Nixie Clock/Aquarium type 22a

My type 22a design is a simple modification to my type 2a design that adds an output that can be turned on and off either manually or at specific times. In the first clock of this design, this output controls the swimming motion of fake magnetic fish in an aquarium, but it could just as easily control an alarm, switched outlet, or anything else.

Here's a crude mockup of what the clock actually looks like in operation.

Start clock simulation
JavaScript required, uses your computer's clock.

Push switch down Push switch up
These refer to a switch on the left rear of the clock. It is used for setting the clock and turning the fish on and off (neither of which is simulated here), but can also activate one of two alternate display modes.

Stop clock simulation
This will free up the memory and CPU time taken by the animation.

Normal display mode:
Display mode when switch pushed up (also turns on fish):
Display mode when switch pushed down (also turns off fish):
Display options:
Digit display time: / 120 of a second
Gap betwen digits: / 120 of a second
Fish start hour: 0-24, if set to 24 the fish never start swimming automatically (not simulated)
Fish stop hour: 0-24, if set to 24 the fish never stop swimming automatically (not simulated)
Fish start/stop minute: 0-59, applies to both start and stop times
Also not simulated here is the ability to set the time. This is done by pressing a button in a compartment in the lower back of the clock (where the aquarium's batteries used to go): each press selects the next settable value (hour, minute, month, day, century, year, and the nine option settings shown above), and the switch on the back raises or lowers the displayed value.

Click here for a copy of the instructions for setting the clock and filling it with water, in Acrobat PDF format.

Interior pictures of the clock, from top to bottom:

Top of the printed circuit board. The oddly-placed IC sockets into which the Nixies are plugged are there to correct a design flaw: originally the tubes were soldered directly to the board, straddling the two 74141 driver chips. However, I failed to take into account just how much refraction there would be in viewing the tubes through the hemispherical bowl of water: the right tube ended up not being visible at all! Shifting the tubes closer to the center gives a more reasonable viewing angle.
Bottom of circuit board. It's home made, single-sided, using the toner transfer method. It unfortunately needed a lot of jumper wires to connect the processor (a PIC16LF627A) to the driver chips.
Inside back of case, showing the mechanism that makes the fish "swim". It's a small DC motor, turning two permanent magnets via gear trains with very slightly different ratios.
The coral reef background has now been added. Parts of this were carved away to make room for the PCB and the wires going to it.
PCB installed, and all wires connected to it.

Contact

Any questions or comments about this page can be directed to: Jason Harper.

Normal display mode:
Display mode when switch pushed up (also turns on fish):
Display mode when switch pushed down (also turns off fish):
Display options:
Digit display time:	/ 120 of a second
Gap betwen digits:	/ 120 of a second
Fish start hour:	0-24, if set to 24 the fish never start swimming automatically (not simulated)
Fish stop hour:	0-24, if set to 24 the fish never stop swimming automatically (not simulated)
Fish start/stop minute:	0-59, applies to both start and stop times