This is a great project for a simple 7 segment clock. The Numitron tubes are cheap, easy to use and run directly from the 5V pin on the Raspberry Pi.
6 digit Numitron tube clock
- Six digit clock - hours / minute / seconds
- Time - uses NTP to stay very accurate
- Count down days, hours and minitues to a target date
- Display temperature in farenheit or celcius
- Scroll text across tubes
- Random scramble function to separate time / temp etc
74HC595 serial to parallel shift register ICs driven by a Raspberry Pi Zero This will work for any 7 segment clock with 74HC595 ICs
The Numitron IV-9 (AKA IV-9 / ИВ-9 / Reflector/ Sovtec Glühfaden Röhre) tubes are low voltage and run easily from the 5V rail on the Raspberry Pi (and Arduino for that matter)
Wiring the 74HC595 chips is easy and well documented on line. This is one of the better examples out there: https://www.arduino.cc/en/Tutorial/ShiftOut showing how to connect the 595s.
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Send fixes, questions or suggestions :)
Greg Lawler https://zinkwazi.com