September 11th, 2004

flex brain!

Minicomputer, day 9: Airflow engineering

After a long hiatus, it was once again time to get cracking on the minicomputer. Recall that, in a previous post on the subject, I had mentioned I was concerned about the high temperatures within the case. With no airflow in the case, there was little the CPU cooler could do but recycle the air inside the case, that had already been warmed up by the northbridge.
And so, I decided I should construct something to replicate the airflow generated by the original PSU -- but of course, with a less noisy fan. And with the little heat-production of the C3 CPU, I could get away with much less airflow too. I still had that northbridge cooler-fan, and so I set to work...
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So, you ask: what are the results? Actually, the results are quite good. When idle, the CPU is at a temperature of 32 degrees with a case temperature of 19 degrees. Harddisk runs at 31 degrees. Yes, it's cooler now than when I did the previous measurements -- if you estimate a drop of 10 degrees in temperature, the temps are pretty much the same as back then.
When playing a DVD, the CPU runs at 46 degrees with a case temp of 23 degrees, and the harddisk is stable at 32 degrees. And when stressed (playing DivX'es fullscreen), the CPU runs at 49 degrees, case at 25 degrees and harddisk at 32.

It's mostly the case temperatures that are much lower -- and a lower case-temperature (actually that means lower northbridge temperature) means that all components run cooler. At a minimal gain in noise (I had to close the windows to block out the sounds from outside to hear the machine), I'm pretty pleased. Also, the air that's expelled by the fan is rather warm -- another indication that the cooling issue is now much improved.
  • Current Mood
    accomplished accomplished
Readman

Finished book: Pattern Recognition

Today, I finished 'Pattern Recognition' by William Gibson. I'm a bit of a Gibson-fanboy: he is, after all, the man who opened up Cyberpunk as a genre for the mass market. I love cyberpunk, and thus any of Gibson's work warrants my attention.

Again, this book is very much Gibson: the speed of the prose is fast, very fast. With a few words, Gibson can evoke a certain feeling, or paint a certain picture. That's a rare talent, and he's very good at it. It works.
However, in the plot-department, this is also typically Gibson. On a macro level, it's very much like Neuromancer or Idoru -- though of course the details are very different. Lone individual with a special talent is hired by shadowy organisation to check out some phenomenon shrouded in secrecy and security, while s/he doesn't know what the real issues are, and who to trust. Especially the ending shares quite a few thematic similarities with Neuromancer.

I enjoyed the writing and the story. And I enjoyed it especially because the setting is the present time. It's much more accessible than, say, Virtual Light, or especially Neuromancer. This is cyberpunk your dad could enjoy -- and that's quite a feat.
If you haven't read anything by Gibson, this book might be a good start. If you like it, you can move on to Virtual Light, or, if you're feeling adventurous, to Neuromancer.
  • Current Mood
    impressed impressed
Readman

You knew this was going to happen...

1 -- Leave a comment, saying you want to be interviewed.
2 -- I will respond; I'll ask you five questions.
3 -- You'll update your journal with my five questions, and your five answers.
4 -- You'll include this explanation.
5 -- You'll ask other people five questions when they want to be interviewed.


These questions are from klik (in Dutch):
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  • Current Mood
    contemplative contemplative
flex brain!

Hail to the king, baby!

It seems my most inspired time is in the morning, just before waking up completely. I tend to think up solutions for the problems I am faced with -- at least in the realm of programming and electronics. I had noticed that pin A4 did react to my settings, but pins A0-A3 didn't. So, I thought: I have 8 pins in port B that I can use, why not connect the ninth lead to A4?
And so I did that -- to little avail.

Dissapointed, I googled for 'porta pwm 16f628', and I saw that people set something in the CMCON-register, to turn off analog comparators. Intrigued, I opened up the datasheet and googled some more. The solution was simple: set the 7th bit in CMCON to turn off the analog comparators, and the pins will react like normal, well-behaved digital pins.

And now, I have 3 RGB-LEDs changing color via PWM. I'll clean up my code later and post it -- right now it's off to the showers and to bed!
  • Current Mood
    accomplished accomplished