Monday, January 19, 2015

Sound Transformation with MTG's Spectral Modeling Synthesis Tools

It is Spectral Modeling Synthesis sms-tools of MTG UPF (Music Technology Group, Universitat Pompeu Fabra, Barcelona), by Prof. Xavier Serra (also as instructor in the Audio Signal Processing for Music Applications, Coursera).

Several simple experiments I made.

Friday, January 2, 2015

Simple Workaround Tip for Malfunction Toshiba USB Mouse

Toshiba U20 USB mouse uses only 4 wires. While Logitech uses 5 wires.
In some hardware circumstances (laptop in my case), the Toshiba mouse won't work, it's not detected, keeps blinking and the cursor doesn't move.
This is a simple workaround I tried successfully.

Tuesday, December 30, 2014

Very Simple Yet Effective Dipole Antenna for EVDO 800MHz

One of my mobile broadband Internet provider (EVDO Rev A) planned to close its service in a near future, due to Qualcomm has decided to stop EvDO evolution. The service has real unlimited budget-plan. Currently most of mo-bro providers (both CDMA and GSM) in here are moving to early stages of 4G LTE (either FDD or TDD).

So the impact is, many BTS (base transceiver station) nearby my house have been sold, signal was going worse. Several months ago my EvDO modem (without external antenna) could easily resonated at -70 dBm of HDR power. But since the collapse was announced, signal was suffering at only around -85 down to -90 dBm typically.
(with external antenna, signal can be received at -50 dBm, but I prefer the antenna for another HSPA+ service)

Fortunately I keep an old unused indoor TV antenna. Sure it's dedicated for lower frequency band for TV broadcast. While that my dying ISP works at higher 800MHz of carrier frequency.
Hoho... then I imagined to build a simple dipole antenna to recycle that my old antenna.

Monday, December 29, 2014

MOOC Coursera Certificates

Some of my MOOC certificates (statement of accomplishments). As a matter of memento (personal memorandum).

Tuesday, August 19, 2014

Bubble Clusters Video - Interactive Computer Graphics

"Bubble Clusters" : Clustering algorithm, Bubble's Potential Field algorithm, Iso-Surface & Iso-Line with Marching-Square algorithm.
Assignment #1 of "Interactive Computer Graphics", a course by Prof, Takeo Igarashi, University of Tokyo. 

Wednesday, June 18, 2014

Faster Convolution with Separability Property in Multi-dimensional Signals

Topic: Digital image processing. 

Consider a 2D signal (or impulse response of 2D filter) with rect-shaped.
 This 2D rect signal is separable. It can be represented as dot-product of two independent 1D signals.
As well an impulse signal is also separable.

Monday, February 24, 2014

Mobile Broadband Modem Pointing Using QPST, QXDM

These tools have been already known since long time ago.
Pointing is important to get best signal for our broadband/wifi modem, either with or without external antenna.

(Works only for modem with Qualcomm chipset, and the modem's diagnostic port must be opened.) 


Thursday, January 30, 2014

Basic JPEG Compressing/Decompressing Simulation

Standard JPEG compression uses (1) 8x8 Discrete Cosine Transform, (2) quantization based on certain luminance + chrominance tables, and (3) entropy-encoding (Huffman coding).
Here, I'm using OpenCV (Python) to simulate DCT + quantization + IDCT, without Huffman coding.

Tuesday, January 28, 2014

Friday, December 27, 2013

Basic Processing and Chuck Communication

A very basic example on how to establish communication between Processing and ChucK.
  • run oscProc.pde in Processing
  • run in ChucK
  • in the sketch, press "s" key to send message

Thursday, December 26, 2013

Fast Fourier Transform in ChucK to Get Spectrum

We can convert time domain to frequency domain by using Fast Fourier Transform, that's to calculate the discrete fourier transformation.

This is the basic of finding the spectrum of an input signal, in this case I use a sinusoidal signal as example.
This will display frequencies and power (in polar form of the complex number) at the FFT bin indices.

Tuesday, December 24, 2013

Graph Complex Set In Python with mpmath and matplotlib

In this case I use Python(x,y). This package comes with many standard plugins, such as sympy (in which we use its mpmath), numpy, scipy, matplotlib, and so on.

Simple Processing Game using Minim

This is a simple program (a memory game) written in Processing 2 language.
It has two version, Java mode and Javascript mode.
Using Minim is not straightforward in Javascript mode, especially for sound part. (Yet there is better and richer sound library, Maxim which is until now only be able to play sound in Chrome browser, ref: Can I use Web Audio API ).

Here are both versions,
Java mode:
JavaScript mode:

Electronics Music in ChucK

Following a course by CalArts (wonderful instructors with their expertise on music and computer science: Ajay Kapur, Ge Wang and Perry R. Cook from Princeton ).
It uses ChucK programming language.


Some ChucK codes:

Thursday, November 28, 2013

Using Mobile Hotspot ZTE MF90 With No Battery

Dummy battery from wood + capacitor + resistor.
How to use ZTE MF90 without battery, powering only by electricity power.

Saturday, September 7, 2013

Sierpinski Fractal Basic in Processing


To do: Play around to extend this basic to extended Sierpinski fractal. See these beautiful arts:

Basic b&w:
In color:

Mirror code:

Sunday, June 2, 2013

Coursera, An Introduction to Interactive Programming in Python Videos

My mini-project videos on Coursera course April 2013 - July 2013.
"An Introduction to Interactive Programming in Python"
Instructors: Joe Warren, John Greiner, Stephen Wong, Scott Rixner
Rice University.

(View the videos in Youtube for better experiences.)

Saturday, October 22, 2011

Google Plus API Java Starter for NetBeans IDE

 This is my personal notes on porting following described package into NetBeans IDE. CMIIW is one of my gods. This is written in 2011, hence it might or might not work with latest update (if any). 

Google Plus Java Starter is a very basic example starter package to learn Google Plus API client for Java. Unfortunately it does not include package for NetBeans IDE (it prefers Eclipse as I guess it due to Oracle factor). 
Here is explanation on how to port starter code into NetBeans IDE 6.9 (Microsoft Windows OS environment).

Credits to google-plus-java-starter project people:
They are team member creating original starter package.

Google App Engine Java SDK

Thursday, October 20, 2011

Google+ API Activities using HTML and JQuery

 My personal note. (CMIIW is one of my gods). This is written in 2011, hence it might or might not work with latest update (if any). 

This is the very basic and simplest example to access Google+ activities via its API, using HTML, JQuery and simple API key authentication.

All client side scripts. There is no server side scripts is being involved.

The only weakness of the codes is: I need to hide my API key somewhere in the server's inaccessible folder.
But it can be overcame when I use the code in real application, by deploying the HTML file into a web server.

Since it's contained in a HTML file, it can be utilized in non-native mobile application, such as HTML5 app runnable in mobile devices. I also imagine blog (Blogger, Wordpress) sidebar-plugin and browser's add-ons.