Re: [neonixie-l] IV-11

[Yuriy Ovchinnikov]

$5.3 and free shipping.

пт, 26 мар. 2021 г. в 10:26, Michail Wilson :

> Better price to buy all?
>
>
>
> Michail Wilson
>
> 206-920-6312
>
>
>
> *From:* neonixie-l@googlegroups.com  *On
> Behalf Of * ??
> *Sent:* Friday, March 26, 2021 12:17 AM
> *To:* neonixie-l 
> *Subject:* [neonixie-l] IV-11
>
>
>
> Hi,
>
> I can find 500 pcs. IV-11 for $5,5 ea. Does anyone need them?
>
> --
> You received this message because you are subscribed to the Google Groups
> "neonixie-l" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to neonixie-l+unsubscr...@googlegroups.com.
> To view this discussion on the web, visit
> https://groups.google.com/d/msgid/neonixie-l/eac867e3-5673-4b08-ae03-6ee1191cf780n%40googlegroups.com
> 
> .
>
> --
> You received this message because you are subscribed to the Google Groups
> "neonixie-l" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to neonixie-l+unsubscr...@googlegroups.com.
> To view this discussion on the web, visit
> https://groups.google.com/d/msgid/neonixie-l/MW2PR0102MB343556D058B3B5E7CCF5A89382619%40MW2PR0102MB3435.prod.exchangelabs.com
> 
> .
>

-- 
You received this message because you are subscribed to the Google Groups 
"neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/CAFbEjqijwuD2gSfqcVyBnAgwGjiu7sN-cSVqZMVJt%3DbtYgUC7g%40mail.gmail.com.

RE: [neonixie-l] IV-11

[Michail Wilson]

Better price to buy all?

Michail Wilson
206-920-6312

From: neonixie-l@googlegroups.com  On Behalf Of 
 ??
Sent: Friday, March 26, 2021 12:17 AM
To: neonixie-l 
Subject: [neonixie-l] IV-11

Hi,
I can find 500 pcs. IV-11 for $5,5 ea. Does anyone need them?
--
You received this message because you are subscribed to the Google Groups 
"neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to 
neonixie-l+unsubscr...@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/eac867e3-5673-4b08-ae03-6ee1191cf780n%40googlegroups.com.

-- 
You received this message because you are subscribed to the Google Groups 
"neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/MW2PR0102MB343556D058B3B5E7CCF5A89382619%40MW2PR0102MB3435.prod.exchangelabs.com.

Re: [neonixie-l] IV-11 VFD clock, some questions

[GastonP]

Actually, brightness is a needed feature when this displays are used as 
intended. They were designed and are still used with heavy optical filters 
in front, to enhance contrast and visually eliminate the tube mechanical 
internal structure from the users view.
We of course like to see the tube naked, but we have to live with the cost 
of the features :)

Gastón

On Tuesday, November 19, 2013 7:01:33 PM UTC-3, Adam Jacobs wrote:


I think that one of the features of Vacuum Fluorescent Display is 
 brightness. To paraphrase someone wiser than me: If you find yourself 
 thinking up more and more convoluted mechanisms for making it work, then 
 that's often an indicator that you're barking up the wrong tree. 

 -Adam 

 On 11/19/2013 12:48 PM, David Forbes wrote: 
  
  
  Also, if your VFD is too bright, you can reduce the brightness by 
  reducing the duty cycle, which is done by turning off the anodes on 
  for some time in each cycle. 
  



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/27d28f9e-d3d9-40d8-841c-674f673e1bd9%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

I know the difference between a nixie and a VFD tube but I have to say that 
your explanation is very nice to summarize all the loose bits of 
information in my head. 

So If I have a 6 volt supply for my four filaments (in series) I would not 
need a resistor. I think the 7806 won't get that warm with roughly 400ma 
going through it but I can always take a simple switching psu for it or 
attach it to my (metal) enclosure. I will simply use a DC filament supply 
then to keep things simple (this project is going to be complicated 
enough). 

My only remaining concern is the driving method, I would like to order all 
my parts off ebay and/or tayda electronics. Places like mouser etc have (in 
my opinion) ridiculous shipping rates so I would like to avoid them. 
Another point is that the max6921 costs around 6-7 dollar a piece +1 euro 
for a plcc socket, I am trying to keep the costs down a bit. So a method to 
avoid using these drivers is preferred. 

HV5812: cheap but shipping costs are 40-50 dollar
MAX6921 expensive and/or high shipping costs


Op dinsdag 19 november 2013 20:06:50 UTC+1 schreef Adam Jacobs:

  Hi Gideon,

 I think that you have some confusion regarding how VFDs are driven. VFDs 
 are not nixie tubes or anything even similar. Nixies are not vacuum tubes, 
 they are cold-cathode (neon) tubes. With nixies, we place ~180vdc across 
 the anode  cathode via a current-limiting resistor. The reason for 
 current-limiting in a nixie is because as current increases, nixie 
 impedance decreases, causing the neon tube to rapidly begin dissipating a 
 catastrophic amount of heat. Nixies, being neons, regulate voltage to their 
 maintenance voltage. Any reasonable voltage above the striking voltage will 
 work fine.

 VFDs are triodes: Hot-cathode vacuum tubes. Ideally, the filament is 
 driven with an AC supply of the designed voltage (via the two filament 
 pins, usually a couple of volts) and the anode segments are driven with a 
 voltage regulated DC supply at the designed voltage (usually 20-30v for 
 direct and ~60v for multiplex). The grid is driven exactly the same as an 
 anode segment and is used to turn the display 'on'. There are no 
 current-limiting resistors used for driving the anode segments or the grid!

 In my VFD clocks, I used the trick (which I learned from here) of driving 
 the filaments with DC. This works fine if you are using individual numeral 
 VFD tubes, I wouldn't try it if you are using the big multi-numeral VFD 
 display tubes. The (known) current draw of the filament is used for 
 calculating a resistor-divider. One leg of the filament is tied to ground, 
 the other leg to +5vdc via the resistor. If you go with this approach be 
 sure to do your math on the front end. These filaments draw a lot of 
 current, which means a lot of heat dissipation in the voltage-divider 
 resistor. Driving this setup via a linear regulator supply would need a 
 very large heat-sink. I would recommend using a switching supply like the 
 LM2575. Obviously, if you have an AC supply that is the correct voltage for 
 the filament then no resistor is needed.
 For a schematic: http://elbastl.sweb.cz/6-digit-VFD.zip

 I liked Maxim IC's 6921 driver IC. I know you specifically called it out 
 as not an option, but it worked well for me. Specifically, I used the PLCC 
 package because I work exclusively in protoboard and there are easy DIP 
 PLCC sockets. There are numerous advantages in my opinion to the dedicated 
 VFD driver chip. Instead of 8 dedicated GPIO pins (7-segments + grid), the 
 6921 uses a standard SPI interface. This would be even more advantageous on 
 16-segment VFDs.

 One thing you mentioned: Yes, 60v applied to the anodes will be VERY 
 bright, even if multiplexed. I had to move my VFD clocks to bright places 
 like my desk at work. a LOT brighter than equivalent nixie designs. I spent 
 some time dialing back the supply voltages before finally giving up and 
 accepting that VFDs are just designed to be bright.

 -Adam

   

 On 11/19/2013 5:09 AM, Gideon Wackers wrote:
  
 I want to build a four digit VFD clock (three of them actually) without 
 using drivers like the max6921. I have two possibilities at this moment, 
 one is this http://i.imgur.com/D4FGaV1.jpg and the other being this one 
 http://i.imgur.com/5fMc7ty.png . Which would be best? 

  Another question is the resistor that I will need:
 0.0035/25*3 = 0.00042
 60/0.00042 = 140k = 130K or 150K ohm  for R1   and 100k for R2
  
  For the grids the same circuit applies but with a slightly different 
 value for R1 due to the different current. 
 But this implies that I use 60 volt. A few people said that the tubes are 
 very bright at the recommended 50-70 volt for multiplexed tubes so if I 
 lower the voltage to 40 volts I would suddenly need only 100K for R1. Will 
 I bump into problems if I lower the voltage to lets say 40 volts but when 
 my resistors are calculated for 60 volt?

  I want to make the filament 

Re: [neonixie-l] IV-11 VFD clock, some questions

[John Rehwinkel]

 So now I only have to figure out wether my two transistor driver is a good 
 way to drive my IV-11 tubes :)

I was hoping someone more versed in the intricacies of transistors would 
address this, but they haven't, so I'll take a stab at it.

 I want to build a four digit VFD clock (three of them actually) without using 
 drivers like the max6921. I have two possibilities at this moment, one is 
 this http://i.imgur.com/D4FGaV1.jpg

This one has Q1 in a common base configuration, which does not provide 
current gain.  It seems to me like it would put Q1 into its linear region (due 
to the drop across R1), so you might have to fiddle with the R values to get Q2 
to turn on and off reliably.  Since you're dealing with low currents, it should 
work fine.

 and the other being this one http://i.imgur.com/5fMc7ty.png .

This is a more traditional common emitter configuration, where both 
transistors can give current gain.  Instead of the usual series base resistor 
to limit current, there's an emitter resistor which does double duty of 
limiting both the base and collector currents.

 Which would be best?

I'd slightly prefer the second over the first (although there are reasons you 
might want to use the first one, involving current limiting and the like).

They both work essentially the same way: the PNP transistor is kept turned off 
by its base bias resistor to V+, until the NPN transistor turns on, and pulls 
the base down toward ground, thereby turning on the PNP transistor, which then 
provides V+ out of its collector to drive the VFD anodes/grids.  The NPN 
transistor's emitter resistor limits the current flowing through both 
transistors (it does not control the amount of current available to the VFD, 
except in a sort of indirect fashion - normally the transistors are fully off 
or fully on).

 Another question is the resistor that I will need:
 0.0035/25*3 = 0.00042
 60/0.00042 = 140k = 130K or 150K ohm  for R1   and 100k for R2
 
 For the grids the same circuit applies but with a slightly different value 
 for R1 due to the different current.

As I said, those resistors don't really control the current into the VFD.  
However, the VFD doesn't need to be current limited, so all the resistors do is 
protect the transistors and microcontroller.

 But this implies that I use 60 volt. A few people said that the tubes are 
 very bright at the recommended 50-70 volt for multiplexed tubes so if I lower 
 the voltage to 40 volts I would suddenly need only 100K for R1. Will I bump 
 into problems if I lower the voltage to lets say 40 volts but when my 
 resistors are calculated for 60 volt?

Again, the resistors are only there for current limiting, and they're not 
terribly critical.  If the transistors turn on and off reliably, and there 
isn't too much current through them, you're fine.

- John

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/503D6874-D978-43FF-9203-45EBB30472AA%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

Thank you very much for this reply, I'll just order a few values and see 
what works. 

But I am missing one thing to complete the story; why are current values 
given in the datasheet if there is no need for current regulation? or 
should those be seen as normal values that you will see during operation 
just as with the filament current. 

Op dinsdag 19 november 2013 21:36:56 UTC+1 schreef jrehwin:

  So now I only have to figure out wether my two transistor driver is a 
 good way to drive my IV-11 tubes :) 

 I was hoping someone more versed in the intricacies of transistors would 
 address this, but they haven't, so I'll take a stab at it. 

  I want to build a four digit VFD clock (three of them actually) without 
 using drivers like the max6921. I have two possibilities at this moment, 
 one is this http://i.imgur.com/D4FGaV1.jpg 

 This one has Q1 in a common base configuration, which does not provide 
 current gain.  It seems to me like it would put Q1 into its linear region 
 (due to the drop across R1), so you might have to fiddle with the R values 
 to get Q2 to turn on and off reliably.  Since you're dealing with low 
 currents, it should work fine. 

  and the other being this one http://i.imgur.com/5fMc7ty.png . 

 This is a more traditional common emitter configuration, where both 
 transistors can give current gain.  Instead of the usual series base 
 resistor to limit current, there's an emitter resistor which does double 
 duty of limiting both the base and collector currents. 

  Which would be best? 

 I'd slightly prefer the second over the first (although there are reasons 
 you might want to use the first one, involving current limiting and the 
 like). 

 They both work essentially the same way: the PNP transistor is kept turned 
 off by its base bias resistor to V+, until the NPN transistor turns on, and 
 pulls the base down toward ground, thereby turning on the PNP transistor, 
 which then provides V+ out of its collector to drive the VFD anodes/grids. 
  The NPN transistor's emitter resistor limits the current flowing through 
 both transistors (it does not control the amount of current available to 
 the VFD, except in a sort of indirect fashion - normally the transistors 
 are fully off or fully on). 

  Another question is the resistor that I will need: 
  0.0035/25*3 = 0.00042 
  60/0.00042 = 140k = 130K or 150K ohm  for R1   and 100k for R2 
  
  For the grids the same circuit applies but with a slightly different 
 value for R1 due to the different current. 

 As I said, those resistors don't really control the current into the VFD. 
  However, the VFD doesn't need to be current limited, so all the resistors 
 do is protect the transistors and microcontroller. 

  But this implies that I use 60 volt. A few people said that the tubes 
 are very bright at the recommended 50-70 volt for multiplexed tubes so if I 
 lower the voltage to 40 volts I would suddenly need only 100K for R1. Will 
 I bump into problems if I lower the voltage to lets say 40 volts but when 
 my resistors are calculated for 60 volt? 

 Again, the resistors are only there for current limiting, and they're not 
 terribly critical.  If the transistors turn on and off reliably, and there 
 isn't too much current through them, you're fine. 

 - John 



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/0ba935a7-397b-4a2e-88e6-10f67704d633%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[David Forbes]

On 11/19/2013 1:36 PM, John Rehwinkel wrote:

I want to build a four digit VFD clock (three of them actually) without using 
drivers like the max6921. I have two possibilities at this moment, one is this 
http://i.imgur.com/D4FGaV1.jpg
and the other being this one http://i.imgur.com/5fMc7ty.png .
Which would be best?




I'd use the more traditional design with a resistor in series with the base of 
the NPN transistor driven by the CPU, rather than the emitter resistor as you 
showed.


More or less like this:
http://www.dos4ever.com/nixie1/multiplexing.gif

That resistor R5 from base to emitter of the PNP transistor can be a lot lower 
value, as low as R6/Vanode. It will make the anode turn off faster, the lower 
resistance it is.


The transistors can be any type rated for more than the VFD anode supply.

Also, if your VFD is too bright, you can reduce the brightness by reducing the 
duty cycle, which is done by turning off the anodes on for some time in each cycle.


--
David Forbes, Tucson, AZ

--
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/528BCE92.509%40dakotacom.net.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[John Rehwinkel]

 I'd use the more traditional design with a resistor in series with the base 
 of the NPN transistor driven by the CPU, rather than the emitter resistor as 
 you showed.

David has a point - the disadvantage is it uses one more resistor, the (large) 
advantage is the functions are now separated - R7 limits the current out of the 
microcontroller pin into the base of T2, and R6 limits the current through T2 
into the base of T1.  Since they're separate, they can be different values (as, 
in fact, they are).  You might have to tweak R6 a bit lower, since the supply 
voltage will be less for VFD use (R7 is fine).

- John

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/71D973B2-2B82-4568-BC33-FE5331DAF359%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

http://i.imgur.com/CFTb8gI.png

is this what you mean?

Eagle was being weird today so I had to draw it in lochmaster

Why is that better than the original two ideas? I would like to understand 
everything :)

Op dinsdag 19 november 2013 21:48:18 UTC+1 schreef nixiebunny:

 On 11/19/2013 1:36 PM, John Rehwinkel wrote: 
  I want to build a four digit VFD clock (three of them actually) without 
 using drivers like the max6921. I have two possibilities at this moment, 
 one is this http://i.imgur.com/D4FGaV1.jpg 
  and the other being this one http://i.imgur.com/5fMc7ty.png . 
  Which would be best? 
  

 I'd use the more traditional design with a resistor in series with the 
 base of 
 the NPN transistor driven by the CPU, rather than the emitter resistor as 
 you 
 showed. 

 More or less like this: 
 http://www.dos4ever.com/nixie1/multiplexing.gif 

 That resistor R5 from base to emitter of the PNP transistor can be a lot 
 lower 
 value, as low as R6/Vanode. It will make the anode turn off faster, the 
 lower 
 resistance it is. 

 The transistors can be any type rated for more than the VFD anode supply. 

 Also, if your VFD is too bright, you can reduce the brightness by reducing 
 the 
 duty cycle, which is done by turning off the anodes on for some time in 
 each cycle. 

 -- 
 David Forbes, Tucson, AZ 


-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/605f3a58-2171-4e25-8437-89bde256c741%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

I was typing the previous reply while you posted it, that clears some 
things up. 

You mention tweaking the value, is there a way to actually calculate it? 
(I'm not that much into transistor calculations as you may have noticed)

Op dinsdag 19 november 2013 22:06:16 UTC+1 schreef jrehwin:

  I'd use the more traditional design with a resistor in series with the 
 base of the NPN transistor driven by the CPU, rather than the emitter 
 resistor as you showed. 

 David has a point - the disadvantage is it uses one more resistor, the 
 (large) advantage is the functions are now separated - R7 limits the 
 current out of the microcontroller pin into the base of T2, and R6 limits 
 the current through T2 into the base of T1.  Since they're separate, they 
 can be different values (as, in fact, they are).  You might have to tweak 
 R6 a bit lower, since the supply voltage will be less for VFD use (R7 is 
 fine). 

 - John 



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/22dc8faf-3472-4492-ab68-6fddc738a31d%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Adam Jacobs]

FYI David:
  On the clock that I built with IV-11 tubes, I initially started with 
an anode voltage of 60v; which is the median multiplexed voltage as per 
this datasheet: http://www.tromop.eu/cms/media/IV-11%20datasheet.pdf and 
a 1/6 duty cycle (16.67%). That clock was bright. Couldn't sleep in the 
room with it running, way too bright. I tried lowering the anode voltage 
supply to 50v, which is the minimum voltage listed in the datasheet for 
multiplexed mode. This helped, but not enough; not by a long shot.
  So, then I started lowering duty cycle. I can't remember how low I 
eventually took it, but I soon realized that I wouldn't be able to get 
the brightness as low as I needed without introducing some very 
noticeable flicker. So, I moved the voltage back to 60v and the duty 
cycle back to 1/6 and moved the clock to a much brighter location. Works 
perfect. :) FYI, this was with the filament @ 1.5vdc. I don't know 
enough about VFDs to know if lowering the filament voltage might have 
helped.
  I think that one of the features of Vacuum Fluorescent Display is 
brightness. To paraphrase someone wiser than me: If you find yourself 
thinking up more and more convoluted mechanisms for making it work, then 
that's often an indicator that you're barking up the wrong tree.


-Adam

On 11/19/2013 12:48 PM, David Forbes wrote:



Also, if your VFD is too bright, you can reduce the brightness by 
reducing the duty cycle, which is done by turning off the anodes on 
for some time in each cycle.




--
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/528BDFBD.2080509%40gmail.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Adam Jacobs]

Hi Gideon,
  How many of these clocks are you planning to build? If it is just a 
few, then I wouldn't sweat the costs too much. Both of those companies 
(used to be - I assume still) are very generous with samples. I agree 
that the Supertex and Maxim parts can be difficult to obtain for a low 
price in individual quantities from normal vendors. I've got a drawer 
full of Supertex and Maxim samples, I'd be happy to mail you the parts. 
FYI, requests for samples get a much more positive response if you use a 
company or university email and describe a plausible project in the 
request. Any time that I can't find some obscure part that is listed for 
a project, I move to the obscure part manufacturer's website and request 
a sample. No problem.


Contact me off-list with your address  parts request and I'll see what 
I can do. Of course, if you're designing a clock for mass production, 
then all bets are off. :)


-Adam

On 11/19/2013 11:39 AM, Gideon Wackers wrote:
I know the difference between a nixie and a VFD tube but I have to say 
that your explanation is very nice to summarize all the loose bits of 
information in my head.


So If I have a 6 volt supply for my four filaments (in series) I would 
not need a resistor. I think the 7806 won't get that warm with roughly 
400ma going through it but I can always take a simple switching psu 
for it or attach it to my (metal) enclosure. I will simply use a DC 
filament supply then to keep things simple (this project is going to 
be complicated enough).


My only remaining concern is the driving method, I would like to order 
all my parts off ebay and/or tayda electronics. Places like mouser etc 
have (in my opinion) ridiculous shipping rates so I would like to 
avoid them. Another point is that the max6921 costs around 6-7 dollar 
a piece +1 euro for a plcc socket, I am trying to keep the costs down 
a bit. So a method to avoid using these drivers is preferred.


HV5812: cheap but shipping costs are 40-50 dollar
MAX6921 expensive and/or high shipping costs


Op dinsdag 19 november 2013 20:06:50 UTC+1 schreef Adam Jacobs:

Hi Gideon,

I think that you have some confusion regarding how VFDs are
driven. VFDs are not nixie tubes or anything even similar. Nixies
are not vacuum tubes, they are cold-cathode (neon) tubes. With
nixies, we place ~180vdc across the anode  cathode via a
current-limiting resistor. The reason for current-limiting in a
nixie is because as current increases, nixie impedance decreases,
causing the neon tube to rapidly begin dissipating a catastrophic
amount of heat. Nixies, being neons, regulate voltage to their
maintenance voltage. Any reasonable voltage above the striking
voltage will work fine.

VFDs are triodes: Hot-cathode vacuum tubes. Ideally, the filament
is driven with an AC supply of the designed voltage (via the two
filament pins, usually a couple of volts) and the anode segments
are driven with a voltage regulated DC supply at the designed
voltage (usually 20-30v for direct and ~60v for multiplex). The
grid is driven exactly the same as an anode segment and is used to
turn the display 'on'. There are no current-limiting resistors
used for driving the anode segments or the grid!

In my VFD clocks, I used the trick (which I learned from here) of
driving the filaments with DC. This works fine if you are using
individual numeral VFD tubes, I wouldn't try it if you are using
the big multi-numeral VFD display tubes. The (known) current draw
of the filament is used for calculating a resistor-divider. One
leg of the filament is tied to ground, the other leg to +5vdc via
the resistor. If you go with this approach be sure to do your math
on the front end. These filaments draw a lot of current, which
means a lot of heat dissipation in the voltage-divider resistor.
Driving this setup via a linear regulator supply would need a very
large heat-sink. I would recommend using a switching supply like
the LM2575. Obviously, if you have an AC supply that is the
correct voltage for the filament then no resistor is needed.
For a schematic: http://elbastl.sweb.cz/6-digit-VFD.zip
http://elbastl.sweb.cz/6-digit-VFD.zip

I liked Maxim IC's 6921 driver IC. I know you specifically called
it out as not an option, but it worked well for me. Specifically,
I used the PLCC package because I work exclusively in protoboard
and there are easy DIP PLCC sockets. There are numerous advantages
in my opinion to the dedicated VFD driver chip. Instead of 8
dedicated GPIO pins (7-segments + grid), the 6921 uses a standard
SPI interface. This would be even more advantageous on 16-segment
VFDs.

One thing you mentioned: Yes, 60v applied to the anodes will be
VERY bright, even if multiplexed. I had to move my VFD clocks to
bright places like my desk at work. a LOT brighter than equivalent
nixie 

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

I'm going to make three clocks (Christmas presents for girlfriend, brother 
and sister), but I'll see if I can get samples approved with my university 
email. Thank you for your generous offer to send me some samples but I'll 
first try to get my own samples at a reasonable price. 


Op dinsdag 19 november 2013 23:09:11 UTC+1 schreef Adam Jacobs:

  Hi Gideon,
   How many of these clocks are you planning to build? If it is just a few, 
 then I wouldn't sweat the costs too much. Both of those companies (used to 
 be - I assume still) are very generous with samples. I agree that the 
 Supertex and Maxim parts can be difficult to obtain for a low price in 
 individual quantities from normal vendors. I've got a drawer full of 
 Supertex and Maxim samples, I'd be happy to mail you the parts. FYI, 
 requests for samples get a much more positive response if you use a company 
 or university email and describe a plausible project in the request. Any 
 time that I can't find some obscure part that is listed for a project, I 
 move to the obscure part manufacturer's website and request a sample. No 
 problem.

 Contact me off-list with your address  parts request and I'll see what I 
 can do. Of course, if you're designing a clock for mass production, then 
 all bets are off. :)

 -Adam

 On 11/19/2013 11:39 AM, Gideon Wackers wrote:
  
 I know the difference between a nixie and a VFD tube but I have to say 
 that your explanation is very nice to summarize all the loose bits of 
 information in my head.  

  So If I have a 6 volt supply for my four filaments (in series) I would 
 not need a resistor. I think the 7806 won't get that warm with roughly 
 400ma going through it but I can always take a simple switching psu for it 
 or attach it to my (metal) enclosure. I will simply use a DC filament 
 supply then to keep things simple (this project is going to be complicated 
 enough). 

  My only remaining concern is the driving method, I would like to order 
 all my parts off ebay and/or tayda electronics. Places like mouser etc have 
 (in my opinion) ridiculous shipping rates so I would like to avoid them. 
 Another point is that the max6921 costs around 6-7 dollar a piece +1 euro 
 for a plcc socket, I am trying to keep the costs down a bit. So a method to 
 avoid using these drivers is preferred. 

  HV5812: cheap but shipping costs are 40-50 dollar
 MAX6921 expensive and/or high shipping costs


 Op dinsdag 19 november 2013 20:06:50 UTC+1 schreef Adam Jacobs: 

  Hi Gideon,

 I think that you have some confusion regarding how VFDs are driven. VFDs 
 are not nixie tubes or anything even similar. Nixies are not vacuum tubes, 
 they are cold-cathode (neon) tubes. With nixies, we place ~180vdc across 
 the anode  cathode via a current-limiting resistor. The reason for 
 current-limiting in a nixie is because as current increases, nixie 
 impedance decreases, causing the neon tube to rapidly begin dissipating a 
 catastrophic amount of heat. Nixies, being neons, regulate voltage to their 
 maintenance voltage. Any reasonable voltage above the striking voltage will 
 work fine.

 VFDs are triodes: Hot-cathode vacuum tubes. Ideally, the filament is 
 driven with an AC supply of the designed voltage (via the two filament 
 pins, usually a couple of volts) and the anode segments are driven with a 
 voltage regulated DC supply at the designed voltage (usually 20-30v for 
 direct and ~60v for multiplex). The grid is driven exactly the same as an 
 anode segment and is used to turn the display 'on'. There are no 
 current-limiting resistors used for driving the anode segments or the grid!

 In my VFD clocks, I used the trick (which I learned from here) of driving 
 the filaments with DC. This works fine if you are using individual numeral 
 VFD tubes, I wouldn't try it if you are using the big multi-numeral VFD 
 display tubes. The (known) current draw of the filament is used for 
 calculating a resistor-divider. One leg of the filament is tied to ground, 
 the other leg to +5vdc via the resistor. If you go with this approach be 
 sure to do your math on the front end. These filaments draw a lot of 
 current, which means a lot of heat dissipation in the voltage-divider 
 resistor. Driving this setup via a linear regulator supply would need a 
 very large heat-sink. I would recommend using a switching supply like the 
 LM2575. Obviously, if you have an AC supply that is the correct voltage for 
 the filament then no resistor is needed.
 For a schematic: http://elbastl.sweb.cz/6-digit-VFD.zip

 I liked Maxim IC's 6921 driver IC. I know you specifically called it out 
 as not an option, but it worked well for me. Specifically, I used the PLCC 
 package because I work exclusively in protoboard and there are easy DIP 
 PLCC sockets. There are numerous advantages in my opinion to the dedicated 
 VFD driver chip. Instead of 8 dedicated GPIO pins (7-segments + grid), the 
 6921 uses a standard SPI interface. This would be even more 

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

Does anyone know whether it is a bad idea to go below the recommended 
multiplexing voltage as mentioned in Adams comment??

Op dinsdag 19 november 2013 23:01:33 UTC+1 schreef Adam Jacobs:

 FYI David: 
On the clock that I built with IV-11 tubes, I initially started with 
 an anode voltage of 60v; which is the median multiplexed voltage as per 
 this datasheet: http://www.tromop.eu/cms/media/IV-11%20datasheet.pdf and 
 a 1/6 duty cycle (16.67%). That clock was bright. Couldn't sleep in the 
 room with it running, way too bright. I tried lowering the anode voltage 
 supply to 50v, which is the minimum voltage listed in the datasheet for 
 multiplexed mode. This helped, but not enough; not by a long shot. 
So, then I started lowering duty cycle. I can't remember how low I 
 eventually took it, but I soon realized that I wouldn't be able to get 
 the brightness as low as I needed without introducing some very 
 noticeable flicker. So, I moved the voltage back to 60v and the duty 
 cycle back to 1/6 and moved the clock to a much brighter location. Works 
 perfect. :) FYI, this was with the filament @ 1.5vdc. I don't know 
 enough about VFDs to know if lowering the filament voltage might have 
 helped. 
I think that one of the features of Vacuum Fluorescent Display is 
 brightness. To paraphrase someone wiser than me: If you find yourself 
 thinking up more and more convoluted mechanisms for making it work, then 
 that's often an indicator that you're barking up the wrong tree. 

 -Adam 

 On 11/19/2013 12:48 PM, David Forbes wrote: 
  
  
  Also, if your VFD is too bright, you can reduce the brightness by 
  reducing the duty cycle, which is done by turning off the anodes on 
  for some time in each cycle. 
  



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/b8deb5d8-2cb6-47ad-87b2-999149b4b870%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Spencer W]

Mine run from 18v low brightness to 35v for full brightness for the last 3 
years and have had no issues. 

Sent from my iPhone

 On Nov 19, 2013, at 4:16 PM, Gideon Wackers 
 gideon.wack...@student.uhasselt.be wrote:
 
 Does anyone know whether it is a bad idea to go below the recommended 
 multiplexing voltage as mentioned in Adams comment??
 
 Op dinsdag 19 november 2013 23:01:33 UTC+1 schreef Adam Jacobs:
 
 FYI David: 
On the clock that I built with IV-11 tubes, I initially started with 
 an anode voltage of 60v; which is the median multiplexed voltage as per 
 this datasheet: http://www.tromop.eu/cms/media/IV-11%20datasheet.pdf and 
 a 1/6 duty cycle (16.67%). That clock was bright. Couldn't sleep in the 
 room with it running, way too bright. I tried lowering the anode voltage 
 supply to 50v, which is the minimum voltage listed in the datasheet for 
 multiplexed mode. This helped, but not enough; not by a long shot. 
So, then I started lowering duty cycle. I can't remember how low I 
 eventually took it, but I soon realized that I wouldn't be able to get 
 the brightness as low as I needed without introducing some very 
 noticeable flicker. So, I moved the voltage back to 60v and the duty 
 cycle back to 1/6 and moved the clock to a much brighter location. Works 
 perfect. :) FYI, this was with the filament @ 1.5vdc. I don't know 
 enough about VFDs to know if lowering the filament voltage might have 
 helped. 
I think that one of the features of Vacuum Fluorescent Display is 
 brightness. To paraphrase someone wiser than me: If you find yourself 
 thinking up more and more convoluted mechanisms for making it work, then 
 that's often an indicator that you're barking up the wrong tree. 
 
 -Adam 
 
 On 11/19/2013 12:48 PM, David Forbes wrote: 
  
  
  Also, if your VFD is too bright, you can reduce the brightness by 
  reducing the duty cycle, which is done by turning off the anodes on 
  for some time in each cycle. 
 
 
 -- 
 You received this message because you are subscribed to the Google Groups 
 neonixie-l group.
 To unsubscribe from this group and stop receiving emails from it, send an 
 email to neonixie-l+unsubscr...@googlegroups.com.
 To post to this group, send an email to neonixie-l@googlegroups.com.
 To view this discussion on the web, visit 
 https://groups.google.com/d/msgid/neonixie-l/b8deb5d8-2cb6-47ad-87b2-999149b4b870%40googlegroups.com.
 For more options, visit https://groups.google.com/groups/opt_out.

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/9397A3A6-AB80-4B4E-A914-31B1D56975E7%40yahoo.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[John Rehwinkel]

 Does anyone know whether it is a bad idea to go below the recommended 
 multiplexing voltage as mentioned in Adams comment??

It won't damage the VFD or anything, but it slows down the electrons, so you 
could get ghosting while multiplexing.  I'm guessing the numbers in the 
datasheet are to produce the rated brightness.  Since you don't want the rated 
brightness, I'm guessing you're fine with multiplexing it with reduced voltage. 
 Reducing the duty cycle should work too, naturally.

- John

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/F3D78D67-10BC-496B-A44D-4C3E556A3BE7%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD clock, some questions

[Gideon Wackers]

If there is one thing I like it is an answer like that :)

I tried to request three samples of the supertex drivers, we'll see if they 
grant me some. 

Thank you all for the comments, suggestions and solutions up to this point. 
I got more (practical) answers here in less than 24 hours than two weeks of 
forums got me. 

Op dinsdag 19 november 2013 23:38:09 UTC+1 schreef Spencer:

 Mine run from 18v low brightness to 35v for full brightness for the last 3 
 years and have had no issues. 

 Sent from my iPhone

 On Nov 19, 2013, at 4:16 PM, Gideon Wackers 
 gideon@student.uhasselt.be javascript: wrote:

 Does anyone know whether it is a bad idea to go below the recommended 
 multiplexing voltage as mentioned in Adams comment??

 Op dinsdag 19 november 2013 23:01:33 UTC+1 schreef Adam Jacobs:

 FYI David: 
On the clock that I built with IV-11 tubes, I initially started with 
 an anode voltage of 60v; which is the median multiplexed voltage as per 
 this datasheet: http://www.tromop.eu/cms/media/IV-11%20datasheet.pdf and 
 a 1/6 duty cycle (16.67%). That clock was bright. Couldn't sleep in the 
 room with it running, way too bright. I tried lowering the anode voltage 
 supply to 50v, which is the minimum voltage listed in the datasheet for 
 multiplexed mode. This helped, but not enough; not by a long shot. 
So, then I started lowering duty cycle. I can't remember how low I 
 eventually took it, but I soon realized that I wouldn't be able to get 
 the brightness as low as I needed without introducing some very 
 noticeable flicker. So, I moved the voltage back to 60v and the duty 
 cycle back to 1/6 and moved the clock to a much brighter location. Works 
 perfect. :) FYI, this was with the filament @ 1.5vdc. I don't know 
 enough about VFDs to know if lowering the filament voltage might have 
 helped. 
I think that one of the features of Vacuum Fluorescent Display is 
 brightness. To paraphrase someone wiser than me: If you find yourself 
 thinking up more and more convoluted mechanisms for making it work, then 
 that's often an indicator that you're barking up the wrong tree. 

 -Adam 

 On 11/19/2013 12:48 PM, David Forbes wrote: 
  
  
  Also, if your VFD is too bright, you can reduce the brightness by 
  reducing the duty cycle, which is done by turning off the anodes on 
  for some time in each cycle. 
  

  -- 
 You received this message because you are subscribed to the Google Groups 
 neonixie-l group.
 To unsubscribe from this group and stop receiving emails from it, send an 
 email to neonixie-l+...@googlegroups.com javascript:.
 To post to this group, send an email to neoni...@googlegroups.comjavascript:
 .
 To view this discussion on the web, visit 
 https://groups.google.com/d/msgid/neonixie-l/b8deb5d8-2cb6-47ad-87b2-999149b4b870%40googlegroups.com
 .
 For more options, visit https://groups.google.com/groups/opt_out.



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/29f3b01e-31a7-4428-89ab-a7add002b654%40googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD

[vfdclock]

try to visit my website: http://vfdclock.jimdo.com.you can find answers on 
the web site.

在 2013年7月30日星期二UTC+8上午10时25分58秒，Spencer写道：

 After spending several days playing with the negative voltages and testing 
 it, it doesn't work as I was hoping. It seems that a lot of people use AC 
 instead of DC and I can't find an example that uses DC for negative 
 voltages. This was the closest I could find, 
 http://threeneurons.wordpress.com/vfd-stuff/ , but it looks like its AC.

 I was working with 2 tubes in series with a 30 ohm 2W resistor that has 
 +5V applied to the first filament and then the other end is grounded, and 
 the grid/anode was fed +30V with a HV5812 shift register. 

 I put the -27V on the first end and GND on the other end of the filament, 
 it lit up pretty bright on the filament and I tried with different resistor 
 values but even the 2W resistors were heating up and the brightness of the 
 segments wasn't there.

 I then tried -27V on the first filament and different combinations of -27V 
 and the +5V with resistors on the other end of the filament and the anodes 
 were grounded, but nothing was working or it was very dim segments. 

 While I would love to get this working, It looks like I should use a 
 second MCU to handle the display/boost and another to handle all the other 
 operations.

 Thank you everyone,

 Spencer

   --
  *From:* Spencer W upnxw...@yahoo.com javascript:
 *To:* neoni...@googlegroups.com javascript: 
 neoni...@googlegroups.comjavascript: 

 *Sent:* Monday, July 22, 2013 7:33 PM
 *Subject:* Re: [neonixie-l] IV-11 VFD
  
 So many ways to tackle one problem. I get stubborn when one way doesn't 
 work right the first time and will spend days getting it to work.

 I'm trying to keep the interrupts free for some rotary encoders so either 
 the pt6311 or the secondary MCU will be he way to go. Plus if I get the 
 pt6311 working for this, I have a bunch of different tubes that I can use 
 this one.

 I have been eyeing the IV-17 for some projects and would love to see it 
 work with this.

 Either way, once I get everything figured out, I'll share with the group 
 so someone else doesn't need to do the leg work.

 -spencer

 Sent from my iPhone

 On Jul 22, 2013, at 4:42 PM, Bill van Dijk 
 bvd...@xplornet.comjavascript: 
 wrote:

 Spencer,
  
 there are a couple of (actually many) options. I have another clock that 
 also multiplexes 60 LEDS as well as 6 7-segment displays in a 1-6 MUX. I 
 control the multiplexing of the tubes by interrupts at about 300Hz, which 
 ensures better timing. The power supply is probably more tolerant to a 
 couple of missed or late cycles without any visual effects. Shift registers 
 are also great tools for multiplexing, especially when used in conjunction 
 with a BCD to 7 segment decoder. That way you can completely control 6 
 tubes with only one 8-bit port. I would suggest if you do feel inclined to 
 add a small MCU to help out, dedicated it to the power supply, and keep all 
 the clock functions as well as the multiplexing in the main MCU. 
  
 So many options. :-)
  
 Bill v. Dijk
  
 *From:* neoni...@googlegroups.com javascript: [
 mailto:n...@googlegroups.com javascript:] *On Behalf Of *Spencer
 *Sent:* Sunday, July 21, 2013 2:07 PM
 *To:* neoni...@googlegroups.com javascript:
 *Subject:* Re: [neonixie-l] IV-11 VFD
  
 Thanks for the schematic. It would be overkill if it was just for a clock 
 but I want to save cycles on the MCU since it was multiplexing the tubes 
 and boosting the voltage. I was taking cycles away from the MCU and it was 
 causing flickering. I looked at either a PT6311 or having a dedicated 
 attiny to run the multiplex/booting and feeding via serial the tube display.
  
 So it just looks like the filament voltage is biased (is that the current 
 term?) to the grid voltage. So -18v filament one end and -20 the other end 
 and grid/anode is -20v. I am using MC34063 inverted to generate the 
 voltage. I'll give it a shot it and see what happens!
  
 --
 *From:* Bill van Dijk bvd...@xplornet.com javascript:
 *To:* neoni...@googlegroups.com javascript: 
 *Sent:* Sunday, July 21, 2013 7:07 AM
 *Subject:* RE: [neonixie-l] IV-11 VFD
  
 Spencer,
  
 Attached is the schematic for my IV17 clock with a PT6311. It is a chip 
 that takes a bit of figuring out, also on the software side. My clock 
 displays time (why not eh?) and the full date in a marquee format as well 
 as ambient temperature. I would suggest the PT6311 is possibly a bit of 
 overkill for a 7 segment based clock design.
  
 Bill v. Dijk
  
 *From:* neoni...@googlegroups.com javascript: [
 mailto:n...@googlegroups.com javascript:] *On Behalf Of *Spencer
 *Sent:* Saturday, July 20, 2013 2:29 PM
 *To:* neoni...@googlegroups.com javascript:
 *Subject:* Re: [neonixie-l] IV-11 VFD
  
 Got it working! It lights up now and it looks like I will have to change 
 the filament resistor. I was using a 30

RE: [neonixie-l] IV-11 VFD

[Bill van Dijk]

Spencer,

 

there are a couple of (actually many) options. I have another clock that
also multiplexes 60 LEDS as well as 6 7-segment displays in a 1-6 MUX. I
control the multiplexing of the tubes by interrupts at about 300Hz, which
ensures better timing. The power supply is probably more tolerant to a
couple of missed or late cycles without any visual effects. Shift registers
are also great tools for multiplexing, especially when used in conjunction
with a BCD to 7 segment decoder. That way you can completely control 6 tubes
with only one 8-bit port. I would suggest if you do feel inclined to add a
small MCU to help out, dedicated it to the power supply, and keep all the
clock functions as well as the multiplexing in the main MCU. 

 

So many options. :-)

 

Bill v. Dijk

 

From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On
Behalf Of Spencer
Sent: Sunday, July 21, 2013 2:07 PM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] IV-11 VFD

 

Thanks for the schematic. It would be overkill if it was just for a clock
but I want to save cycles on the MCU since it was multiplexing the tubes and
boosting the voltage. I was taking cycles away from the MCU and it was
causing flickering. I looked at either a PT6311 or having a dedicated attiny
to run the multiplex/booting and feeding via serial the tube display.

 

So it just looks like the filament voltage is biased (is that the current
term?) to the grid voltage. So -18v filament one end and -20 the other end
and grid/anode is -20v. I am using MC34063 inverted to generate the voltage.
I'll give it a shot it and see what happens!

 

  _  

From: Bill van Dijk bvd...@xplornet.com
To: neonixie-l@googlegroups.com 
Sent: Sunday, July 21, 2013 7:07 AM
Subject: RE: [neonixie-l] IV-11 VFD

 

Spencer,

 

Attached is the schematic for my IV17 clock with a PT6311. It is a chip that
takes a bit of figuring out, also on the software side. My clock displays
time (why not eh?) and the full date in a marquee format as well as ambient
temperature. I would suggest the PT6311 is possibly a bit of overkill for a
7 segment based clock design.

 

Bill v. Dijk

 

From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On
Behalf Of Spencer
Sent: Saturday, July 20, 2013 2:29 PM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] IV-11 VFD

 

Got it working! It lights up now and it looks like I will have to change the
filament resistor. I was using a 30 ohm with +5V but ooo boy does it get
bright with that. I'll drop it down to around +1.5V and can take it from
here.

 

Thanks again.

 

  _  

From: John Rehwinkel jreh...@mac.com
To: neonixie-l@googlegroups.com 
Sent: Saturday, July 20, 2013 12:54 PM
Subject: Re: [neonixie-l] IV-11 VFD


 Thanks for the reply. I put the -25v on pins 1 and 11 (cathodes) and GND
on pin 2(grid) and GND on a random anode to see if it would light up and
nothing illuminated.

The filament needs to be hot to emit electrons for the VFD to operate - this
is normally accomplished by heating it electrically.  I did kind of gloss
over this -- you have to have voltage across the filament as well - this is
true no matter how the other voltages are supplied.  The ideal method is
to have a small center-tapped transformer providing the AC filament voltage
(generally something between half a volt to a few volts), and hook the -25V
to the center tap.  I often use a generic 6.3V filament transformer, with
series resistors to drop the voltage to whatever the VFD filament needs.
Some people don't want to bother with an AC filament voltage, and just run
it with DC - this will work, but can lead to brightness gradients in some
tubes.

So, just to light something, at a minimum, you'll need -25 volts at one end
of the filament, -(25 + filament voltage) at the other end of the filament,
and 0V at the grid(s) and anode(s) you want to light.

- John

-- 
You received this message because you are subscribed to the Google Groups
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an
email to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/C81F0687-BB98-4FAD-A200-7450550
41C3E%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.



-- 
You received this message because you are subscribed to the Google Groups
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an
email to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/1374344910.82573.YahooMailNeo%4
0web142601.mail.bf1.yahoo.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

-- 
You received this message because you are subscribed to the Google

Re: [neonixie-l] IV-11 VFD

[Spencer W]

So many ways to tackle one problem. I get stubborn when one way doesn't work 
right the first time and will spend days getting it to work.

I'm trying to keep the interrupts free for some rotary encoders so either the 
pt6311 or the secondary MCU will be he way to go. Plus if I get the pt6311 
working for this, I have a bunch of different tubes that I can use this one.

I have been eyeing the IV-17 for some projects and would love to see it work 
with this.

Either way, once I get everything figured out, I'll share with the group so 
someone else doesn't need to do the leg work.

-spencer

Sent from my iPhone

On Jul 22, 2013, at 4:42 PM, Bill van Dijk bvd...@xplornet.com wrote:

 Spencer,
  
 there are a couple of (actually many) options. I have another clock that also 
 multiplexes 60 LEDS as well as 6 7-segment displays in a 1-6 MUX. I control 
 the multiplexing of the tubes by interrupts at about 300Hz, which ensures 
 better timing. The power supply is probably more tolerant to a couple of 
 missed or late cycles without any visual effects. Shift registers are also 
 great tools for multiplexing, especially when used in conjunction with a BCD 
 to 7 segment decoder. That way you can completely control 6 tubes with only 
 one 8-bit port. I would suggest if you do feel inclined to add a small MCU to 
 help out, dedicated it to the power supply, and keep all the clock functions 
 as well as the multiplexing in the main MCU.
  
 So many options. :-)
  
 Bill v. Dijk
  
 From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On 
 Behalf Of Spencer
 Sent: Sunday, July 21, 2013 2:07 PM
 To: neonixie-l@googlegroups.com
 Subject: Re: [neonixie-l] IV-11 VFD
  
 Thanks for the schematic. It would be overkill if it was just for a clock but 
 I want to save cycles on the MCU since it was multiplexing the tubes and 
 boosting the voltage. I was taking cycles away from the MCU and it was 
 causing flickering. I looked at either a PT6311 or having a dedicated attiny 
 to run the multiplex/booting and feeding via serial the tube display.
  
 So it just looks like the filament voltage is biased (is that the current 
 term?) to the grid voltage. So -18v filament one end and -20 the other end 
 and grid/anode is -20v. I am using MC34063 inverted to generate the voltage. 
 I'll give it a shot it and see what happens!
  
 From: Bill van Dijk bvd...@xplornet.com
 To: neonixie-l@googlegroups.com 
 Sent: Sunday, July 21, 2013 7:07 AM
 Subject: RE: [neonixie-l] IV-11 VFD
  
 Spencer,
  
 Attached is the schematic for my IV17 clock with a PT6311. It is a chip that 
 takes a bit of figuring out, also on the software side. My clock displays 
 time (why not eh?) and the full date in a marquee format as well as ambient 
 temperature. I would suggest the PT6311 is possibly a bit of overkill for a 7 
 segment based clock design.
  
 Bill v. Dijk
  
 From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On 
 Behalf Of Spencer
 Sent: Saturday, July 20, 2013 2:29 PM
 To: neonixie-l@googlegroups.com
 Subject: Re: [neonixie-l] IV-11 VFD
  
 Got it working! It lights up now and it looks like I will have to change the 
 filament resistor. I was using a 30 ohm with +5V but ooo boy does it get 
 bright with that. I'll drop it down to around +1.5V and can take it from here.
  
 Thanks again.
  
 From: John Rehwinkel jreh...@mac.com
 To: neonixie-l@googlegroups.com 
 Sent: Saturday, July 20, 2013 12:54 PM
 Subject: Re: [neonixie-l] IV-11 VFD
 
  Thanks for the reply. I put the -25v on pins 1 and 11 (cathodes) and GND on 
  pin 2(grid) and GND on a random anode to see if it would light up and 
  nothing illuminated.
 
 The filament needs to be hot to emit electrons for the VFD to operate - this 
 is normally accomplished by heating it electrically.  I did kind of gloss 
 over this -- you have to have voltage across the filament as well - this is 
 true no matter how the other voltages are supplied.  The ideal method is to 
 have a small center-tapped transformer providing the AC filament voltage 
 (generally something between half a volt to a few volts), and hook the -25V 
 to the center tap.  I often use a generic 6.3V filament transformer, with 
 series resistors to drop the voltage to whatever the VFD filament needs.  
 Some people don't want to bother with an AC filament voltage, and just run it 
 with DC - this will work, but can lead to brightness gradients in some tubes.
 
 So, just to light something, at a minimum, you'll need -25 volts at one end 
 of the filament, -(25 + filament voltage) at the other end of the filament, 
 and 0V at the grid(s) and anode(s) you want to light.
 
 - John
 
 -- 
 You received this message because you are subscribed to the Google Groups 
 neonixie-l group.
 To unsubscribe from this group and stop receiving emails from it, send an 
 email to neonixie-l+unsubscr...@googlegroups.com.
 To post to this group, send an email to neonixie-l@googlegroups.com.
 To view

Re: [neonixie-l] IV-11 VFD

[Spencer]

Thanks for the schematic. It would be overkill if it was just for a clock but I 
want to save cycles on the MCU since it was multiplexing the tubes and boosting 
the voltage. I was taking cycles away from the MCU and it was causing 
flickering. I looked at either a PT6311 or having a dedicated attiny to run the 
multiplex/booting and feeding via serial the tube display.

So it just looks like the filament voltage is biased (is that the current 
term?) to the grid voltage. So -18v filament one end and -20 the other end and 
grid/anode is -20v. I am using MC34063 inverted to generate the voltage. I'll 
give it a shot it and see what happens!



 From: Bill van Dijk bvd...@xplornet.com
To: neonixie-l@googlegroups.com 
Sent: Sunday, July 21, 2013 7:07 AM
Subject: RE: [neonixie-l] IV-11 VFD
 


Spencer,
 
Attached is the schematic for my IV17 clock with a PT6311. It is a chip that 
takes a bit of figuring out, also on the software side. My clock displays time 
(why not eh?) and the full date in a marquee format as well as ambient 
temperature. I would suggest the PT6311 is possibly a bit of overkill for a 7 
segment based clock design.
 
Bill v. Dijk
 
From:neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On Behalf 
Of Spencer
Sent: Saturday, July 20, 2013 2:29 PM
To: neonixie-l@googlegroups.com
Subject: Re: [neonixie-l] IV-11 VFD
 
Got it working! It lights up now and it looks like I will have to change the 
filament resistor. I was using a 30 ohm with +5V but ooo boy does it get bright 
with that. I'll drop it down to around +1.5V and can take it from here.
 
Thanks again.
 



From:John Rehwinkel jreh...@mac.com
To: neonixie-l@googlegroups.com 
Sent: Saturday, July 20, 2013 12:54 PM
Subject: Re: [neonixie-l] IV-11 VFD

 Thanks for the reply. I put the -25v on pins 1 and 11 (cathodes) and GND on 
 pin 2(grid) and GND on a random anode to see if it would light up and nothing 
 illuminated.

The filament needs to be hot to emit electrons for the VFD to operate - this is 
normally accomplished by heating it electrically.  I did kind of gloss over 
this -- you have to have voltage across the filament as well - this is true no 
matter how the other voltages are supplied.  The ideal method is to have a 
small center-tapped transformer providing the AC filament voltage (generally 
something between half a volt to a few volts), and hook the -25V to the center 
tap.  I often use a generic 6.3V filament transformer, with series resistors to 
drop the voltage to whatever the VFD filament needs.  Some people don't want to 
bother with an AC filament voltage, and just run it with DC - this will work, 
but can lead to brightness gradients in some tubes.

So, just to light something, at a minimum, you'll need -25 volts at one end of 
the filament, -(25 + filament voltage) at the other end of the filament, and 0V 
at the grid(s) and anode(s) you want to light.

- John

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/C81F0687-BB98-4FAD-A200-745055041C3E%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.



-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/1374344910.82573.YahooMailNeo%40web142601.mail.bf1.yahoo.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 
-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/003001ce860a%24f3b03750%24db10a5f0%24%40com.
For more options, visit https://groups.google.com/groups/opt_out.

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/1374430022.36570.YahooMailNeo%40web142605.mail.bf1.yahoo.com.
For more options, visit https://groups.google.com/groups/opt_out.

Re: [neonixie-l] IV-11 VFD

[John Rehwinkel]

 I have discovered the PT6311 which will handle all of my multiplexing and was 
 in heaven. After reading the datasheet, I discovered that it uses a negative 
 supply for the VFD. I made a voltage inverter and tried testing it out on a 
 tube to see what the connections are. This is where I do not understand it. I 
 had been giving the tube about +25V to the grid and Anodes with the HV5812 
 but I am not sure what the connection is with the PT6311, if it even works 
 with a VFD tube for a -25 power supply. 
 
 The heater has +5V supply with an appropriate resistor in both circumstances.
 
 I put -25V on the grid and Anodes, then tried just -25V to the Anodes and the 
 grid to ground and it doesn't light up.
 
 Does anyone have any suggestions?

The VFD only cares about the difference of voltage between its elements.  So 
the grid and anode have to be more positive than the cathode to light it.  The 
PT6311 is arranged so that the cathode is run at -25V, and to turn segments on, 
the grids and anodes are pulled up to ground, making them more positive than 
the cathode.  To turn them off, it pulls then down to -25V.

I have some commercial VFD inverters from surplus companies that produce -30V, 
along with a floating center-tapped 6VAC output to power the filament.  I 
connect the -30V to the filament center tap.

The tricky part is interfacing logic to the PT6311 - sometimes it's easiest to 
float the logic supply.

- John

-- 
You received this message because you are subscribed to the Google Groups 
neonixie-l group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to neonixie-l+unsubscr...@googlegroups.com.
To post to this group, send an email to neonixie-l@googlegroups.com.
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/32F1F42D-4C7E-4B0C-9BC1-060834BA8611%40mac.com.
For more options, visit https://groups.google.com/groups/opt_out.