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A simple interface circuit to drive VFD displays. No fancy parts required, and runs on serial communication.

What’s the Use?
VFD displays are not trending anymore for some obvious reasons, they are made of glass (“uh cool!”), have an incandescent filament (“really??”), they are basically vacuum tubes (“interesting!”), they make a light so brilliant, sometimes colored, it needs a dark plastic on top (“uh, cool again!”).

Usually you need a dedicated chip to drive em, most modules/appliances come with this chip that you can control independently via I2C or SPI (that is way better in terms of ease), in case you buy or have one of those displays and lack such chip it’s not so easy to “connect and go,” the ideal would be buying that chip (that comes in SMD format usually). This circuit gives a pretty decent interface for like an Arduino and can drive quite likely any VFD, including the bulky “tube” vintage ones, but matrix displays with a lot of segments are not a good idea by the way, you can expand the circuit but THOUSANDS… mhhh, maybe not.

Pros and Cons

- almost zero cost (hopefully)
- easy to find parts
- high voltage capability (up to hundreds Volts on the anodes)
- independent grids and anodes voltages
- only 3 digital data lines needed
- expandable (it requires more CPU work in case)
- code is ready made for every 8-bit Arduino

- requires a bunch of different voltages and supplies (not weird for VFDs)
- no dimming function (except from voltage drive)
- uses two Arduino resources, the SPI and timer1
- you can’t hang the microcontroller, otherwise the scan freezes on a grid
- it’s not a pair of resistors and Leds, it requires a bit of work”

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