Dilshan R Jayakody’s Web Log

RDRAND is an instruction to return random number from new Intel CPUs. This is NIST SP 800-90A compliant random number generator and now this instruction is a part of IA-32/IA-64 instruction sets. RdRand instruction is available from 3 rd generation Intel Core i5 and Core i7 processors. RdRandLib is lightweight DLL to generate random numbers based on RdRand instruction. This library contain signal function to generate one or many random numbers and sample codes are available for C/C++, Delphi, Lazarus and C# languages.  RdRandLib source codes and sample codes are available at http://github.com/dilshan/rdrandlib . Compiled version of DLL is available at http://github.com/dilshan/rdrandlib/releases page.

Analog AC line monitoring box This is a quick post about our newly constructed AC line monitoring unit. This unit consists with analog AC voltmeter, frequency meter and ammeter. Both voltmeter and frequency meter are 2.5 × 2.5 inch in size and ammeter is 3.5 × 3.5 inch in size. All these panel meters are commonly available in market. Ammeter in this assembly is connected to the mains line through 60A – 5A current transformer and all the other panel meters are coupled to the mains line through 100mA quick blow fuses. Wiring diagram of this unit is illustrated in below. Wiring diagram of analog AC line monitoring box Enclosure of this assembly is made with medium density plywood sheets. All the internal mains line of this unit is wired using 2 × 12 SWG copper wires. We construct this unit to monitor the AC line status continuously and also to get some line measurements accurately (from known reference level). In our version of line monitor all the AC line connectors c...

This is high quality stereo digital audio amplifier with PLL synthesized FM radio receiver. Some of the high level specifications of this receiver are listed in below: Audio output power: 4W + 4W (with 8ohm speakers) Input sources: FM and 3 external stereo line inputs FM frequency range: 88.00MHz – 108.9MHz Supply voltage: 12V – 15V (2A current source is recommended) Tone control options: Bass, Treble and Loudness control Bass / Treble boost: 14dB Bass / Treble cut: 14dB Station memory: Preset 10 FM radio stations FM tune options: Auto and Manual with 25 kHz steps Key components of this audio system are ATmega32A - 8bit microcontroller, TT502 ( TEA5767 ) stereo FM radio module, PT2314 audio processor and μPC2002 audio power amplifier. This system is design to work with 12V - 15V (2A) DC power source and KA7632 multi-output regulator is used to manage power requirements to the above mentioned components. Prototype version of digital audio amplifier User interfa...

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 .