Archive for the ‘Hardware’ Category

 

bigclivedotcom Youtube channel

bigclivedotcom is a Youtube channel operated by Clive from Isle of Man. He dissects and investigates all kinds of electronics stuff, mostly ordered from questionable eBay sources. If you are into electronics this is a really enjoyable channel.

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Posted by on March 2nd, 2016 No Comments

Vivotek PT7137 rtsp stream to webpage using VLC plugin

One way of getting the video from Vivotek PT7137 to a webpage is by using the VLC plugin and connect the rtsp stream.

However, in current version of Chrome the VLC plugin is no longer supported. Instead it is suggested to use HTML5 to embed video, but rtsp is not supported in Chrome so it is kind of a dead end there for the moment. This solution works in for example Firefox.

In the webpage where you would like to add the stream:

<object classid=”clsid:9BE31822-FDAD-461B-AD51-BE1D1C159921″ codebase=”http://download.videolan.org/pub/videolan/vlc/last/win32/axvlc.cab” id=”vlc”>
</object>
<embed type=”application/x-vlc-plugin” pluginspage=”http://www.videolan.org” autoplay=”yes” loop=”no” width=”600″ height=”340″ target=”rtsp://USERNAME:[email protected]:554/live.sdp” />

Replace USERNAME, PASSWORD and IPADRESS with real values for your Vivotek PT7137 camera. It might be a good idea to create an account in the Vivotek PT7137 to use from the web as the username and password will be visible for anyone who inspects the webpage source code. That said, putting the root user account and password here would be considered stupid 🙂

Tip for Joomla users: If you include this code in a Joomla site, include {emailcloak=off} before the above, because the @-sign will trig Joomla email cloaking beliving it is an email address.

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Posted by on December 8th, 2015 No Comments

QNAP TS-420 web interface not accessible over SSL

After a reboot the web interface on a QNAP TS-420 NAS was not accessible over SSL. A nmap showed the NAS was not listening on the SSL port and it was configured to force SSL connections over the standard 443 SSL-port. So trying to access it over the non-SSL port just directed me to https://<ip-address of the nas> where there was no response.

To be able to access the web interface over the non-SSL port 8080 i had to ssh into the NAS using the admin account, then I issued the following commands:

/sbin/setcfg SYSTEM "Force SSL" 0
/etc/init.d/thttpd.sh restart

After this it was possible to access the NAS web interface over the non-SSL port, i. e. http://<ip-address of the nas>:8080

 

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Posted by on November 21st, 2014 1 Comment

Improving wifi in a crowded wifi environment

This is a litle trick I use when I travel and hook up to a wifi network in a crowded wifi environment. Sometimes the network performance over wifi is really bad and the problem is that it can be caused by heavy traffic (like file sharing) on another wifi network sharing the same channel as yours. I have experienced this especially when travelling to big cities like Paris, Amsterdam and so on. First of all, it is recommended that you disable 802.11n wifi mode which works terribly bad in crowded environments. See this article for Windows and this for Linux (Ubuntu).

 

Crowded wifi environment (Wifi Analyzer for Android)

Crowded wifi environment (Wifi Analyzer for Android)

The problem with the wifi technology is that networks in the neighbourhood is sharing the same channels. In the 2,4 GHz band there are only 11-14 channels availible (depending on your region) and those channels overlap. That means if your network is on channel 1 you will get interference with traffic on channels 1, 2 and 3. Another problem with wifi is that is has no means of evenly dividing the capacity (like timeslots), so it is kind “the one shouting highest gets the most bandwidth”. And when someone already is using a lot of bandwidth (like file sharing) it is very hard for other users to obtain a part of the bandwidth. Even if it is the neighbours wifi which you can’t access but it shares the wifi channel.

A countermeasure to improve the situation is to constantly use some bandwidth forcing the heavy users to pull back a bit. Before transmitting, each node in the network listens in the air if the channel is free, so by using a little bit of bandwidth even if idle you don’t give the other node the same possibilty to hog the entire capacity.

First of all, find out the IP address of your local network default gateway. In WIndows you run a command prompt (cmd) and type the command ipconfig. In Linux you can use netstat -rn.

To constantly use up a small portion of the bandwidth I use the ping comand. Ping normally sends very small packets (56 bytes), but to get this to work we need a bit larger packets (but not to large, then we will hog the entire capacity). 1024 bytes is good.

In Windows you run the command (replace 192.168.0.1 with the IP-address of your local network which you found out above):

ping -t -l 1024 192.168.0.1

and in Linux you run:

ping -s 1024 192.168.0.1

 

ping with 1024 bytes

ping with 1024 bytes

Voila! Now my wifi connection gets a lot more stable because I force the other wifi nodes to pull pack a bit since I constantly make them aware of my presence.

 

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Posted by on May 27th, 2014 No Comments

Disable 802.11n on Compaq 6910p with iwl4965 in Ubuntu

I’ve found out that the 802.11n high speed wifi / wlan mode (300 Mbps theoretically) tends to cause more harm than good, i.e. the performance in many, especially crowded, wifi environments will be really poor and it is a better option to turn it off. 

My Compaq 6910p laptop comes with an Intel Wireless WiFi Link 4965AGN chipset. The 802.11n mode can be disabled making it fall back to only use 802.11a/b/g modes casuing the connection to be much more stable and often the overall bandwidth will be better. 

To check if your chipset is running with 802.11n enabled, enter the command:

sudo iwconfig wlan0

The output will look something like this:

wlan0     IEEE 802.11abgn  ESSID:"XXXXXX"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:0C:F6:82:90:28   
          Bit Rate=14.4 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=51/70  Signal level=-59 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:66  Invalid misc:36   Missed beacon:0

If the first line says 802.11abgn your chipset has 802.11n activated.

To disable 802.11n mode do the following:

sudo modprobe -r iwl4965
sudo modprobe iwl4965 11n_disable=1

This will disable 802.11n until next reboot. Now check again with sudo iwconfig wlan0 and the output should display the first line without the "n" after 802.11, like this:

wlan0     IEEE 802.11abg  ESSID:"XXXXXX"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:0C:F6:82:90:28   
          Bit Rate=54 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=46/70  Signal level=-64 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:7  Invalid misc:485   Missed beacon:0

If you want to make this change permanent, i.e. always disable 802.11n, do the following:

sudo echo "options iwl4965 11n_disable=1" >> /etc/modprobe.d/iwl4965.conf

After rebooting, verify using sudo iwconfig wlan0 that 802.11n is not enabled.

 

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Posted by on April 24th, 2014 1 Comment

Samsung Ultrabook series 5 loses wifi connection intermittently

On a rather new Samsung Ultrabook series 5 we had intermittent / sporadic connection problems on some wifi networks. The status for the network shifts forth and back between ok and "No internet access". This doesn’t happen on all wifi networks. It seems the problem is the 802.11n mode, especially in a crowded wifi environment.

The solution (or workaround) is to disable the 802.11n mode in the wifi driver for the Intel(R) Centrino(R) Advanced-N 6235 chipset. This gives a lower bandwidth connection but on the other hand, a stable connection.

  1. Go to the Control panel
  2. Open Network connections (search for it if you have troble to find it)
  3. Right click on your wifi connection and select Properties
  4. Click Configure in the upper part of the box (my screenshot is danish, so it is the button labeled "Konfigurer…")
    Intel Centrino Advanced N-6235
  5. Click on the Advanced tab
  6. Find the 802.11n mode status configuration parameter and select to set it inactive (off)
  7. Click Save / OK in the bottom 

 

 

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Posted by on April 16th, 2014 1 Comment

[Solved] Samsung Galaxy Note II (GT-7105) + Plantronics Voyager Legend bluetooth headset poor audio quality

I recently bought a Plantronics Voyager Legend headset to use with my Samsung Galaxy Note II phone. It worked fine for a day or two, then I started to experience poor sound quality. Especially the person I was talking to had real trouble hearing me. Restarting bluetooth in the Samsung or restarting the Plantronics headset did not help. But restarting the Samsung Galaxy Note II resolved the problem momentarily – after a day or two the problem returned.

Before returning the headset to the dealer I decided to have a look at Plantronics website and found out there are a firmware update procedure availible on their website. To get the update software running on my Windows 8 PC I had to run the installer as administrator. When returning to the update window in the browser (yes, the update procedure is done all in the browser), I found my headset was running firmware version 44 and an update would update it to version 93.

After updating the firmware all quality issues where gone. 

To update the Plantronics headset visit http://www.plantronics.com/us/support/myheadset/updater/

 

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Posted by on October 15th, 2013 No Comments

HP Compaq 6910p builtin 3G modem driver for Ubuntu

From Ubuntu 11.04 and onward there is no need for a driver to use the builtin 3G (WWAN) modem in the HP Compaq 6910p laptop computer. But by default the modem is soft blocked even though the radio lamp is on. The rfkill utility can be used to enable it:

$ rfkill list
0: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
2: hp-wifi: Wireless LAN
Soft blocked: no
Hard blocked: no
3: hp-bluetooth: Bluetooth
Soft blocked: no
Hard blocked: no
4: hp-wwan: Wireless WAN
Soft blocked: yes
Hard blocked: no

Enable it with rfkill unblock 4

$ rfkill unblock 4
$ rfkill list
0: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
2: hp-wifi: Wireless LAN
Soft blocked: no
Hard blocked: no
3: hp-bluetooth: Bluetooth
Soft blocked: no
Hard blocked: no
4: hp-wwan: Wireless WAN
Soft blocked: no
Hard blocked: no

Now click on the network manager icon in the top right bar of the screen and Activate mobile broadband and off you go!

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Posted by on August 12th, 2012 No Comments

Improving Firefox performance on ASUS EeePC 900

I’ve noticed that a bottleneck in Firefox performance on the ASUS EeePC 900 is writing and reading to the disk cache. It is often I wait for something on a page and I notice that the hard disk light is on indicating read/write.

One way of drastically improving the performance is to move the cache to a ramdisk as the built in flash disk in the EeePC is not the quickest one on the block. This way you might also prolong the life of the flash disk as you decrease the number of read/writes to it. The only drawback with this is that you will loose the cache content between reboots, but I don’t think that is a problem. If you have extended your machine’s ram to 2 GB (se another post about that), you have memory to spend for this, but it will probably work on 1 GB machines too.

If you are running EasyPeasy (probably in other distros too) you already have a ramdisk. Check by starting a terminal and enter the df command. If you see "/dev/shm" you have a ramdisk. Otherwise, you first need to create one (Google might be your friend in this case).

  1. Start Firefox and in the URL-bar, type about:config and press enter. Click yes on the warning about this being very dangerous.
  2. Find the key browser.cache.disk.parent_directory and right click to select Modify. If the key is not present, you right click in the list, select New -> String and type browser.cache.disk.parent_directory
  3. As the value for the key, enter /dev/shm
  4. Pull down the Edit menu and click on Settings
  5. Click on Advanced and select the Network tab
  6. Select the Override automatic cache handling and limit the cache size to for example 100 MB (so the cache won’t eat all your ramdisk).
  7. Close all Firefox and restart it.

In my case, this drastically improved the Firefox performance. 

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Posted by on August 12th, 2012 No Comments

ASUS EeePC 900 2 GB memory upgrade

The ASUS EeePC 900 is a dear friend of mine and has served me truly for a number of years. It is not my primary work horse, but on trips it is excellent with it’s small size and low weight (even on a 14 day trip I always travel with hand luggage only). It is also a comfort when travelling to know that I am not carrying an expensive piece of equipement. This little fellow has been my travel companion to many different countries – near and far away. So I really don’t want to retire it and recently I decided to "pimp it" a little. When running a couple of applications it quickly consumes the 1 GB of RAM, so a little bit more wouldn’t hurt.

It ships with 1 GB of RAM installed and it is possible to upgrade it to 2 GB. It is actually a question of replacement rather than expansion due to the fact that there are no free memory slots. The upgrade is performed by replacing the 1 GB SODIMM with a 2 GB SODIMM.  

For specifications of the ASUS Eee PC 900, see this wikipedia page.

The memory module needed is a DDR2-400 SODIMM but 533 and 667 MHz will also work. I used a Crucial 2GB DDR2 PC-5300 667 MHz CL5 SODIMM. Note that memory modules are sensitive to static discharge. Preferrably you should at least have a grounding wrist wrap or even better if you have access to an ESD secure work place. In reality most of us will just rely on the kitchen table and being careful not to touch any connectors or metal parts of the memory module. That will also work in most cases 🙂 

  1. Unplug the power cord and remove the battery. 
  2. The memory module is hidden behind a hatch on the bottom of the PC. The hatch is secured with two screws, one hidden behind a EeePC label (possibly acting as a warranty void seal). Remove the two screws and the hatch. 
  3. Remove the preinstalled 1 GB SODIMM by pulling locking plates on the sides a bit apart until they release the module.
  4. Insert the new 2 GB SODIMM and make sure it locks by pushing it gently down until the locking plates clicks into position.

  5. Reinstall the latch and the two screws.
  6. Install battery and connect power cord.
  7. Say your prayers, press the power button and hopefully your EeePC boots up so you can enjoy your brand new 2 GB of RAM!

 

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Posted by on August 9th, 2012 No Comments