Sensor Noise (I)

Sensory data is usually noisy unless the sensor itself has a decent built-in filter. However, we can write simple filters to filter out noise. Matlab provides decent filter function, for instance, "filtfilt" for this purpose. I have written a simple filtfilt function working with C or C++ applications, shown in the figure.

Order is the order of the filter function, i.e. zero, first, second, etc. Based on the order coefficients, "a" and "b" are calculated. The simplest way to calculate them is using Matlab "butter" function
, e.g., [b,a]=butter(order, length); For a third order filter coefficients, "a" and "b" are calculated as: [b,a] = butter(3,1/10);

b[0]= 0.0007; b[1]= 0.0021; b[2]=0.0021;
b[3]=0.0007; a[0]= 1.0000; a[1]= -2.6236;
a[2]= 2.3147; a[3]=-0.6855;

PDF Reader/Viewer and Handhelds (I)

FoxitReader Core Engine has been proven to be one of the best performed PDF Rendering Engines. The code base is probably the smallest in the market. Comparing with Adobe, it loads much faster and needs far less memory. Foxit Reader has recently been ranked as one of the top 100 free software by PC World magazine.

"Foxit Reader Named to PC World's "101 Fabulous Freebies' List

http://www.pcworld.com/article/id,124883-page,2-c,freeware/article.html

in Tune Up (Utilities and System Tools)

Foxit PDF Rendering customers include IBM, NEC, Panasonic, Siemens, Microsoft, Xerox, Access, Nero and Lawrence Livermore National Lab etc. Foxit supports all major desktop OSs and the mobile platforms including WinCE, Linux, Brew and Symbian. The embedded WinCE SDK is available in

http://www.foxitsoftware.com/pdf/sdk/embedded/

However, the one time licene cost for research will be $4500.00 and the royalty fee for each application sold will be $5.00.

Python and phones II

For writing Python Scripts for your phone you need to write the script in a text editor. Useful editors are Pywin or ConTEXT, but also notepad works. To learn how to download and install Python editors on your PC see

1. Python .
2. DiveIntoPython and its first chapter
3. An illustrative article to install Python in here

After installing Python and writing the script you need to save it as *.py. The final stage is testing the code, which I found this link very helpful.

Python and phones I

If your phone is Nokia S60 series then you can simply implement simple applications on your phone using script based programming language, call Python. To start you need to download

1) PythonForS60_1_3_23_3rdEd_selfsigned.SIS

2) PythonScriptShell_1_3_23_3rdEd_selfsigned.SIS

from SourceForge (or their latest edition) to your PC. Then connect your phone either via Nokia PC suite or via Bluetooth to your PC or laptop and transfer these two files to the phone and run these files from the phone. Just make sure you install PythonForS60 before PythonScriptShell. For more information about PyS60 see PyS60 wiki.

A helpful link to learn how to uninstall PyS60 or upgrade it can be found here. Or you can simply join Nokia forum.

Peter Cochrane and GPS

I received this article from a friend today about GPS and road map in the UK. I thought this might be an answer to my early complain about poor GPS service close to London on a N95 mobile. See here for more information.

9G Sony-Ericsson Mobile Walkman

Sony Ericsson Mobile Communications will launch late Thursday in Berlin six new phones, including a high-end Walkman-branded handset with around 9G bytes of internal Flash memory, according to a company spokeswoman. More….

In the other hand IPHONE disappoints mobile developers. To hear more about this click here
third-party software developers to create Web 2.0 applications to run on Apple’s forthcoming iPhone. To read more click here This disappointment gets worse when it comes to programming on real mobile phones, i.e., iPhone is planning to provide facilities to

Wait and see which one will win: Apple or Mobile companies?

Mobile Office

In 2000, Fishkin et. al for the first time introduced the notion of “mobile office”. They argued that for a mobile device, such as a 3Com Palm Pilot, users need to be able to produce new data and view and browse the information space via peripheral devices. However current interface design techniques in handheld devices have been copied from large screen design techniques, e.g., Windows Icon Menu Pointer (WIMP). Thanks to John who has forwarded this link to me Future of Smart Phones we see smart phone programmers have started rethinking about mobile application design to improve current bad interfaces. Then later we should wait for a revolution in mobile phones. Treating a mobile phone like N95 as a mobile office is just impossible now. See my early post.