Friday, August 22, 2014

Batch Processing of Images in GIMP

To perform batch processing of images in GIMP, you can get a plug-in called David's Batch Processor at the link - http://members.ozemail.com.au/~hodsond/dbp.html. Extract the dbp.exe file and put it at C:\Program Files\GIMP 2\lib\gimp\2.0\plug-ins. Then, open GIMP and click Filters menu -> Batch Process... command. A pop-up windows - David's Batch Processor will appear as shown in the following figure and you can do the batch processing that you want.

Saturday, August 16, 2014

Selective Color Modification

I wanted to change the blue color of the road in the following picture to a green color. I wrote a MatLab program and run it in Octave. Although I can simply use rgb color model to swap blue and green, I feel like it is too specific. That is why, I used hsv color model to change a hue of a color in a more flexible manner.

Thursday, March 6, 2014

Reading Rotary Encoder Using Microcontroller

Rotary encoders are commonly used for measuring angular position or motion sensing. An optical encoder has a disc with a pattern of cutouts. As the disc rotated, an LED light that shines on photo detector is turned on and off accordingly to produce a digital waveform.

An optical encoder produced by VEX Robotics Design System

Gray code is normally used in encoders instead of ordinary binary code to prevent glitches. In Gray code, the number of changing bits between successive numbers is only 1. The following table shows 2 bit Gray code from 0 to 3.

Sunday, December 1, 2013

Myanmar Astrological Calendar Days

A typical Myanmar calendar usually describes astrological days such as auspicious days and ill fated days. In this post, we will present about the following days and javascript code for them.

Monday, July 8, 2013

CAN bus

CAN bus (controller area network) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other. CAN bus is a message-based protocol, designed specifically for automotive applications but now also used in other areas such as aerospace, industrial automation and medical equipment. The advantages of CAN bus compared to RS232 communication are as follows.

Friday, June 28, 2013

Using Analog to Digital Converter of AT89C51CC01 Microcontroller

Using AT89STK-06 starter kit, I have written a few C code to read an analog to digital converter (ADC) input of AT89C51CC01 which is an 8051 microcontroller. It has 8 multiplexed ADC inputs with 10 bit resolution. As an example, ADC input pin 7 which is connected to a variable resister is read.

GNU Octave as an Alternative to MatLab

GNU Octave, FreeMat and Scilab are free open source software for numerical calculations alternative to MATLAB. After reading reviews in the Internet, I chose GNU Octave to try. Installing GNU Octave on a Windows system is easy. Download the files from its Download page and extract them to a folder. Then, you can put the shortcut at a desired location and change the path and the icon in its properties. When you open GNU Octave by clicking the shortcut, a window will appear as shown in the following figure. You can key in MATLAB commands there directly.