I just received and built up some ogi lumen display boards. These boards use Nixie tubes to display a numbers (0-9) with an old school/steampunk look. Each module consist of a display board with two Nixie digits and a driver board. The driver boards stack side by side with connectors that pass though all the necessary signals. This makes it easy to build as many display digits as you need, 2 digits at a time. To drive the displays you need a high voltage power supply (200 VDC)which is available from ogi lumen and a way to send serial data such as a microcontroller. The ogi lumen site includes sample code for the Arduino. I built up some boards so I have 2 modules (4 digits) and a high voltage supply. Everything went together without a problem. Read the full article for pictures and more details about ogi lumen kits.
The picture shown here is from a movie segment showing a very cool wave effect with the displays. Check out the video here.
Four Digits Running
I programmed my Freeduino board with the "drivermux" example program and wired it to the display. As you can see the left pair is brighter then right pair of digits but this shows up more in the photo then on the actual unit. I have not studied enough to know if there is an adjustment for this.
What is a Nixie Tube?
|Nixie Duo Kit
The Nixie Duo Kit includes two Nixie tubes which mount via sockets to a PCB which plugs into the driver board. The overall footprint of this setup is only slightly larger then the Nixie tubes and allows for them to be stacked side by side. The sockets are designed for soldering wires to the pins so large holes are used in the PCB to accommodate the soldering loops. You can dump a great deal of solder into these holes but it should not be necessary to fill them up. Just solder the loops to the pads and move on.
I found it very hard to plug in one of the Nixie tubes. I was afraid that solder had migrated up into the socket. A header pin was used to check each of the socket holes. The solder had not migrated as I feared. I just needed to wiggle the tube into the socket with a bit of force.
|Nixie Driver Kit
The driver kit was also very easy to put together. Just a few components to deal with. I did not use the large resistors pictured as I could tell from pictures at the ogi Lumen site that 1/4 watt resistors would work. I figured 1/4 Watt resistors would be easier to work with and I could save these higher wattage ones for other projects. I have plenty of resistors in bench stock so it was no problem to make the substitution.
Serial data is converted to 8 digital outputs by a 74595. These 8 bits are split into two 4-Bit controls, and sent to a 74141 The 74141 is a 1 of 10 driver chip designed to handle the high voltages needed by Nixie tubes. One 74141 for each digit.
To activate a filament for a digit, say the 2 digit, a binary 2 is loaded into the 4 bits for the desired digit. The 74141 decodes the binary 2 and activates its digit two output which sinks the high voltage supply across the Nixie number 2 filament causing it to light up.
The serial data is passed out through the stacking connector so you could stack several dual digits together to make a long number display such as the one in the wave video.
|Nixie Tube Power Supply
This is a high voltage supply for the Nixie tubes. The supply takes between 9 and 16 VDC and outputs 150 to 220 VDC at 50mA to drive up to 8 Nixie Duo boards (16 digits).
The power supp
|First Power Up
I had no faults with the assembly of my display driver or Nixie display boards. The instructions suggest that you power the display driver and displays without connecting your uC initially as a test. As you can see here, all the digits light at the same time.
I think the Nixie displays are very neat. I am hatching all kinds of project ideas. From a simple clock to a CPU load indicator that works with LCD Smartie. I did something similar with an analog meter in a previous article.
We are working with ogi lumen to bring you a comment contest. Like past contest here at uCHobby you will be able to win my making a comment with an application idea for the Nixie displays. The contest has not been finalized but it should not be long. If you comment on this article with an interesting idea we will include it in the contest when it happens.