I wonder if the Arduino background program is causing the problem? It
does something to keep ocntrol of hte machine. Does anyone know what
that is? I don't.
The reason I ask is that you have no method of turning off the display
entirely. Your program changes one bit of the anode select at a time,
and one bit of the cathode select at a time. It is posible that the
clock spends some time displaying the wrong cathode or the wrong anode,
and this causes the ghost.
You could try to remove U1, the CD4028 anode decoder, and drive all six
anodes directly from the computer. That way, the code only changes one
bit to enable that digit's display.
Alternatively,you just have too much wire between the circuits and hte
tubes.
Please send a photo of the clock.
On 5/21/14 6:19 AM, Cristinello wrote:
Thank you very much for your proposals but unfortunately none of them
really work. I tried to modify my timings as Mr David suggested but it does
not get rid of the ghosting. I modified also the 100k resistor and that
does not really work either. Any other ideas? Thank you!
marți, 20 mai 2014, 19:01:22 UTC+3, threeneurons a scris:
Yes, alter your timing, as David suggested.
But also, those 100K resistors across the bases and emitters, of those
A92s can be made smaller. Say 10K. The junction, will keep the voltage
below 0.7V, so most of the current will still flow thru those junctions.
Those resistors' primary purpose is to bleed off charge once the voltage
drops below that 0.7V junction, and it starts looking like an open circuit.
Though, Its more likely a timing issue.
On Tuesday, May 20, 2014 5:43:16 AM UTC-7, Cristinello wrote:
Hello guys,
I built a relatively simple nixie clock and I am encountering severe
ghosting issues. To drive the mainboard I used an Arduino ( because I lack
programming knowledge) . I will attach the schematic and the .ino file from
the Arduino IDK . The schematic does not contain the nixie board beacuse it
is a modular design but it is straightforward. I am using 4028 BCD to
decimal decoder to drive the nixies and the transistors are SMD versions of
the FMMTA92 and 42. The power supply has also a strange behaviour , when
left without any consumer , the output voltage is going down wih aprox
1Volt/30 seconds. If someone has any idea about what may be wrong I will be
very very grateful .Thank you in advance!
--
David Forbes, Tucson AZ
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