Dilshan R Jayakody’s Web Log

This project focuses on a simple yet powerful FM stereo tuner module. The core component of the module is RDA5807M , a single-chip broadcast FM stereo tuner that has gained popularity among designers in recent years due to its high level of integration. This integration significantly reduces the need for external components, simplifying circuit design. The RDA5807M supports a wide FM band, covering frequencies from 50MHz to 115MHz, making it adaptable to global FM standards. Additionally, its use of a low-IF digital architecture streamlines the design process by requiring fewer external parts. The inclusion of an AGC (automatic gain control) feature ensures consistent signal reception, even in environments with fluctuating signal strengths. FM stereo receiver module with seven segment module. The chip's digital stereo decoding capabilities deliver high-quality audio output, providing a rich stereo sound experience. Moreover, the energy efficiency of the RDA5807M makes it suitable...

IR Clone is an open-source IR remote control analyzer tool. This utility can analyze any IR remote control that modulates the IR signal with a 38kHz carrier signal. This utility has an option to store and retrieve up to 16 IR signals. In addition, it has PC software to analyze and edit captured IR signals. The hardware component of this analyzer is built around the STM8S003F3 MCU. It has 24LC32 EEPROM installed to store the captured IR signals. This unit is designed to operate with a 5V to 9V DC power source or a 3V battery.  Finished prototype of the IR Clone module Operating modes such as capture or replay can be changed using an onboard jumper on the PCB. These operating modes can change at any time without restarting the unit. In addition to the IR clone PCB, the only external component needed to operate this system is a 4×4 matrix keypad . Most of the generally available 4×4 keypads can directly couple with this system. The dimensions of the IR Clone PCB are 41.2mm × 32.1m...

In this project, we built an STM8S005C6T6 based Ethernet development board for our IoT experiments. This development board consists of ENC28J60 , 10BASE-T stand-alone Ethernet controller, CH340G , USB serial interface, 2 LED indicators, and passive buzzer unit. The firmware framework for this development board has been developed using SDCC . To enable IPv4 support, we convert the EtherCard driver, which is available for the Arduino platform. The current version of this driver supports all other EtherCard functions except TCP support. Finished STM8S005C6T6 IoT development board. In the given design, the SPI terminals of the MCU are connected to the ENC28J60 Ethernet controller. All SPI terminals, such as MISO / PC7 , MOSI / PC6 , and SCK / PC5 , are connected directly to the Ethernet controller. In addition, the PC4 terminal of the MCU is used as ENC28J60, CHIP-SELECT .  The CH340G USB serial interface is connected to the UART2 terminals of the MCU. In STM8S005C6T6, the UAR...

This project is about an open source, USB based, 10 digit seven segment display unit. This unit is specifically designed to work with POS systems and banking applications. Initially, this system is developed to work with PC based systems, and later it was modified to work with other platforms and applications. Final view of the USB seven segment display module To simplify the communication interface this unit is designed to emulate a COM port in the host terminal. Because of this feature, this module can work with many systems without having any additional device driver(s). To extend the scope of this unit, it also comes with an option to switch between " direct mode " and " API mode ". In " direct mode " application or host device can directly send characters to the display unit over the emulated serial communication channel. The " API mode " is intended to provide more extensive features with this unit. All the " API mode ...

The main objective of this project is to design a maintenance free and low-cost light which automatically turns on and off at the predetermined time of the day. To meet the above requirement I designed this controller using ATmega8 MCU and DS1307 RTC. The driver stage of this light controller is intended to work with commonly available 7W LED modules. PCB of the programmable light controller. The core component of this programmable light is ATmega8 low power CMOS microcontroller. The main reason to select this microcontroller is it’s lower cost and higher availability. Except for the above two reasons this microcontroller also bundled with a rich set of peripherals which including 23 GPIOs, 3 independent timers, Two-wire serial interface, EEPROM, etc. Apart from ATmega8 microcontroller, this system uses DS1307 real time clock to maintain system time. Like ATmega8, DS1307 is also a very popular RTC in the market. This controller is designed to work with a 24V DC power supp...

AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on much audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quite difficult. The circuit described in this article is designed to replace AN6877 base LED drivers and it is based on commonly available components. This replacement LED driver is designed using 10, MMBT3904/2N3904 transistors and it can easily modify to get the necessary number of outputs. During the prototyping stages, we test this driver with a minimum of 7 LEDs (AN6877 configuration) and up to 12 LEDs. This LED driver is designed to work with 9V to 12V DC power source. With 7 LEDs and 9V power source, this module can directly replace AN6877 base LED driver modules. Schematic and PCB design related to this LED driver is available at google drive .

Electric Fences are designed to create an electrical circuit when touched by person (or animal). The circuits proposed in this article release 10kV electrical pulses to the fence-line and monitor the line status. This entire system is design to drive using 25V (5A) single-rail DC power source (using 5A power supply unit or pair of 12.6V Lead-Acid batteries). Main controller of this system is Microchip PIC12F675 – 8bit microcontroller. All the line monitoring, pulse generation and alarm system controlling is performed by this microcontroller. Some of the most notable features of this system are built-in audible alarm system, contactless fence line monitoring system, Support for wide range of step-up transformers (up to maximum of 10kV) and compact 10cm × 10cm PCB design. This system use standard electronic components (through-hole components) and SMD components in this provided PCB layout. All the project documents, schematics, PCB designs and firmware source codes are available...