Nixie clock for a sleepyhead with New Year's Eve function

[Vermes]

Assumptions:

• the clock has to be exact
• remote-controlled
• alarm clock with snooze function
• you need to get up to turn the alarm off completely
• New Year's Eve function

Description of the system:
The clock consists of two boards: the display and the processor. They are connected by means of HEADERS allowing their separation if necessary. Nixie displays are Z573M. Lamp pins are connected by sliding into the bases, formed by filing the precision bases for integrated circuits. Each light is controlled through a separate system 74141. The board was painted with clear epoxy lacquer in spray. At the bottom board there are: power system, the inverter, the processor, IR receiver and real-time system with a generator.
Power system consists of six 220uF capacitors in two blocks (three capacitors each). The second block is powered by a 24ohm resistor to reduce the ripple and power destroyed on the stabilizer. The stabilizer is the 7805.
The converter is a typical layout on the transistor IRF740 with a coil 100uH. The transistor is the key PWM signal from the processor. Output voltage level is not controlled directly, and the compensation of the inverter load is implemented by a processor based on the data to display.
The processor is Atmega32 (16 is also okay). It sends BDC codes directly to 74141, receives commands from the IR receiver (TSOP36136/S) and controls the inverter. Countdown is executed by interrupt INT0 derived from RTC.
The RTC chip is PCF8583 clocked by DS32KHZ generator. According to the manufacturer's note, this generator may have a maximum deviation of 1s per week.

Housing
Wooden sides are made of board for meat. This is a solid beech wood, hard and good looking. The grooves for the pipe and boards were made with special tools. After grinding they were painted with lacquer. The programmer slot is milled from the bottom.

Program – features include:

• assign any R5 remote control
• set the date and time
• set the alarm
• snooze
• New Year's Eve function

The system PF8583 has a year record counting to four. This is needed to determine leap years. Counting the year must be addressed to the processor. It is achieved on a comparison at midnight the record read from the PCF system with content of the processor EEPROM. When they differ, the year is increased by one.
In the New Year's Eve, time is counted backwards, that means it tells how much time is left to theNew Year. The clock operates normally, and the value to display is converted (m=59-m, h=23-h, s=59-s). This means that if we set the alarm clock for 8:00a.m., we wake up at 4:00p.m. to New Year. The algorithm is not perfect and shifts of time (2s) normal to the countdown.



Link to original thread (video and attachment: PCB + program)– Zegar Nixie dla śpiocha z funkcją sylwestrową.