Help - Wiring up six tubes

[mfmjos]

Thank you so much for creating the Arduinix kit.  I have bought, assembled and tested the kit.  Here is where I need a little help though.  I need help understanding how to wire up six tubes.  I have used the single tube schematic/wiring diagram and code to test the board and my tubes and it all works great.  But now I need some assistance in wiring up the additional tubes to create a functional clock.  Any help you can provide will be greatly appreciated.

Thanks!

[bcage]

I am probably the last one to be helping out since I am almost exactly in the same boat as you are... however, I have done something similar so I can try to help out.  First of all, if you are using the IN-17 tubes, you should probably get the pcb from robotpirate; that will basically wire the tubes for you.  If you don't have that tube, you will need to do something else.

First, you may have heard multiplexing mentioned for the Arduinix.  All that means is that not all tubes are lit simultaneously.  They are lit in sequence very quickly so that it appears that they are all lit at the same time.  The key to lighting the tube is the anode connection; think of it as the power and the cathode connections as the value (zero through nine).  To multiplex, the Arduino code will set the value for a tube and then turn on the anode for that tube to show the value.  Then it turns off the anode; changes the value to be what the next tube should be then turns on the anode for that tube... then it repeats for all the tubes.

You may have noticed, however, that the Arduinix has two sets of cathode connections (both zero to nine) and only 4 anode connections.  What the Arduinix does is use one anode to light two bulbs at a time with each set of cathodes providing the value for each of the two tubes.

This means that you will wire half of your tubes to one set of cathode pins on the Arduinix and the other half to the other set of cathode pins.  The anode connections will go across the two groups.

What this means is that you will need to wire half your tubes cathodes in parallel - this means make a connection from one of the cathode 0 pins to the "0" pins on half your tubes at the same time - think of a Y shaped connection from the Arduinix to each of the tubes or from the Arduinix to tube one then to tube two, etc... electrically these are the same.

Next wire the cathode 1 pin (from the same group of pins as the zero prior) to the "1" pins on those same tubes; 2 to 2; 3 to 3, etc... all the way to 9.  Call this group 1.

Repeat the same process for the other half of the tubes using the other set of cathode pins on the Arduinix.  Call this group 2.

Now, you will need to wire the anodes.  Note you have 4 anode pins on the Arduinix... since each lights two tubes at a time, this allows the Arduinix to drive a total of 8 tubes.  As described above, each anode will light two tubes.  You will wire from each anode pin on the Arduinix to two tubes; one from group 1 and one from group 2.  This last part is important or you will get tubes that are showing the same number since the cathodes in each group will provide a distinct value and the anode will light it up (so to speak).

What I don't know is the sequence of the tubes - e.g. anode 1, cathode group 1 is the high order hours digit (or the low order seconds digit), etc.  Each combination will correspond to a time data element - you may have to play with that and you can always adjust it in the Arduino code.

To summarize:

Each tube in group one has each of its cathodes connected to the group 1 pins on the Arduinix corresponding to the digit (0 to 0, etc)
Each tube in group two has each of its cathodes connected to the group 2 pins on the Arduinix corresponding to the digit (0 to 0, etc)
Each anode connects to a tube from group 1 and one from group 2

anode 1, cathode group 1 = something
anode 1, cathode group 2 = something else
anode 2, cathode group 1 = ...
through anode 4

Yes!  This is a lot of wires!  That is why the pcb route is much easier if you can find someone that has built one for your tubes.  I am using IN-18s... no such luck.  I do have some pcb sockets that will help a little, but I still anticipate a lot of wires and soldering... but, that is why I bought the kit instead of a finished clock!

If you don't know which pins on your tube correspond to each digit (they may not be sequential), you will need to google a "pinout" for your tube type.

I hope this helps.

Bill

[mfmjos]

Thanks for the reply.  What you describe is pretty much what I thought.  I did find some information on a website that helped (http://flockofbutterflies.blogspot.com/2009/11/arduinix-part-4-multiplexing.html).  I am not using IN-17 tubes so not prebuilt board for me.

Thanks for validating my suspicions.  I was hesitant to hook it up without a little more confirmation.  Maybe once I get it going I will put together a drawing and submit it here, for us noobs.

Here we go!

[Risen]

Bill -- That's a pretty good description of what's going on.

What I don't know is the sequence of the tubes - e.g. anode 1, cathode group 1 is the high order hours digit (or the low order seconds digit), etc.  Each combination will correspond to a time data element - you may have to play with that and you can always adjust it in the Arduino code.

There isn't a specific answer to that, because the ArduiNix doesn't have a predefined sequence. The sequence is created in the code.
For my clock, I chose:
A1 C0 - Hours high (tube 0)
A2 C0 - Hours low (1)
A3 C0 - Minutes high (2)
A1 C1 - Minutes low (3)
A2 C1 - Seconds high (4)
A3 C1 - Second low (5)
...which lights tubes 0+2, then 1+4, then 2+5, repeat.
But you can choose any sequence you can code.

I also built my own board and tube harness.
https://plus.google.com/u/0/photos/113825690086131396297/albums/5728271875401245617/5728271876241407938?pid=5728271876241407938&oid=113825690086131396297
https://plus.google.com/u/0/photos/113825690086131396297/albums/5728271875401245617/5865387316409291922?pid=5865387316409291922&oid=113825690086131396297
The harness photo didn't yet have the anode wires attached. I definitely recommend ribbon cable to keep the cables managed, but as you can see in the album I trashed the salvaged IDE (computer) cable I started with.

[bcage]

Very nice!  I checked out your images... any chance you might like to tell a DIY story about those?

[Risen]

Thanks!!

You can read the associated post.
https://plus.google.com/113825690086131396297/posts/3YxUHktmzoH