User Manual IN16-4-V1 Nixie Clock
Power for your Nixie Clock
The clock does not include a wall adapter. You should get a universal adapter yourself, these
are not very expensive. The preferred voltage is 12VDC, but often 9VDC – 15VDC will do
nicely too. The middle pin of the plug is the positive. Universal adapters often come with a set
of various plugs, choose one that fits. If none them fits, you can use the dc-plug is included
with the clock. If the clock does not work, you may have gotten the polarity wrong. Change
the polarity and try again.
Setting the Nixie Clock
Turn on the clock by plugging in the wall adapter. The time will start at 12:00 and blinks.
Press and hold the set button, for about 5-6 seconds until the first tube will turn on its decimal
point. Release the button.
Now, with each short press of the button, you can advance the first digit. The format is 24
hours, so the first tube only changes from 0-1-2 etcetera. After the digit is set correct, press
the button again for 2 seconds, and see that the second tube will turn on its decimal point. Set
all the other tubes in the same way.
Once you have set all digits, press and hold the button for 5-6 seconds, and the clock will
resume normal operation. Note that the internal timpekeeping of seconds will be reset to zero.
To set your clock as accurately as possible, press and hold the button exactly when your
reference clock changes to the next minute. The 5-6 seconds you need to hold don’t affect
this, the software compensates for that.
At first, this may seem a bit of a hassle, but after a while you will notice that it is remarkably
easy to set the clock.
Calibrating the Nixie Clock
The clock comes calibrated. There’s a label on the bottom with the correct calibration value
for use at normal room temperature. If you use the clock in extreme cold or warm places, you
may want to recalibrate it. Press and hold the set button, for about 7-8 seconds. While you
hold it, you will first see that the first tube turns on its decimal point, and then the second tube
will turn on its decimal point. Now release the button. There should be 4 digits displayed now.
Here you can set a new calibration value for the timing of the clock. First set this value at
5000. After setting this value, press and hold the button for 5-6 seconds, to return to normal
mode. This value will be stored inside the microcontroller. Turn off the clock, and turn it on
again.
Now set the clock, using a reliable time reference. Set the clock as described earlier, and wait
until your time reference matches the time you have set. Now press and hold the set button for
5-6 seconds, and notice that the clock now runs synchronous with your reference, both
displaying the same time.
Using the standard calibration value of 5000, the clock should run with a better accuracy than
+/- 10 seconds per day. Let the clock run for a couple of days, and note the time difference
