Dilshan R Jayakody’s Web Log

Workshop Organizer is light-weight, cross platform inventory controller for home-workshops. This application is specifically design to manage electronic/electrical components at home-workshops, but it can use to manage other areas of workshop including tools, machinery and mechanical components, etc. To store data, this application use SQLite database system and all the necessary runtime libraries for SQLite is available with the “Workshop Organizer” package. User may not need to download or install separate SQLite database system to use this application. Workshop Organizer default SQLite database consist with more than 600 reference data including list of manufacturers and types. Workshop Organizer 1.0 on Windows 8.1 operating system “Workshop Organizer” is a native mode application and user may not need to install any framework to use this application and compiled binaries are available for both Linux and Windows operating systems.  All the project sou...

This is high quality audio power amplifier which we constructed for our audio related experiments. This amplifier is based on NXP’s TDA1521A integrated circuit and it is capable to deliver 2 × 6W audio output power with 20V - 25V asymmetrical power source. The design of this power amplifier is heavily based on the schematic provided in the TDA1521A datasheet. As an addition we incorporate headphone output option to this design. Connection diagram for TDA1521A Amplifier PCB PCB which we designed for this amplifier is 55mm × 65mm and it need separate power supply to drive. For optimal results use this AF amplifier with 12V – 20V regulated DC supply and with 4 Ω full range speaker pair. PCB, schematic and wiring diagram of this project is available to download at google drive .

Morse View is an open source software project to convert audible Morse codes to text messages. This application is capable to convert Morse codes from wave files or from the audio line/microphone inputs. Conversion from Morse code to text can perform based on amplitude and frequency decomposition of the input audio stream. Morse View decoding 25 WPM Morse code wave file We extensively test this application using Morse code files available at ARRL - W1AW code practice page . During the testing we may be able to use this application to decode 5WPM – 40WPM Morse code inputs. As per our test result, after 25WPM, accuracy of the decoder is heavily depends on the quality of the sound card / audio capture device (ADC) and with the system configuration. We test this system with few audio adapters, and out of those adapters both Creative Sound Blaster X-Fi and VIA VT1723 generate more accurate results, especially on 25WPM – 40WPM range. We test this software with different noise c...

This 300V AC/DC variable PSU is designed for our vacuum-tube, MOSFET and some IGBT related experiments. This PSU consist with 0-300V Variac (variable auto-transformer), 700VA isolation transformer, which is described in previous blog post and high voltage AC-DC converter. Because of the size and weight of these equipment’s we build this PSU as three separate units. Complete view of 300V AC/DC variable power supply unit. This PSU is capable to supply 20V - 300V 2.3A (max.) output in either AC or DC form. This PSU use high voltage and because of that, all the proper construction and precautions are necessary to take. Improper wiring or construction may leads to lethal electrical shock and/or fire. If you are not familiar with high-voltage practices do not attempt this project at home. Schematic of this PSU is available to download at google drive .

This is an Android application to send Morse code messages using tones or flash (light) signals. This application supports for basic Latin alphabet, Arabic numerals and it can transmit messages with specified speed which can vary from 100ms to 500ms. Main application view  This application is developed using Delphi XE5 and it supports for Android version 2.3.3 ( Gingerbread ) to 4.2 ( Jelly Beans ) except Android version 3.2 ( Honeycomb ). This application is specifically design for 3.4 inch - 5.0 inch Android smartphones and we tested this application with few Huawei , Samsung and HTC devices. Audio / Visual Morse code Generator is an open source software project and its source code is available at http://github.com/dilshan/signalman . Compiled package is available to download at http://github.com/dilshan/signalman/releases . This project is distributed under the terms of MIT license . Delphi Android compiler platform is still evolving and some bug can be expecte...

This a quick post regarding homemade 300V - 2.3A isolation transformer. This transformer is a part of my ongoing 300V AC/DC variable power supply project and it’s boxed as a separate unit because of its heavy weight and size. 700VA isolation transformer with enclosure All the parameters of this transformer are calculated using small Python script which I was written sometimes ago. This script support for step-up, step-down or 1:1 power transformer windings and it can execute on any platform where Python 2.7 (or newer version) is supported. In isolation transformers separation between primary and secondary windings is an important factor. In this transformer I use multiple layers of 3M Scotch Electrical Insulation tape as primary and secondary winding separator. Standard 50mm PVC electrical insulation tape is used to cover secondary winding of this transformer. Improper connections or construction of this transformer may leads to fire or lethal electrical shock. Because of...

ALU (Arithmetic and Logic Unit) is a digital system that performs integer arithmetic and logical operations. In this post we introduce ATmega169 base ALU simulation using Proteus . This is 8bit ALU, and functionally it is similar to other entry level ALUs such as Motorola MC14581, 74LS181, etc. This unit can perform 80 arithmetic and logic operations and all these operations are listed in below of this post. schematic of ATmega169 base 8bit ALU simulation Firmware of this ALU is developed using AVR-GCC. While at the development we try to isolate firmware with platform as maximum as possible, because of that, this firmware can be modified to run on top of PIC , 8051 or MSP430 MCUs with minor set of changes.