Dilshan R Jayakody’s Web Log

This is demonstration project to control servo motor movement using physical marker and normal video camera. In this project video camera capture the movements of marker and calculate rotation angle based on that. This calculated rotation angle is feed to the servo through small MCU based interfacing unit. In this project video processing and tracking is performed using ARToolkit and controlling of servo is carried out using PIC16F628A microcontroller. RS232 interface is use to communicate between PC and microcontroller. Interfaces in optical servo controlling system This application detects movement of marker on Z axis (yaw) and transforms it into another numerical scale to manipulate the servo motor. Processing application is written using Visual C++ and configured to work on Windows operating system(s). The marker used for this application is needed to be a " square with some symbol " and user can train this system for any compatible marker. As per our tests, st...

This article introduces high quality digitally controlled 2.1 channel analog audio power amplifier system. This project is mainly based on TDA7377 AF power amplifier and PIC18F452 8bit microcontroller. Basic features of this receiver are 2 × 6W + 20W audio output power, ±14dB bass and treble controls, fully configurable +35dB bass booster for sub-woofer and satellite speakers and loudness switch. This system use commonly available electronic components and all the integrated circuits are in DIL packages. This amplifier consists with few UI elements such as 2 push buttons and 1 rotary encoder. All the menu navigation can perform through rotary encoder. Prototype version of 2.1 channel audio power amplifier project Entire amplifier can build on 147mm × 80mm PCB and all the PCB design files are available to download at google drive . This is an open hardware project and all the firmware source codes, design files are covered with Mozilla Public License version 2.0 . All the ab...

I got Trio ( now Kenwood ) JR-310 and TX-310 SSB receiver and transmitter pair recently. When it comes to me both receiver and transmitter are in very bad shape and most of the PCBs and chassis are covered with dust and some of the components are very badly damaged. After examining both the chassis I decided to repair both units because of its vintage value (and also I like to try some tube base SSB receiver and transmitter pair). Trio JR-310 is AM, SSB and CW mode HF receiver. This receiver has 3.5, 7, 14, 21, 25 and 50MHz operating bands and sensitivity is around 1µV. This receiver consists with 6 vacuum tubes, 5 transistors and 19 diodes. JR-310 which I restored is working with 110V and total power consumption is around 70W. Bottom view of restored JR-310 receiver TX-310 is 20W SSB transmitter and designed to match with JR-310 receiver. It is capable of LSB, USB, AM and CW transmissions in HF bands. This unit consists with 10 vacuum tubes, 5 transistors and 9 diodes. Like ...

Recently I got vintage Eddystone EC10 MK1 communication receiver from friend of mine and it is completely dead when it comes to me. EC10 MK1 is one of Eddystone's very early solid state communications receivers and it use 10 PNP Germanium transistors. This receiver cover 550 kHz to 30 MHz and come up with BFO for CW and SSB receptions. Restored EC10 MK1 HF communication receiver The main problems which I noticed in my EC10 is corroded wires, components and PCB. I did restoration step-by-step and most of the steps are listed in my qsl.net page . Other than repairing, this article covers details of power supply which I integrated into EC10 communication receiver. The schematics and photographs are available at the same article . After repairing and above changes EC10 starts to work again and with some external antenna is performs quiet well. Most of the times I use this receiver to listen to 40m 4S7RS net on 7060kHz.

Panasonic RX-5090T is quiet old combo box from Matsushita Electric and its most notable feature is powerful three band SW tuner. Recently I got some RX-5090T unit and its problem is distorted audio output. PCB and mechanical component distribution of Panasonic RX-5090T combo box After careful examination we identify C128 (100 µ F / 10V) and C224 (3.3 µ F 25V) as defective components. In this unit, VR103/203 (20K Ω ) potentiometer is also defective and because of that we got some random distortions when we try to change the volume of the receiver. To fix this issue we disassemble the potentiometer and clean it using isopropyl-alcohol (this potentiometer is not available in local market and only option is to clean it and use it again). After these two fixes receiver starts to work again. Mainboard of Panasonic RX-5090T combo box Schematic diagram of Panasonic RX-5090T is quiet difficult to find in the web and we share copy of it in here .

This is our first vacuum tube base amplifier project and this project is based on 6AS5 pentode and 6N2P dual triode. Schematic of this project is not designed by us and we got it from web. We got this schematic sometimes ago and now we can't find original site where this schematic appeared first, because of that we host copy of that schematic in here . Prototype version of 6AS5 and 6N2P guitar amplifier In original schematic, initial stage of the amplifier is based on 12AX7 high gain tube. During the construction we can't find 12AX7 in local market and because of that we replace 12AX7 with 6N2P. Both 12AX7 and 6N2P had identical characteristics and only major difference is heater configuration. After replacing 12AX7 with 6N2P, both the tubes can drive through single 6.3V filament supply. 6N2P tubes are now commonly available and we use Russian version of 6N2P (6Н2П) for our testing. We test this amplifier with 4K audio output transformer and it produces excellent ...

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.