The filament should be powered by AC. I used a 555 in 50% duty cycle configuration driving an H-bridge. If DC is used, there will be a brightness gradient because the filament is the cathode and its voltage differs from left to right.

Tom Kipgen is inspiration for unusual and gorgeous tube and crystal radio design, and he has two posted, each using one EM83 magic eye tube, the Green Tree and Winking Wedge sets.

http://www.kipgen.com/radios/sale/tubesets.htm

Apparently, they are both based on the first schematic by Jara “Krysatec” (“Rat”) on the following page.

http://www.schmarder.com/radios/visitors/jararat.htm

If anything I make ever looks half as good as Tom’s stuff, I’ll consider my life complete.

I wouldn’t know where to begin, but I’m more than ready to live vicariously through others when it comes to esoteric projects like that.

this itself is a very cool project!
major stuff from spritesmods

http://www.hpfriedrichs.com/rr-vfd.htm shows you how to use them as amplifier tubes, for instance – and pretty much anything that can amplify can also oscillate if you want it to – and occasionally when you don’t!

a nice new-year challenge would be to build a radio using vfds as the only active components – the internal construction of some will allow you to find two or more triodes in a single package once you figure the pinouts, so an am-only receiver for your local station with sufficient output for a small speaker or some walkman headphones shouldn’t be very difficult. ;-)