Category Archives: Technology

Posts that relate to technology. Reviews, HOWTO’s, problems & solutions.

Aiptek HyperPen T-6000U tablet with Ubuntu 9.04

Posted on by
Reply

Getting the Aiptek T-6000U tablet working with Ubuntu 9.04 was relatively easy, following the directions here.

Summary:
Install the xserver-xorg-input-aiptek package.
Add a file called 10-aiptek.fdi to the /etc/hal/fdi/policy directory containing:

<?xml version="1.0" encoding="UTF-8"?> 
<deviceinfo version="0.2">
  <device>
    <match key="info.product" contains="Aiptek">

      <merge key="input.x11_driver" type="string">aiptek</merge>
      <merge key="input.x11_options.SendCoreEvents" type="string">true </merge>
      <merge key="input.x11_options.USB" type="string">On</merge>
      <merge key="input.x11_options.Type" type="string">stylus</merge>

      <merge key="input.x11_options.Mode" type="string">absolute</merge>
    </match>
  </device>
</deviceinfo>

Ubuntu 8.04 SSH login slow

Posted on by
Reply

SSH Login to my Ubuntu 8.04 machine was slow. (It would delay about 5 seconds after I issued the ssh command for the remote machine to request a password.) I believe this is because the remote machine is on my home network, and I have set up it’s hostname using host entries instead of having a true DNS name.
I edited the /etc/init.d/sshd_config file and added the single line:
UseDNS no
which fixed this problem as soon as I restarted the SSH server, with
sudo /etc/init.d/ssh restart

Acer Aspire One D150 – Ubuntu 9.04 Jaunty Linux

Posted on by
3

Installing Ubuntu 9.04 (Jaunty) on an Acer Aspire One (Model D150) worked quite well. I had to use an external USB CD-Rom Drive as the Aspire One does not have a built in drive, but after enabling the “Press F12 to choose boot device” menu in the system BIOS I was able to boot off of the external USB CD-Rom drive.
Ubuntu worked well with all the major hardware (video, wifi,wired-ethernet, soundcard, and webcam) and the only hiccup was with the built in microphone, which did not work out of the box (the microphone jack would work, just not the built in microphone.)

To get the built in microphone working, I had to install the latest version of the ALSA driver following the instructions I found in post 28 on this thread, as copied below:

So I downloaded alsa-driver-1.0.20.tar.bz2 from

http://www.alsa-project.org/main/index.php/Main_Page

I unzipped the package, I entered into the main directory of the package and then I typed:

sudo apt-get install build-essential ncurses-dev
./configure –with-cards=hda-intel
make
sudo make install

Then I edited /etc/modprobe.d/alsa-base.conf and I added at the end of file the line:
options snd-hda-intel model=acer-aspire

After the reboot I adjusted the audio preferences in this way:

Device: HDA Intel (Alsa mixer)
Preferences: The first 3 items and last 2 items (Front Mic is disabled!!!)
Input Sources is set as default at Mic (not Front Mic!!!).

Finally check that System->Preferences->Sound->Sound Capture is set to “HDA Intel ALC272 Analog(ALSA)” not “ALSA”

Electric Bicycle power circuit

Posted on by
1

Bolting a DC motor to the front basket of a bike and running a chain to the front wheel takes care of the mechanical linkage needed to make an electric powered bicycle, but you also need to provide power to the motor, and control that power in some way.
Luckily, the same place that sold me the 250 watt motor also sold a 40 amp speed controler. (It cost $33, or more than any single other part of my e-bike project.)
40A motor controller

The speed controler is controlled by most standard e-bike throttles, such as this one from Currie Technologies. I also attached two 12v 5AH batteries in series to provide 24 volts. Because I calculated that my 250 watt motor running at 24 volts would draw approximately 10 amps, (250/24 = 10.4), I added a 15 amp fuse to the circuit. (The first 15A fuse was replaced by a second 15 amp fuse after it saved my speed controler from damage when I accidentally reversed the polarity on the power…)
Continue reading →

Setting Netflix / Silverlight bandwidth usage

Posted on by
5

The netflix watch on demand video player uses Microsoft Silverlight. Silverlight has an “adaptive playback” mode which attempts to choose one of multiple bandwidths for your video (and switch on the fly if your internet connection has more ore less bandwidth over time).

To see what it is currently using, press the Control, Alt, Shift and D keys all at the same time.
CTRL-SHIFT-ALT-D gives diagnostic information on-screen.

If you would like to force netflix to use a specific bandwidth (typical sizes are 500, 1000, and 1500 KBps, or 50, 100, 150 kilo-bytes a second), press the Alt, Control, Shift and S key at the same time.

CTRL-SHIFT-ALT-S allows you to manually force silverlight/netflix player to use a specific bandwidth for playback.

This can be useful if you want the absolute best quality (and are willing to pause the movie every so often to let it buffer), or if you are willing to use a lower quality than your full network connection supports so that some extra bandwidth is available for other users or applications.

NOTE: I was unable to get the key-combos above to work in full-screen mode. I had to have the netflix player in a browser window for them to work. In addition, sometimes I had to click within the siliverlight window (for example, by pressing the play/pause button) before the key combination would work.

US GSM Bands (T-Mobile, AT&T)

Posted on by
Reply

AT&T and T-Mobile are the two main providers (in the USA) who provide GSM service. Below are the main cellular bands they use.

AT&T:
GSM: 850 and 1900
3G: 850 and 1900

T-Mobile:
GSM 1900
3G: 1700 (AWS) and 2100MHz

GSM bands not supported in the USA, but active in other countries: 900 and 1800.

Internationally, you may need the 900 and 1800 bands, especially in Europe and Asia (many south American countries work on the 1900 GSM band). If you have a “quad-band” phone it will work everywhere.

Sometimes these bands are called by acronyms instead of frequencies:
UMTS: 2100
PCS: 1900
DCS: 1800
AWS: 1700 (or simply AWS)

The advanced wireless system is a new block of bandwidth that has been opened up for use in the USA. AWS Overlaps with UMTS and DCS (1700/1800 and 2100) The convention appears to be labeling AWS with the number 1700, because 1800 and 2100 are already used to indicate other things.

Different channels on different tuners (MythTV)

Posted on by
Reply

My SiliconDust HD HomeRun has a relatively good HD tuner, but it’s not quite as good as the built in tuner on my TV at picking up stations that are extremely strong and have multi-path reception problems. Although the signal My MythTV box reception of Fox TV would intermittently cut out as the SNR would drop too low to enable reception (even though, or, because the power level was pegged at 100%).

I purchased a Skywalker 16db attenuator, and it successfully lowered the signal strength of the (overpowered) Fox channel so that my HD HomeRun’s tuner chip could receive it with an acceptable SNR and no dropouts.

The only problem with attenuating my signal was that one of the two PBS channels (8, GPB-HD) was too weak to be picked up through the attenuator.
Continue reading →