Fighting with computers

Computers are not always friendly.

Saturday, March 29, 2008

Reviving an old laptop


Not sure what is the proper adjective for a three year old laptop. But apart from the language issue the thing is that I was asked to give a clean start to an HP nc6000 laptop. It seemed a no-brainer to install Windows XP SP2 or so I thought.

While the install worked as expected, there were bad news afterwards: The system booted but nothing worked as expected: Graphics card,Ethernet, SD memory slot, Cardbus slots and Wifi adapter did not work at all.

I am not sure whether the laptop was shipped with a driver's CD-ROM or not. The owner told me he had nothing like that.

A few Google searches later I've discovered several drivers websites trying to make a buck out of the poor souls that could not find the drivers CDs. Some users also complained about HP not making the drivers available and, of course, standard drivers on SP2 not working with HP hardware.

Later on I did find an entry on an HP website that contained the drivers. The problem is that it actually contained too many drivers. It seems that under the same name the manufacturer has been using different peripherals. So I had to choose between an Intel or an ATI VGA adapter and among different Wifi cards. Eventually, after trial and error, I could get the system back to life with everything working. It took a while though.

I guess the moral is that you better keep your driver's CD at hand, just in case.

Oops, I swear the driver page I provide worked for me, but when I've checked the link it is no longer working ...  (?)

Sunday, March 16, 2008

Buying Arduinos in Spain

Unfortunately, my mood light project destroyed the microcontroller when I plugged in the protoboard shield with the RGB led while the power was on.

A few days ago I've ordered another arduino board that I would use as the controller for the mood light. I was looking for a cheaper alternative so I've found a good deal on eBay from NKC Electronics, a company in Florida that sells different kits. I bought from them a serial arduino (or Freeduino as they call it) in kit form.

While I am aware of two different companies in Spain selling arduino boards (but not kits), they have a shipping cost which is almost double than many USA-based companies. The fact that the Euro is now stronger than the dollar makes the shipping cost even cheaper now.

It is beyond my knowledge how come shipping cost from Florida to Valencia can be cheaper than from another city in Spain. But this seems to be the case. Of course a local supplier may be preferred if you are in a hurry.

Now that my only arduino at home is broken I am not able to test the motor shield I recently bought from Adafruit Industries. And I am not sure whether only the processor is dead or maybe something else. So I went back to eBay to look for an extra ATMEGA168 processor and an additional Diecimila board. However, I ended up buying them from NKC Electronics at their Yahoo shop, as they have the same price in there than on eBay.

It also occurred to me that a cheaper alternative may be the one offered by Modern Device Company and their Bare Bones Board. The idea is that all the serial communication is taking away from the arduino board. Instead a cable that contains the FTDI USB to serial is used. I've ordered one of these to give it a try.

Now I am waiting for three different new arduino boards to arrive!

Update: Not sure if Paul Badger (from Modern Device) read my above comments, but I've got a message from him today asking me to pay a few more dollars for the shipping. So that makes his offer not so appealing for Spanish buyers. I decided to keep my order and I paid up the extra cost.

Sunday, March 09, 2008

Arduino mood light

I recently saw the cool mood lamp by Philips and I liked it. What I did not like was the price. I set myself to discover what the industry has to offer in terms of high-power LEDs. It turns out that since the old 20mA red LEDs the market has evolved in such a way that it seems the light appliances of the future might be completely LED-powered.

Now there are 3W and 10W LEDs available. Either monochrome or RGB. I like LEDs as they last forever (I've never seen a LED that stopped working unless it was due to a current overload).

High power LEDs are not cheap but they are very easy to control from a micro-controller using PWM (Pulse Width Modulation). They need DC low voltage power sources.

I did a test with an Arduino board and a protoboard with a ULN2003 that I've used to control a 3W RGB LED.



I programmed a never ending random sequence and this is the source code. Just connect each led (R,G,B) to the outputs 9,10 and 11 of the Arduino. If you need more current then use a Darlington driver.

Let's see the schematic:

R=22 OHM/3W (for 3W RGB LEDs)


Update: I've added a new "candle" effect playing with random changes on color and intensity.



Update2: Several of you asked me for the candle effect code. I'm posting the whole source file that includes other effects too plus a couple of analog inputs that select the effect and the brightness.

Not impressed with Apple service


As I mentioned on my previous post, my iMac needs a new RAM. I called the shop to be sure they have a technician on the shop and I was told they had one from Monday to Friday. As it was Friday afternoon I thought that if I was lucky they could double check Apple's diagnostic software diagnose: Faulty RAM. This way I could be back home with the iMac in the same trip.

I brought the iMac to the Apple shop I've bought it from, but I was told I had to leave it there (why am I not surprised?) and luckily they will call me next Wednesday. In hindsight I realized they should have stressed the "luckily" part.

Next Monday I've got a call from the "technician". The conversation goes more or less like this: Hi Sir, this is from the Apple shop. I'm trying to have a look at your computer but it is password protected so I cannot log in. I mentioned him that all that I did was to run Apple Diagnostic software and I've got a RAM error right away. Using the system, however, was sometimes successful for some minutes, hours or days till it started to fail. Yes sir, but I need the password so I can log in. I still do not see the need nor the convenience of giving a complete stranger the password but given the way the guy insist I decide to give in and gave him the password.

As some other passwords of services I use are in the Safari cache I did changed my Gmail account password just in case. I am not comfortable with other people messing in my system that contains family photos and other stuff. (I did a full back-up copy in case you are wondering).

As I have not complained about any harddisk problem and as the Apple Diagnostic software is started from a DVD and not from my system HD I cannot understand why they are doing this but let's assume they will fix my issue.

On Thursdaythey have not yet called me so I called them. It was determined my RAM needed to be replaced, both banks. I told them I only had 1GB on a single DIMM, that was the default configuration when I bought the system. I was told that they were waiting for new RAM and they don't expect it to have it available till next week.

I'm glad I have not hard deadlines on the horizon as a simple RAM replacement is going to take them around 10 days (if I'm lucky). Maybe the local hardware shop is spoiling me but they use to have stock of popular RAM formats.

I'll keep my fingers crossed.