Fighting with computers

Just after installing a software update that required a restart (I guess a kernel or firmware upgrade) our iMac did it again: After the initial chime, it started beeping and it refused to boot up. In a previous post I mentioned that as three beeps means a RAM memory problem it may well be caused by a non properly seated memory module. So this time I remove the power cable and I opened the memory hood on the bottom of the case. It looked ok but, just in case, I took the memory out and I plugged it in again. It looked to fit well (before and after). Unfortunately this procedure caused no change on system behavior: After the initial chime the system will beep twice and then it will continue making three beeps until you power it off. Knocking the unit did not help either. It's time to consider the choice of sending the unit back to Apple. But as I could not do this on a Sunday afternoon I decided to try to learn more about the issue. Googling lead me to some awful stories. I guess I...

The March issue of Circuit Cellar Inc magazine is out and it features an article I've authored about the canvas painting machine I built a while ago. A video of it was also included here . It all started when I learned about another project on the net. However, though I have tried to contact the authors they've never answered any of my emails.

Just when the anger from a previous rip-off on eBay fades away, I'm watching myself doing it again: I was bidding on an item that had only 30 minutes left. I went to do other things and when I was back I tried to see what had happened. However, what I've obtained was the warning shown here. Apparently the auction had been canceled. After checking my emails I realized that I had been outbid by another bidder who actually won the bid. Nothing surprising here, but a few minutes later another email informed me that the auction can been canceled "Cancelled - Results Null and Void" was the subject. However not much useful information was provided, or so I thought We're writing to let you know that eBay has ended the following item you were bidding on due to factors beyond the seller's control: Item Number - 200201885499 Item Title - BRAND NEW *iPod touch* 16GB 16 GB WIFI,TOUCH WIDESCREEN As eBay removed the item, you are no longer obliged to send p...

I know it is not new, but I've been surprised when my younger kid told me he was selling several of his accounts of certain on-line games for some money to his classmates. I just hope he'll stay out of trouble, but I'm surprised of his entrepreneurship character.

In my recent trip to northern Finland I had the opportunity to use a cool network service in the Oulu area: panOULU is an open wifi network you can freely. Freely meaning several things: not only that you do not have to pay but also that you do not need any type of user ID, which is great if you happen to just be visiting the area for a few days. Just opening your laptop and being able to use the network with the peace of mind it is not going to cost you an arm and a leg it's just great. I was able to upload the photos to my Picasa account so my family and friends could be updated. This same action would had been outrageously expensive should I were using the GPRS or 3G connection (getting the photos printed and sending them by a courier service is actually cheaper than your cellphone data service). This week I've read that European regulators are asking the mobile operators to reduce users costs when using their mobile data services abroad. The point is that as far as the EC ...

Not much could I anticipate this morning when I woke up at 4:00am to be, as advised, two hours in advance the boarding time of my international flight to Paris. It was actually the first round of a tiresome trip to northern Finland. My final destination was Raahe but I was flying from Valencia to Oulu. And to do this it seems one possible choice was to go through Paris and Helsinki. I bought my ticket online, with the freedom that gives no having any miles program, to the cheapest seller (not sure it is the safest choice now, but read on). I usually try to avoid Madrid airport, but I recently read on a BBC News article that Paris – Charles De Gaulle – was one of the worst airports in Europe. The only problem I've got there in the past was that they tend to add letters to the gate numers, so you may have, for example, several 53 gates. Of course the tickets do not reflect this “feature”. I'm writing this on my laptop while sitted on a very comfortable chairs next to gate ...

For those of you using Windows you wonder who might need another tool than the free (and great) software to manage your photo collection and to upload selected ones to your Picasa on-line photo sharing web application. Mac users have been wondering for a while if there was a better way to get photos from iPhoto to Picasa Albums. I discovered this morning that there is a new upload software for Macs that integrates nicely with iPhoto (I'm not checking very often so this feature may be available for download for a long time, I just do not know). Things for Linux looked really bright when I saw a post claiming that you can install a similar software to the one you use in Windows for Linux. Actually it was too good to be true because what they have done is to package a Windows binary with WINE. Unfortunately this binary lacks the upload feature. So if you want to upload many files at a time it is better to copy on a pen drive and then use a Windows or Apple computer to upload the bat...

| View | Upload your own I'm visiting a school in northern Finland next week. This is the presentation I'm giving. It's intended for first year students so you'll find it very basic, and you'll miss the fun of some demos. By putting it here I have a backup plan if I lose my pendrive :-)

I'm still dealing with a non-responsive eBay seller after I've got burned by a non-working 8GB compact flash. I've seen that many people do not like to talk about this type of failures that happen on eBay from time to time. I'm still trying to get my money back from PayPal so maybe not everything is lost. But now I wanted to buy some cheap control chips for bipolar stepper motors. Nothing fancy with micro stepping or digital current control, just a simple chip that can also be used for other purposes too. I saw this video and I learned about the L293. It is an old chip that several manufacturers mark as deprecated. Instead of going to a local shop I went online to eBay and I saw several sellers have it available. I tend to favor European sellers if the price is right as I do not particularly enjoy periods longer than two months for delivery (something I've experienced first hand from Hong Kong lately). One of the sellers had a price that seemed ok, but they also di...

I know several nice Math software packages, mostly for Windows (Derive, Mathematica, MathCAD, Matlab ...). My university has licenses for some of them but I am not always on campus, using Windows, when I need some help. There are some free math programs too (Scilab, Octave, Maxima, Axiom ...). What it is not always known is that there is an interesting set of on-line calculators and solvers that sometimes can help you get the job done without installing anything. Quite interesting when you are not even using your own computer. For easy calculations and units conversion Google calculator is a neat tool. How do you use it? Just type your calculation on Google search box (i.e. " 5/sin(32) " or " 25 celsius in farenheit " ). Really worthwhile to convert between American and European fuel economy units! But maybe you already have a calculator so this Google feature while nice does more or less the same. You may need to do something more advanced like online matrix calcul...

A few months ago I bought a shiny 20" iMac. While the initial impression was good, I was not happy after the trouble I had installing Leopard and certain incompatibilities it brought. Just when it seemed things were settling down I've got the system just dying on me after opening a large (120MB) PDF file. The screen turned black and then the system rebooted spontaneously. Another computer was on at the same time and it did not experience any problem, so I do not think that was because of a power spike. Today, when I started the system there was a multilingual message in a centered dark square telling me to press the power button for several seconds to shutdown the system (neither the keyboard or the mouse worked). I have never seen that image before (but I failed to take a photo), it contained the message in Japanse too. It happens to be an OS X kernel panic . When I powered on the system again I heard the welcome sound and next two beeps and then three beeps that repeated ov...

While searching the net for possible uses of old hard drive voice coil actuators I've came across this video. A video is worth even more than a thousand words so I'll let it talk.

Many times the answer is on the 'net, so when I wondered if my dead iPod could be fixed I started Googling. This post is one of the answers I have found. To make a long story short: iPods do not like to fall on the floor, they use to stop working as a revenge on the careless user. iPod mini has an Hitachi microdrive (same size as a Compact Flash memory but thicker) inside. You may wonder, as I did, if you can substitute the damaged microdrive with a solid state flash memory. The answer is yes. Have a look. And yes, you can replace the 4GB microdrive with a 8, 16 or even 32GB Compact Flash card to boost your iPod capacity. You can also replace the battery if it is not holding a charge too. Just be aware that not all the CF cards work.

When my son asked for a new MP3 with video player to replace his ancient Creative Zen micro I thought a new 8GB Creative ZEN will be a nice replacement. However the Zen micro units and the Zen V Plus have not been very reliable (at least not mine). It seems the obvious choice would be to go iPod nano . An option I would agree with but because my iPod decided not to allow writing new songs anymore a few weeks ago. Several things seemed to favor the 8GB Creative ZEN: screen size almost double that of Ipod, a built-in radio and a built-in microphone enabling the use of the unit as a voice recorder. On the cons it was the size and thickness factors that played against Creative's. Unfortunately, the 8GB unit was not easy to find, but somehow Santa managed to get one just in time. It was a disappointment to discover the unit display did not to work just after opening the box. However, just to follow the instructions we fully charged the unit and transfered a whole bunch of songs (data t...

While I have to admit I am quite happy with the last Ubuntu version I have to mention several bumps I ran into: To my surprise, the usual way of installing ssh server did not work as expected. After doing sudo apt-get install ssh I've got installed and running the ssh daemon, but no connection was possible. Well, not sure what happened, but now it works ... I cannot trace what exactly the problem was though it seems two daemon processes were launched by error. Realplayer is another problematic application that use to work in previous versions but now it creates trouble . The adobe Flash player is (almost a requirement if you want YouTube videos to play) another tool creating trouble at the moment. The install will fail but some magic can be done to get it working too. VMware's vmplayer is another example of this apparent regression of tools. It was working before but stopped working not. Fortunately help was on its way and it can be fixed too. None of these problems has been...

The second system I installed Gutsy was probably angry with me. Or maybe I was just downplaying Murphy's laws. It was an old Asus Pundit-R computer and it was a mess. The initial install went ok as I kept my /home partition untouched not to loose any data. However since the first moment the screen colors looked awfully washed out. Of course this same computer was just happy with almost any previous version of several flavors of GNU/Linux, so it had to be something new. While Google comes in handy most of the time, the problem is to choose the right keywords. It took me a while (more than I am willing to admit) to find this bug report and the solution . And while doing the silly thing with the Ubuntu logo above, I discovered the GIMP version that comes with Gutsy fails to open a URL. A feature that has been working for ages. ( Fix: sudo apt-get install gimp-libcurl ). In the process of fixing the graphics driver problem something happened to compiz that now prevents me to use any ...

After some weeks waiting to allow the news to settle, I've decided to install the new release of Ubuntu known as Gutsy Gibbon. I have started with my laptop that was most needed of an upgrade as it was still running the same version I installed 18 months ago. At the time, Ubuntu required me to tweak several things to get the laptop running fine and still the memory card reader was a no go. This time installation was faster and everything worked first time (all but the WLAN led, while WLAN worked ok the led showing it was on didn't). No need to fight with any xorg config file to get the right screen resolution. Suspension worked nicely too (but I needed to go to the preferences menu to select the power save operations I wished: closing the lid will suspend the system). For the first time Firefox prompt a Java runtime install that worked ok, giving you the choice of what virtual machine you wanted, too. I've read some claims that battery consumption might be higher on this n...

Given the number of downloads, and the fact I wanted to use the red pen myself, I patched my previous converter code to include that. As before, the perl source code is available for download. The program will convert a g-note proprietary file format into an SVG file that at least Inkscape software (the one I use) is happy with. Luckyly one reader provided this link with the file format specs. Just type dnt2svg.pl your_dnote_file > converted.svg Windows users need to know they can get a free perl interpreter from ActiveState. Those with Apple OS X already have it in place (but you still need to know of to use a terminal).

New rules in France have been set up to punish on-line exchange of files. The new deal between the French administration, the recording industries and the Internet service providers is supposed to protect the artists' revenue. The deal is supposed to be against on-line movie and music exchange but I am not sure how easy may be to detect that a given user is downloading a song whose rights belong to a French corporation or artist. So it may well be easier to rule out any file exchange, just in case. We will see... Not everybody agrees on the idea that preventing music or video sharing over the Internet is going to improve sales figures, though. If the system they are putting in place in France does work, it may well be a market to watch carefully. I won't be surprised if, instead of the expected results (higher revenue for artists), a significant decrease on Internet users happens. Because of this, I think this is a social experiment we need to pay close attention to. Do not fo...

Many vector drawing programs do include a vectorisation tool so a vector representation of a bitmap can be obtained. I have used many times the one that comes with Inkscape program. However, I've just learned of another tool you can use. The fact the tool comes from Stanford makes you hope for very good or superb results. The picture on the left is a bitmap of a vectorised bitmap. The usefulness of that is just as a sample (but, of course, you do not want to get a bitmap of your vectorised output). The picture was taken from a recent Google Talk at our university. What makes this new tool unique is the fact it is an online service. You upload the bitmap from your web browser and after a few selections you download the result in either EPS, SVG or PNG format (the latter is a bitmap format though). The comparison you can find on the tool site shows an impressive performance compared to other vectorisation tools on commercial software (from Adobe and Corel). Update: Since this entry...