Dilshan R Jayakody’s Web Log

For an amateur radio operator, having a real-time dashboard is essential for monitoring band conditions and identifying DX opportunities. While several solutions exist, I recently completed a project centered on OpenHamClock , an open-source, web-based successor to Elwood Downey’s (WB0OEW) original HamClock . My goal was to move beyond simply opening a browser tab and instead create a dedicated, always-on kiosk for my workshop/shack. This setup allows me to monitor live DX cluster spots, PSKReporter reception, and satellite X-ray flux in real-time, helping me decide exactly when to jump into a radio session. Prototype build of OpenHamClock kiosk. The heart of this project is a two-component system: a centralized server and a remote kiosk unit. For the server, I utilized a PC equipped with an AMD Ryzen 7 series CPU and 32GB of RAM. While this machine hosts multiple other services, it serves as the perfect, reliable host for the OpenHamClock backend. The installation process is...

YALI ( Yet Another LCD Interface ) is an open-source project to provide a universal interface to drive the popular Hitachi HD44780 LCD controller. This module supports 3.3V and 5V MCUs and hardware development platforms, including Arduino, STM32, PIC, and ESP8266. YALI hardware module. The hardware module of this project consists of a 74HCT08 CMOS AND gate and a 74HC595 8-bit serial-in, parallel-out shift register. This module uses the MP1540 step-up converter to power the LCD unit connected to the system. The module has the jumper to select 3.3V or 5V DC power input.  Bottom side of the YALI hardware module. The YALI library is developed using C and is designed to be easily integrated with any C/C++ embedded toolchain. At the initial design stages, this library was successfully tested with all Arduino development boards, NodeMCU , STM32 Blue Pill , etc. The target system must have three digital output lines with 5V or 3.3V logic levels to interface with the YALI module. As m...

This project is about MC3362 and ADF4351 based modularized, 2-meter narrow band FM receiver. In this design, the receiver splits into three modules as RF preamplifier, MC3362 tuner, and ADF4351 oscillator. The RF preamplifier builts around BF900 dual-gate MOSFET. The tuner stage builts using the popular MC3362 , low power narrowband FM receiver IC. For the oscillator, we use the ADF4351 DDS RF signal generator module. The core component of this receiver is MC3362 IC. This IC was designed by Motorola and is no longer in production, but this IC is still available to purchase in many online stores . The chip we used in this receiver was purchased from a local electronic component store for LKR 75 (USD 0.2). The RF preamplifier used in this receiver extracts from the N.Ganesan's (VU3GEK) LRR200, 2-meter band FM receiver project . Prototype version of the RF preamplifier. In this prototype, the above preamplifier was built as a module using a Manhattan construction technique. Th...

This project introduces a digitally controlled 5.1 channel audio preamplifier system. This amplifier is specifically designed to increase the gain of the multi-channel PC sound cards. The main reason for building this amplifier is the limited gain received from the ASUS Xonar AE sound card with the Creative Inspire T6300 , 5.1 surround speaker system. Before switching to this soundcard, we had a Creative Sound Blaster Z card which provided good audio output with the above-mention speaker system. The key motivation of building this amplifier is to solve these gaining problems. The assembled 5.1 preamplifier PCB. This preamplifier consists of six TL074 / TL072 preamplifier stages and PT2258 electronic volume control. The input stage of this preamplifier consists of six TL074 / TL072 buffer stages. The PIC16F886 microcontroller manages the PT2258 electronic volume control IC. All the volume levels and menu options are displayed on HD44780 , 16x2 character LCD screen . All the ...

CLI, also known as Caller ID and calling number delivery ( CND ), is a service offered by the telephone service provider to customers to obtain the calling party number and date/time of the call. The service activation and information format of CLI are different from telephone network operator to operator. CLI display unit - minimum test setup In this project, we will create a small Caller ID decoder using Arduino UNO and a custom-made HT9032D module. The core component of the project is the HT9032D, which can decode incoming call ID data over a telephone connection. This IC supports Bell 202 FSK and ITU-T version 2.3 CLI protocol specifications. The HT9032D module we created here base on the application example given in the IC datasheet . In addition to decoding CLI data, this module also can detect ring signal rises over the phone line. Assembled HT9032D module The Arduino UNO is used to process the decoded CLI data stream and manipulate the LCD. In an idle state, the decoder a...

This post describes our initial attempt to design an automatic Zener diode tester. This tester is designed using well-known ICs such as MC34063 and PIC16F88 . Output for 5.1V Zener diode. This unit is capable of identifying Zener diodes up to 27.5V. Apart from that, it can be used to recognize leads of the diodes / Zeners and detect damaged diodes. For this project, we use components that are already in our inventory. Most of these components can be replaced with more accurate and modern substitutes. This unit provides approximately 5% to 15% accurate readings. Based on our observations, the accuracy of this unit can increase by using resistors with 1% tolerance, stable booster circuit, accurate sampling method(s), and with a more optimized PCB layout. Prototype version of Zener diode tester The schematic, PCB design and firmware of this project are available to download at github.com .

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...

This is an ATmega32 based Proteus simulation of 16 line connectivity tester. I mainly did this project to get familiar with the new Proteus 8 simulator (mainly the new Proteus  - ISIS module). The main functionality of this system is to detect open and short circuits in cables and connectors. This system can test maximum of 16 lines in each test cycle and it indicate the defective line(s) through LCD. This is customizable system and user can configure number of test lines through single push button (SW1). The ATmega32 firmware is developed using WinAVR toolset and it design to work with both simulation and real modes. Schematic of 16 Line Connectivity Tester I never test this system with real parts. If someone interested about real implementation make sure to change RN1 and RN2 to 22K and diode array with 16 - 1N4148 diodes. Recommended supply voltage for this system is 5V DC. This is an open hardware Project and this work is licensed under the Creative Commons Attr...