render properly, and password protected PDFs don’t even show up in the booklist.

On the positive side, internal links in PDFs can be used to navigate within the document. Ah, and I’ve found quite a few reader-optimized ebook titles in PDF format at Feedbooks.com.

Documents in Sony’s proprietary ebook format, BBeB, obviously work the most seamless, providing three zoom levels, where the number of lines displayed depends on the font size settings of the ebook too. However, it’s hard to find anything useful in this format outside the CONNECT eBooks universe. I’m planning to write about tools for creating BBeB documents in a later post.

Concerning pictures (jpeg, png and gif formats), the PRS-505 is littlesomewhat slow on rendering, and with the very limited colorspace of 8 gray levels, the PRS505 is not likely to be used as my primary electronic photo album. However, it is good enough to enjoy my favorite comics, what more, probably an ideal device to share the greatest cartoons of savage chickens with my friends in the offline universe.

Finally, regarding the MP3 playing capabilities, while it is certainly a gimme feature to allow listening and reading at the same time, I don’t yet consider it a big thing, but time will tell whether I’ll use this ebook as a walkman too. For now, I haven’t even tried this feature.All in all, it is a charm to hold and read on. It is definitely worth all the 300 bucks of its introductory price tag.

I have spent countless hours eager to put together something useful, or just deciphering or dissecting games for a better understanding of how they work. Then, when I started drawing Mandelbrot sets, I realized the limitations of the 1MHz CPU, and moved on to a PC.

Even after these machines have finally been replaced by PCs, they lived on in form of emulators, such as the excellent free softwares VICE and Frodo to name a few. Emulators have appeared on many platforms ranging from DOS to UNIX to Java to Dreamcast and a whole lot more. Frodo was even ported to EPOC OS, thus runs on Psion Handhelds, and even on some Symbian Smartphones. I too have started implementing an emulator, and got as far as a emulating the 6510 CPU before abandoning the project to do something more useful instead.

Of course, data needed to be transferred to this new, virtual world, for which purpose, different tools have emerged. I myself used the X1541 cable and the wav to prg converter. A couple of different file formats have also emerged to store C64 tape and disk images.

In the meantime, a single chip version of the C64 has been designed. It is packaged within a joystick, comes preloaded with some 30 classic games, and only needs 4 AA batteries and a TV to connect to. The C64 Direct-To-TV and its second generation successor, the C64D2TV are so cheap many C64 owners bought it just for fun, and of course, started taking them apart, and with a little hacking, made them a fully functional C64, some even made them appear as one.

With hardware extensions still being developed to this platform, one can use an SD card as a modern replacement of the floppy disk with the 1541/III project, or even connect to ethernet networks with a LAN card, to name a few. With my limited skills in wiring/soldering, I’ve only built an RS232 signal level converter only to give a second purpose to my C64 as a text terminal to my PC.

On the software side, development hasn’t stopped either. New operating systems have been created to the C64, such as LUNIX and Contiki that added TCP/IP support, and even let you reuse your C64 as a web server (ok, not a high-performance one, lol), what more, some sick software lets you browse the web from a C64.

One may say there’s not much point in developing on such an old, limited platform, but think of it: those who master programming such a limited device, will for sure excel in programming embedded systems too, where there are similare restrictions even today.

All in all, C64 was not only successful because of its “advanced” features in its time, but is also successful due to the simple, understandable, yet extensible hardware design, that lets hobbyists create interfaces that keep the connectivity of the core up-to-date, which ultimately ensures many years still to come for the C64.

An accelerometer is capable of measuring vibration, motion, acceleration, and gravity, to name a few appliances. Assuming the sensor is fixed to an object, the readouts can be interpreted in many ways. It may detect the motion of a building, the tilt of a camera, the acceleration of a car, and so on.

Accelerometers are calibrated to read zero when forces cancel out each other, that is free fall, for example. When an accelerometer stands still on some surface on Earth, it reads 1G as the vectorial sum of the readings on its three orthogonal axes. The two basic parameters of such sensors are the number of axes (1 to 3) and measurement range. The range of the sensor determines its potential uses, with simpler implementations only able to determine a rough tilt, to high-precision ones capable of measuring heavy vibration.

But how does it work, one may ask. Well, the most widespread accelerometer implementation is MEMS (that is a Micro-Electro-Mechanical-System), basically a piece of hanging microscopic weight that changes its electrical parameters when a force bends it, and an auxiliary circuit measures and quantifies this alteration, all on the same wafer of silicone packaged into a single chip.

Let’s take a look at what ways can it be used. The classical, industrial usage of accelerometers include building-control systems (sensing motion and vibration), airplane navigation systems (that only rely on inertial changes to tell where the airplane is), car-safety systems (to determine when an airbag need to be blown). Accelerometers have also been used for mapping land features otherwise hard to measure due to the lack of reference points (e.g. tunnels and caves).

New appliances have emerged since, with airbags became more and more widespread, and the price of accelerometres have fallen while the size of the sensor was shrinking. Then, all of a sudden, embedding them into notebooks and hand-held devices became feasible, opening up innovative ways of extending the computers’ awareness of the surrounding physical world.

An embedded sensor’s readings may save your data by issuing emergency-shutdown for the HDD when gravity tilt suddenly disappears, which means the notebook is free-falling, and is about to crash-land on hard surface. This feature appeared in MacBooks just a few years ago, using an accelerometer often referred as sudden motion sensor. By providing access to the sensory readings, however, Apple has opened up a way for a new breed of fun applications, utilities and games, including MacSaber, my personal favourite. In recent news, iPhone’s tilt sensor has just been put into action.

An accelerometer in a hand-held device, such as a phone has even more potential, as these gadgets are moving basically all day. Recognising gestures could simplify the interaction, for example answering a call could be as easy as raising the phone to our ears, while a simple shake would reject the same call. An accelerometer provides enough info to use as a secure-guard: the walking-pattern is different for every individual, so the phone can literally sense, and therefore act, when it has taken away from its owner. Check this link for some other ideas.

So why not use them in input devices? Taking a look at Gyration’s air-mouse or Nintendo’s WiiMote clearly shows the advantages of accelerometer-equipped input devices, which bring more spatial freedom into the interaction, so much you can even crash your TV screen with. Industrial grade data gloves can capture the fine motion of the human hand with accelerometers. One may say these tools are very expensive, but check out the accelerometer mouse project from students of the Cornell University, who created a mouse glove from a mere 13 dollars.

This latter project inspired me too, so I grabbed a USB 3-axis accelerometer from phidgets.com to experiment with. Probably not the cheapest solution, but it worked right away as I plugged it into the USB port. Not that I’m anything closer to my goals with that easeness.

All in all, starting in the heavy-weight industry, and gradually shrinking into mobile appliances, accelerometers have become part of our everydays, and hold a huge potential for improving Human-Computer Interaction.

Phidgets are a painless way to extend a USB-equipped computer’s interactions with the physical world, providing a wide range of sensors, displays, and controllers as simple as plugging them in. With an acceptable pricetag, phidgets open up a world of new possibilities for software developers with only limited skills in electronics, ultimately resulting in some fun projects.

Phidgets Inc. provides software drivers and libraries for Windows, Windows CE, Mac OSX, and Linux, including driver source code (with a restrictive license, though). There are APIs for COM, Java, .Net, C, ActionScript, and bindings to a variety of languages to speed up development. Browsing the web and the forum for python support I’ve also came across the python-phidgets and the phydget projects that provide python bindings.

I decided to give phidgets a try, so I’ve purchased a 3-axis phidget accelerometer, a phidget interface kit with text-LCD, and a few analog sensors to measure temperature, magnetic fields, and light, and also a touch sensor. The sensors are going to be used in a home-automation project, while the accelerometer will somehow become an input device (thinking of something like the accelerometer mouse).

With the limited time I have spent with my phidgets so far, I’ve added accelerometer support to phydget (should you be interested, here’s the source code for my accelerometer-enabled version), and created a minimalistic visualizer for the accelerometer readings using the excellent vpython library. More to come as soon as I could make some progress in either of my planned phidgets projects…

Then I’ve found that the connectivity suite it comes with has linux support next to nil. No problem, you can’t have it all. And a simple search revealed two open source apps, plptools and psiconv, the former to communicate with the machine, the latter to convert file formats used by Epoc, the handhelds operating system created by Psion, to something less exotic.

At that time, psiconv had limited support for Psion documents. Being curious by nature, I wanted to know what’s buried behind those nice icons. I’ve spent countless hours deciphering the Sheet file format, armed only with a hexdump app, an ever evolving test parser, and lots of patience. All this turned out to be fruitful, as my findings became incorporated into both the documentation and the implementation of psiconv, which then was even used as an import plugin for gnumeric. I’m still wondering whether anyone has used it, though.

My affection was put to a long halt after my love of this machine broke with its screen cable. A design flaw all 5MX machines suffered is the wear-out of a small cable that connects their screen to the main board, which ages with every opening and closing of the machine. It usually lasts no longer than 2 years, mine wasn’t an exception either. I decided not to have it fixed for almost the price of a new PDA in 2001, and moved on to a different brand instead. Only later I realized how much I missed my old Psion. Fortunately, you can still get one for a very reasonable price on eBay. So I bought one again. And a Netbook, too. In fact, I’m writing this post on it. So now I’m happy again, even though I barely spend time using these machines, I wish I could.

Though these wonderful machines deserved a better fate, they are still thrive on the second hand market. As small as the population of Psion users who are also using linux was, psiconv never really gained too much attention, and only a handful of contributors cared to enhance it. Psion discontinued these wonderful machines, and the author of psiconv shows no interest in further development either. I guess, slowly I will acknowledge that time has passed over Psion PDAs, and put them on the shelf, next to my first beloved computer, the Commodore 64.