hannah mishin

Portfolio and Blog of artist and technologist Hannah Mishin.  

Russian tri-color VFD Indicator Clock

This is an ongoing project.

I was drawn to the unique quality of this display.  I had just built a VFD 7 segment clock, and wanted to play around some more with Vacuum fluorescent displays.  

I am interested in making a clock - one which is not necessarily for telling THE time, but indicating the passing of time.


After doing the VFD clock, I found these Soviet new-old stock tri-color indicators on Ebay. 

The datasheet came in Russian, so I google translated the text.

I am going to use a MAX6921 20 output VFD driver chip.

https://datasheets.maximintegrated.com/en/ds/MAX6921-MAX6931.pdf

See this blog post about troubleshooting VFDs here: 

https://hannahmishin.com/blog/2015/7/18/vfd-display-clock

The above linked blog post explains a great deal of the logic of VFD displays.  That blog incorrectly drives the filaments and does not control for the multiplex rate properly. Part of the troubleshooting of this post will be in developing the hardware for the filament driver and properly controlling the code. 

This display has 3 colors: Blue, Red, and Green.  There are 5 lines with 7 of each color in each line - therefore, I have 35 Blue segments, 35 Red segments, and 35 Green segments. 

I have 21 addressable pins (7 of each color).


PINOUT.png

 

Current Glow: 225mA

Voltage Glow: 2.8v

Impulse current of elements of no more than mA     

        green glow: 7mA           

        red glow: 10mA           

        blue glow: 10mA

Impulse (pulsed) elements of voltage - the voltage of the elements pulsed     

        green glow:  25v           

        red, blue glow: 50v

Imupulse GRID current of no more than: 10mA

Impulse GRID voltage: 25v

 

Datasheet_draft1-pg2.png

HERE is a link to the direct translation of ILV2-5x7M


Beginning the wiring and coding.  I tested the transistor circuitry to control the grids with some LEDs.

The Russian VFD has five lines of segments of colors.  By switching the grids on and off I can multiplex the component.

Each Grid gets a circuit which is comprised of one TIP120 - (NPN), two 10K resistors, and an IRF9510 - (MOSFET PNP).


I am using a MAX6921AUI IC.