I would like to present to the public the project of my watches on VLI. The IV-6 indicators are used to indicate the time, and the IV-1 is used for the dividing point. To obtain -40 volts DC and ~ 4 volts AC, a converter based on the KF1211EU1 microcircuit, power switches IRF7313 is used. The transformer has one primary winding with a midpoint, two secondary windings with a midpoint. In the primary winding 2 x 6 turns, in the secondary 2 x 50 turns and 2 x 4 turns, the material of the ferrite ring is N87, dimensions 10x6x4. To control the grids and segments of the indicators, the “bottom” BC857 keys in the SOT323 package are used. Real-time microcircuit - DS3231 in SO-16 package, microcontroller - Atmega328P in TQFP32 package. Installation is performed on two double-sided boards, boards are connected by a board-to-board connector. Also, under the indicators, an optional installation of SK6805 addressable LEDs is provided. The device operates on any 5 volt power supply unit that has a USB connector.For the firmware of the microcontroller, the corresponding contacts are displayed. You can use Atmega88, Atmega168, Atmega328, the firmware takes about 8kb without LED backlighting. The firmware is written in C (avr-gcc), the code is available on GitHubWhen ordering, you need to choose a thickness of 1mm or 1.2mm and a panel from pcbway. !!!The circuit uses a rare microcircuit KF1211EU1 (made in Russia)!!!
