Step 14: High Voltage Threading Throughout the Modules
Now that you have power supplied to the nixie tube driver modules, you should see all the elements in both nixie tube digits illuminated.
Use caution not to touch the high voltage output to the nixie tube driver modules. There is potentially enough energy here to cause a severe shock.
When nixie tube driver modules are connected edge-to-edge, left-to-right, both high voltage power and serial data from the external microcontroller are threaded through to all the boards.
A microcontroller is required to take full advantage of the nixie tube driver module shift register chain. The nixie tube driver module permits a microcontroller ( Arduino, etc.) to address two nixie tube digits, and via this shift register chain, multiple pairs of nixie tube digits.
For an example of how the nixie tube driver modules may be supported by an external microcontroller, see the sample Arduino digits driver code. Multiple nixie tube driver modules are seen operating together in the nixie tube driver module movie.
Depending how brightly you wish your nixie tubes to be illuminated, you can adjust VR1 to generate output between 170 and 250 volts DC. Increasing the output power will also allow you to drive more nixie tubes simultaneously.
Stay tuned for Part IV, where we'll hook up an Arduino Diecimila, and make some very long numbers. Extra special thanks to Nick de Smith.
See also this nice bit of work by Marc Pelletreau.