Step 1: How Magic Eye Tubes Work
Step 2: Where to Get Magic Eye Tubes
There are also other stores that stock these tubes, like Tubes Store or Nixie Kits that you can buy from.
Step 3: Kinds of Magic Eye Tubes
The one below is the 6E5, and the most common model. That's the tube I'll be using for the rest of this instructable.
Step 4: Using Magic Eye Tubes in Your Project
If you want to get one working with minimal effort, lots of Chinese sellers on ebay sell kits of prebuilt PCB drivers for these tubes. I got a couple, soldered them together, and had no problem with them.
Below you can see a schematic for a power supply for the tube. This will just turn it on, it won't control the shadow width.
Step 5: Controlling the Tube
Here's the datasheet for the 6E5 tube, which is what this schematic is for. Note that the schematic here has a solid line for the grid pin of the tube, and it's normally dotted (the grid pin is the one connected to R11). Here's what the letters mean in the pinout picture:
BS - Base Sleeve NC, x - No Connection
F - Filament P - Plate
G - Grid PB F - Beam Plates
H- Heater S - Shell
IC - Internal Connection K - Cathode
TA - Target
These are universal abbreviations, so if you see other tubes with these markings, that's what they mean.