Dilshan R Jayakody’s Web Log

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...

A few years back I purchased Honeywell CL15AE evaporative air cooler and it is15L indoor air cooler manufactured by JMATEK (for Honeywell). Sine last week this cooler became dead, and the only thing which I can see live is its red color power indicator. After disassembling the unit I see that most of the components of the controller PCB are rusted and damaged.  As I observed the main reason for corrosion is the absence of protective varnish on the top side of the PCB. The original control board of CL15AE cooler. At first, I restore all the damaged parts in the PCB with new parts, which including SS8050 , SS8550 , transistors and a few of electrolytic capacitors. After replacing those components, the unit starts to beep during power up but failed to power on. Damaged SS8050 and SS8550 transistors. After some tests, I figured out the problem is in SONiX SN8P2602 8-bit microcontroller.  Due to unavailability of microcontroller and it's firmware I decided to pr...