This is one of three PCB’s I require for this project. It is the most important PCB because it drives my nixie tubes. it does so in a relatively simple way.
On the PCB there are 60 MOSFETs, one for each of the cathodes of the nixie tubes.
The MOSFETs have complementary pull-down resistors and inrush current-limiting resistors.
The MOSFETs are driven by 4 16-bit I/O expanders that are controlled via the I2C-bus.
Also present on the board are 6 opto-couplers, these are used to dim the nixie tubes. The optocouplers are connected to the 180V-rail and to the anode-resistors of the nixie tubes.
There is a PWM IC on the board that drives the optocouplers and also drives 4 MOSFETs that are used to control little nixie tubes that are used as colon-separators. This IC is also controlled via the I2C-bus.
Finally, there are 6 WS1812b addressable RGB-LED’s on the board. These are used to provide a subtle underglow under the nixie tubes. They are controlled via a 1-wire interface.
All the interfaces (SDA, SCL, 1W, 5V, GND) are connected to a 5 pin-header. The 180V-rail and GND are connected to a 2-pole screw terminal.
I also had another PCB produced. This PCB has 3 copper pads and some u.FL connector pads. It will be used as an input board to connect to capacitive touch circuits.