GPS and WiFi combination

Being interested in GPS topics, I've spent a few hours on Internet reading about the current available solutions. As I was browsing the pages, I've came across the Description of positioning systems. My curiosity has been directed towards Skyhook Wireless' Navizon - a software solution that allows mobile devices to access online database of positions of WiFi access points around urban areas of cities. For a mobile WiFi enabled device that is able to capture MAC of any access point, it becomes a matter of pointing down a known location of that device on a map stored locally. New maps can be uploaded to Skyhook's server updating the locations of moved APs. Likewise, maps can be easily downloaded to a portable device, allowing offline browsing.
In the absence of APs, GPS locator can take the lead. On the other hand, when GPS signal is low (places like buildings, tunnels), WiFi will kick in. The best part about it is that there is no need for Internet connection - MAC addresses are transmitted by APs for free!

In my understanding this is a great solution, providing the following:

• Maps can be downloaded whenever one has an Internet connection
• MAC broadcasting feature of APs can be exploited to determine one's position
• Can be combined with GPS receiver (use software to switch between WiFi and GPS)
• GPRS can be used whenever one cannot download maps via WiFi (i.e not available)
• Central database is updated by thousands of users automatically

One thing that is interesting to mention is the following. If a location of MAC address of some bogus device that is constantly moved around the city is uploaded to a server, it might create confusion because it can be detected by a mobile device in a different location and create the wrong sense of position, especially if it's the only or one of few APs around the area. Now, of course the software should be smart enough to detect the change and warn the user of inconsistency. All the user have to do is move and discover more APs.

Related:

RF Fingerprinting in Wi-Fi Location Tracking

Hardware projects

Dev/Project related
Dev board with a microcontroller

Gadgets, ideas, DIY electronics links
OpenSource gift guide
The Time Fountain (really cool fountain project, which uses strobe light to "freeze" or slowdown and reverse the motion of fluorescent drops).
Lucid Dreaming Mask (by the author of The Time Fountain. He claims his inexpensive hardware triggers lucid dreams... thought I might add this here since I've spent some time reading the experiment).
Hacking Roomba robotic vacuum cleaner

Photoshop classics

Some cool photoshopped classics:

Coffee, Reach, McDavid, Raid

Inexpensive Arduino microcontroller dev/project board

Parallax’s Basic Stamp is the mainstay for hobbyists wanting to add intelligence to everyday devices. A new system called Arduino provides the benefits of the Basic Stamp at a greatly reduced cost, increased speed, and is entirely open-source. (http://todbot.com/blog/2006/09/25/arduino-the-basic-stamp-killer/#more-121)

Mobile Processing

Mobile Processing is an open source programming environment for people who want to design and prototype software for mobile phones. It is based on and shares the same design goals as the open source Processing project. Sketches programmed using Mobile Processing run on Java Powered mobile devices. (http://mobile.processing.org/index.php)

Configurable Processors

In this article, Steven Leibson from Tensilica shows some tricks used to hardware-optimize DSP computations with the help of SoC, FGPA, or ASIC. He emphasizes that the use of hardware acceleration is crucial for many DSP applications. Adding special instruction extensions supported by configurable hardware has advantage over assembly-code optimization of a critical path of an algorithm.

There are a few examples (MPEG4, Viterbi and FFT).

http://www.dspdesignline.com/howto/showArticle.jhtml?articleId=193302782&pgno=1

Tcl - How to pass arrays

from wiki: (http://wiki.tcl.tk/3262) and newsgroups.

Tcl does not provide a way to simply pass arrays by value, as this is usually done for strings. Straigh forward way to go around this problem is to convert an array to list and pass it as list. Another method is to use upvar to pass variable by name. Some other methods are mentioned below:

• Use dict command instead of array (for Tcl 8.5 or greater)
• Use extensions:
• Tclx keyed lists.
• the structure command from the megapkg structure extension.
• ...

Removing Low Disk Space Checks (Windows XP)

That's it! It finally pissed me off to the point where I went online and found the way to disable that Windows' popup message to remind you that the disk space is low. I know myself when I am close to zero since I am the one who is filling up the hard drive. I agree that this message might be helpful to some newbie Windows users; however, I also believe that there should be a gui option to disable it - for those who do not touch registry too often and also who do not want the message to appear.

Here is how you can do it.

1. START -> Run...
2. Type 'regedit' and hit Enter
3. In regedit application, go to HKEY_CURRENT_USER -> Software -> Microsoft -> Windows -> CurrentVersion -> Policies -> Explorer
4. Create a DWORD value named "NoLowDiskSpaceChecks"
5. Double-click it and set its value to 1.
6. I haven't seen the message since then (Windows might need to be restarted first)

Update: Found another easy solution in one line. Read at Downloadsquad.

Usenet Etiquette

I've been using news groups for quite a while now. Out there people are quite picky about the format the messages are submitted in. Since there are a lot of 'newbies' in this area, there are quite a few webpages summarizing Usenet Etiquette. If you are not using it, once in while you'll get slapped back with a message suggesting you to do so, which becomes annoying in a sense as well. In my opinion, most of them make sense, giving you a better efficiency and making your point clear to everyone.

Here are couple of guides. If you go to one page, most likely it will link you to another one.

• Why is Bottom-posting better than Top-posting
• The art of Quoting (good manners in posting on Usenet)

Ubuntu - Mounting Windows Partitions

Here is a nice guide how to mount NTFS and FAT32 partitions under Ubuntu: http://www.psychocats.net/linux/mountwindows.php

Ubuntu 5.10 - Cleaning up the space

Here are some some ideas how to clean up the space.
1) Run the following command:
sudo apt-get clean

2) Clean up synaptic's downloaded files

3) To estimate file space usage, change directory to root and use du command:
cd / sudo du -hc --max-depth=1 
Here is example of what is printed for me:
48K     ./lost+found
14G     ./media
36M     ./etc
76M     ./var
90M     ./lib
2.4G    ./usr
4.0M    ./bin
7.7M    ./boot
2.9M    ./dev
732M    ./home
4.0K    ./mnt
507M    ./proc
23M     ./root
8.4M    ./sbin
72K     ./tmp
0       ./sys
4.0K    ./srv
4.6M    ./opt
4.0K    ./initrd
4.0K    ./debootstrap
4.0K    ./_F
1.4G    ./_D
4.0K    ./_C
37G     ./_E
2.1G    ./_sky7
12K     ./Xilinx
58G     .
58G     total

Useful FireFox Plugins

Today I came across a webpage that gives you some advices on essential extensions for FireFox browser. Here it is:
http://www.linuxpipeline.com/showArticle.jhtml?articleId=177104614&pgno=1

Some of the useful addons mentioned there are:

• Disable targets for downloads
• Tab Mix Plus
• Search Plugin Hacks
• History Menu
• Adblock Plus
• and Adblock Filterset.G Updater
• FasterFox

Updated (Oct 22, 2007):
The other ones I use are:

• del.icio.us buttons
• del.icio.us Bookmarks
• All-in-One Sidebar
• BlueOrganizer
• Email This! Bookmarklet Extension
• SmartLinks
  

Intro

Intead of keeping paper notes and updating Favorites of an internet browser, I've decided to keep an online version of the things I find out on the Internet, useful tweaks and anything relevant to computers and technology here, in one spot - not only for my personal use, but also for people who might find it useful.

lomtik