KiCAD circuit for a VFD Clock using the Popular ILV2-7/5 flat tube segmented nixie tube thingie
Not sure if this link still works
This work is greatly indebted to work that came before. Namely Callum Nunez-Vas and his Dogbone Watch which is also based on the cyberpunk wristwatch by johngineer.
I made some changes.
First, my uC is a PIC32MX250F128B, which supports USB OTG, which is nice and it's also Arduino compatible via ChipKIT and Digilent's DP32 which makes it nice for sharing.
The other thing that I changed is the oscillator that Callum used to drive the Cathode filament. Callum drives it with a timer on his PIC16F828. I needed more pins, so I decided to make a stand-alone relaxation oscillator built out of a 74HCG214 dual Schmidtt Trigger Inverter. I set mine up as a dual oscillator clocking at ~1KHz to drive the hours/mimutes Cathodes.
There's two pushbuttons for interfacing and an LED for control and user feedback. I'm using the same DS3231 that Callum uses, and also the MAX6920 for the high voltage SIPO to drive the segments.
It's pretty basic beyond that. The power supply is based on the Dogbone, but I'm using a 3V0 regulator instead of a 3V3 and I have a V-divider set up as a battery level sensor that the PIC can read.
- Maximum input Voltage 6V
- Minimum input Voltage 3.0V
- Current with VFD DISABLED ~26mA
- Current with VFD ENABLED showing all 8s ~150mA
Press Switch 2 once. The screen will print a lowercase b and then the voltage level with 0.01mV resolution. Press again to go back to time display.
Press Switch 1 once. Hour will blink. Press Switch 2 to increment hour.
Press Switch 1 again. Minute will blink. Press Switch 2 to increment minute.
Press Switch 1 again. Display will show option between 24 hour and 12 hour time. Press Switch 2 to toggle between 24h and 12h.
Press Switch 1 again to go back to the time display.
Switch 4 is the reset switch to the PIC. When you press it, the micro-contoller resets. It will start in 24 hour mode.
The thing runs on a high capacity LiPo battery. Plug it into a micro USB cable for charging. You can also program the PIC through the USB connection if you want to.