Thursday, March 27, 2014

Audio / Visual Morse code Generator for Android

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 expected in this stage. If you found any bugs in this application please let us know via an e-mail.

Saturday, March 22, 2014

Home produced 700VA isolation transformer

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 that reason, make sure to take all the necessary precautions while constructing, testing or using this transformer. Do not try this project if you don’t know what you are doing!

Saturday, March 8, 2014

ATmega169 base 8bit Arithmetic and Logic Unit

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 here.

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.

The Proteus simulation and ATmega169 firmware is available to download at elect.wikispaces.com. This is an open source software project and all the content are licensed under the terms of MIT license.