Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I created a separate user group 
https://groups.google.com/forum/#!forum/b7971-driver-board-user-group

for neonixie members who are interested in building a clock with b7971 
tubes using my PC board. As of now, I dont have any more PC boards. I have 
2 boards running, but we need to have more built & tested to shake-out 
problems before making any more. All of my extra boards have been given 
away, but if there is interest another batch can be made in a few months. 
There will be a charge for the boards (about 10 USD each) and shipping. I 
dont have any 7971 tubes for sale, and I bought-out my supplier.

For the 4 of you who have received (or will shortly receive) the boards, 
you should have received an invite to join. 

Although mine is controlled by a RasPi, there's no reason why it cant also 
be controlled from Arduino, FPGA, etc.

Membership is by invitation only (only to prevent spambots). I will admit 
any neonixe member. 


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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[Paolo Cravero]

Hi.


>
> The real question now is: How long can a raspi run without crashing ?
>

As all *ni systems, a RasPI can run for years unless there is a hardware
failure or overheating. I've been (silently ;) ) collecting uptimes at work
and I've seen servers that haven't rebooted for 1600+ days
(enterprise-grade computers have redundand power supplies and hard disks
that can be hot-swapped/replaced). A RPi can perform the same.


>
> Eventually I will start logging usage of each segment, on each tube, and
> use that for depoisoning. Since it's a micro SD (flash) filesystem, which
> has limited write-cycles, I have to be careful about how often I store
> runtime information. Syncing daily to the same file (appending) could cause
> wearout after several years if the OS doesn't incorporate some form of
> levelling. Doing it every 3-4 days should get me about 100 years of logging
> if the flash has 10K write-cycle endurance. Not that I will be around then
> to do anything with that
>

Well, the write-cycle count applies to each single bit of the flash memory.
So, if you're just appending data to a file, what has been written won't
change on subsequent additions. Your filesystem might have blocks of 2 kiB,
4 kiB or 8 kiB, so that's the amount of data that could change at once if
the bucket was full yet. Then there's the filesystem internals and journal
("which blocks form a file" in simple terms, the index), that could change
more often.

OTOH Linux systems log stuff all the time to disk, so that part of the
flash disk might fail before your clock log sectors.

An option could be to upload your data to some online (free) service, since
you have WiFi.

Also, have you though of implementing a purely hardware watchdog to shut
down everything in case the software hangs?

Paolo

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RE: [neonixie-l] Re: Raspberry PI controlled Nixie display

[neonixie-l]

Agree w/Paul - crontab is for periodically running things, not to start a 
daemon on system startup.

To add a little bit more to what he mentioned, you may want to have a script 
that accepts a parameter indicating if it's "start", "stop" or "restart" (e.g. 
stop then start) for the daemon. Then within the /etc/init.d/ dir you put your 
script.  It must have a standard LSB header and you run a command (see 2nd 
link) so the system knows how to connect all the parts. This way for shutdown 
(or restart) your clock code can accept a shutdown request (in your clock 
program C code catch a SIGTERM or other 'signal') and gracefully put any GPIO 
pins to a safe state before exiting. Restart is handy after you've swapped in a 
new program version. For that once in a blue moon instance when your program 
won't shut down gracefully, you can in your script also code a "kill" section 
that sends a SIGKILL to your program.

In the script you also choose at what run-level you want the clock program to 
run. Typically, that would be 2, 3 & 5.  See 
http://www.tldp.org/LDP/sag/html/run-levels-intro.html for run-level info, 
which also talks a little about the /etc/init.d/

A decent RPi example & explanation of what's needed with some shell start/stop 
code is here: 
http://raspberrywebserver.com/serveradmin/run-a-script-on-start-up.htmlI 
haven't verified it works, but the shell scripting looks OK from my Red Hat 
perspective.

Good luck and have fun!

  - Steve

-Original Message-
From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On 
Behalf Of Paul Andrews
Sent: Tuesday, June 20, 2017 8:08 AM
To: neonixie-l
Subject: Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

Good news. I had wondered about using a PI myself but was concerned with lack 
of realtimeness. BTW, in regular UNIX you would set your app up as a demon that 
runs at boot up. Crontab would not be the way to go. There should be a bunch of 
stuff in /etc/init.d or /etc/initd or something like that. You'll have to 
google the details, you should be able to specify at what stage in the boot 
process it gets run and as what user.

- Paul

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

If you want 10msec granularity, traditional Linux may not be the right 
choice.

I did quite a bit of data-gathering (See my April 14 post in this subject), 
and got 64-bit serial packets to transmit , on average, in 32usec. 
 Occasionally there is an outlier, on the order of milliseconds, due to 
system housekeeping tasks. THAT is what may clobber your 10msec fading.

My code is intentionally 'bursty'. Every second, the system clock is 
queried, then the date or time display-message is composed (message varies, 
such as time format, day, date). Once the message is composed and 
translated into segment data, the actual 128-bit serial transmission takes 
place. It's a 'flattened' subroutine with no loops or calculations that 
hammers the GPIO pins as quickly as possible to get the data send to the 
display board. Since I'm running 2 boards, I send 128 bits. The last step 
is to check the PIR sensor, if that function is enabled, and decide whether 
or not to keep the display on.

Last night while running a system update, the CPU was pegged at 100% for 
about half an hour. There was no degradation in the display. Apparently the 
task swapper in Linux gives my clock software a large enough slice so that 
it finishes; I believe the default is 100msec.

I dont have fading, but I do plan to add 'dissolving', where 
segment-changes are staged in 100msec intervals and characters morph from 
one to the next.

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Mitch]

Greg, is I/O fast enough to support cross fades? For a really smooth fade, 
I think updates must be 10ms or less.

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[Paul Andrews]

Good news. I had wondered about using a PI myself but was concerned with lack 
of realtimeness. BTW, in regular UNIX you would set your app up as a demon that 
runs at boot up. Crontab would not be the way to go. There should be a bunch of 
stuff in /etc/init.d or /etc/initd or something like that. You'll have to 
google the details, you should be able to specify at what stage in the boot 
process it gets run and as what user.

- Paul

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

Thought I would post a follow-up regarding a RasPi as a nixie controller.

So far, using a RasPi Zero W for controlling my latest nixie clock (8-tube 
b7971) has far-exceeded my expectations:

   - No 'helper' FPGA is needed; there is far more than enough horsepower 
   in the Pi to handle all of the compute, timekeeping, and serial 
   communications
   - Timekeeping is accurate; the Pi periodically syncs to a time-source on 
   the internet (no idea where). Perhaps it's from my router, which gets the 
   time elsewhere.
   - Display updates are done once per second. I have never observed my 
   display 'jump' or 'stall' +/- 1 second based on the random alignment 
   between realtime, and when the clock software updates the display. I did 
   not add any code to attempt to synchronize to realtime.
   - CPU utilization is averaging 3-4%, even when running a VNC server, 
   plus all of the Linux housekeeping tasks. There are periodic spikes of ~40% 
   each second when the clock software does it's work. No significant thermal 
   generation (less than 10 degrees F as measure with infrared thermometer)
   - Using a cheap passive IR (PIR) sensor has allowed me to shut-down the 
   tubes most of the time; the sensor is sensitive enough that I really cant 
   sneak-up on my clock without it turning on. Nor is it falsely triggering.
   - GPIO programming with WiringPi is fairly easy; there were some quirks 
   that I found and fixed when reading a digital input. Also some minor 
   documentation issues about pin-naming.
   - Being able to remotely program without attaching/removing cables, 
   power-cycle, etc is very handy. I use 'C' because it's compiled, hence 
   faster execution versus python, perl, etc.
   - Only drawback so far is the startup-time (linux boot), which is just 
   under a minute. I have not yet added the clock software into the bootup 
   process so that it auto-starts on power-up; should be easy to do in crontab 
   ? (I've done it before for a remote server; just cant remember where).
   - Without an attached RTC module, timekeeping relies on my internet 
   service and WiFi running. I have thought about adding an RTC module as a 
   backup, but it's low priority.

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

Thanks for the warning. Generally, I leave everything plugged-in 'forever', 
which is probably why I havn't had problems yet.

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[Terry Kennedy]

On Tuesday, June 6, 2017 at 1:19:05 AM UTC-4, gregebert wrote:
>
> Photo here, and short video posted to YouTube at 
> https://youtu.be/OjQeW67viXw
>

Mostly unrelated, but... I've had bad experiences with devices very similar 
to those 2 10-receptacle boxes you have mounted on the wall behind the 
clock. It was many years ago and I forget the details, but I would up 
drilling out the 4 rivets holding the case together and replacing pretty 
much all of the "guts", including the 5 duplex receptacles with much 
higher-quality ones (using real screw terminals, not push-in backwire) and 
then using sheet metal screws in the former rivet holes to reassemble the 
unit. APC used to use the push-in backwire receptacles in their 
AP9210/AP9211 strips and I never had a problem with those, so it may be low 
quality parts in the Belkin units. If you look at the online reviews you'll 
see that many of the negative reviews are for "worked for a while and then 
died".

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[blkadder]

Another option for a nixie socket/adapter would be the ones available from 
our friend Pete over at www.pvelectronics.co.uk.  Pete is very active, and 
I have used his clock kits to build several clocks.  I have also purchased 
the adapters you need to fix some of my horrible soldering jobs.  Now when 
I order a kit, I make to insure I get a few extra adapters.  His page for 
the adapters can be found here:  
http://www.pvelectronics.co.uk/index.php?main_page=index=4_11

I will be watching this thread as well as the Arduino thread.  Thanks to 
all for posting excellent information.

Ron

...Semper Fidelis...

On Monday, March 20, 2017 at 5:42:24 AM UTC-4, okniew wrote:
>
> Hello everyone!
>
>  
>
> I’m new to this group and this is my first post.
>
> I’m looking forward to design & build a particular project with Nixie 
> display, but since I’m really not an expert and just starting, I would very 
> much appreciate your help & feedback. I do have some specific questions (in 
> the end), but if you look at project goal & design principles and think of 
> better way to do things – please comment as well!
>
>  
>
> *Project goals:*
>
> A Raspberry PI controlled Nixie display, with some additional LED 
> indicators for weather conditions. Nixie display will be used to display 
> the time or temperature or humidity, depending on settings.
>
> Main assumptions:
>
> 1. 6 lamps: IN-19V ("+"/"-"), 4 x IN-14 ("0" - "9" + 2 dots), IN-19A 
> ("C"/"%") 
>
> 2. Ability to control Nixie brightness (by Raspberry PI) 
>
> 3. LED RGB back-light under each tube, with color & brightness controlled 
> (by Raspberry PI)
>
>
> The look I want to achieve:
>
>
>  
>
> *Design principles:*
>
> 1. As much as possible – use the components available on the market. I’d 
> like to avoid designing PCBs, avoid designing custom circuits, minimize 
> soldering, etc. I understand I’ll have to do those things to some extent, 
> but being a newbie, I want to minimize room for failure or issues. 
>
> 2. A single visible power supply for the whole thing, from 230V AC outlet, 
> driving all 6 nixies (180V, 30mA), Raspberry (5V, 3A) and the LEDs.
>
> 3. All components should be ideally driven by Raspberry I2C bus interface, 
> using which I could control separately: displayed value of each tube, 
> brightness of each tube, color & brightness of each LED. I think this is 
> the easiest and most versatile approach (but again – looking for 
> confirmation / other suggestions)
>
>  
>
> *Questions to start with:*
>
> 1. Are there any available to be purchased components, which you could 
> recommend, fulfilling above design principles & goals? Right now, I have 
> the Raspberry & the tubes, but nothing “in between” J
>
> 2. Do you think my idea of controlling all components via I2C bus is a 
> good idea? I want to go for the easiest and most versatile approach.
>
> 3. Are there anywhere existing sockets for IN-14 / IN-19 tubes? Or will I 
> have to solder to tubes to whatever components I select?
>
>  
>
> Thanks a lot for your help!
>

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I got my RasPi-based clock to display time last night, so proof-of-concept 
is done.

Right now, I'm using seven b7971 tubes. All of the compute-related stuff is 
done via a 'C' program running on the RasPi. I had planned on adding an 
FPGA to offload the RasPi, but so far I have not seen a need to do that.

Some of the details of the design below. I'll post a photo tonight.

RasPi Zero (yeah, the $10 US board with built-in WiFi), running raspian.
Debian-based tools/env, including gcc, and VNC
Uses wiringPi library to allow software control of the GPIO pins
Two PCB's (each with 4 sockets and current-limited direct-drive b7971 
nixies). Easy to cascade more boards if I could afford more tubes.
Serial interface (clk, data, load) via opto-isolators.
Separate +5VDC (isolated), and +185VDC (NON-isolated) supplies

Everything is working as expected; workload on the Pi is low (about 4% on 
average).
I still need to check supply-margining, signal integrity, add the colons, 
and run it on the AC-line (right now it's on an isolation transformer).
Hooray, no blue wires on the PCB ! Everything worked as expected the first 
time.
There's more work to be done with the programming, such as inserting text 
messages.
And of course, I need to make a case for it.

Being able to remotely access it for software development is really handy; 
even after it's locked inside the case I can still login and add features.

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[Charles MacDonald]

On 17-04-15 02:55 AM, Nick wrote:

You could always use a genuine real-time o/s like ChibiOS/RT ..


At one time their was a group working on a real time linux kernel...

https://www.linux.com/blog/intro-real-time-linux-embedded-developers

https://wiki.archlinux.org/index.php/Realtime_kernel

would that be close enough?

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cm...@zeusprune.ca  Just Beyond the Fringe
No Microsoft Products were used in sending this e-mail.

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[blave]

This is how I did it. https://www.youtube.com/watch?v=9kbrIwxNr9g

have fun,

Dave B.

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Nick]

You could always use a genuine real-time o/s like ChibiOS/RT ..

Nick

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I ran a few more tests on serializing a 64-bit stream using C-language and 
the wiringPi library.
Typically, I'm getting around 32usec (measured on a scope) to send the 
64-bit burst, which is decent for software-controlled GPIO's.

There are timers available in wiringPi, but I found they are not accurate. 
A burst that measures ~32usec on my scope is around 22usec per the micros() 
call.

Despite it's inaccuracy, it's still useful for generating histogram data on 
transmit times. As GastonP pointed out, timing is non-deterministic in 
Linux. After numerous runs I did see a case where it took 10msec to 
complete the transmit. The single outlier really skewed the avg TX time.

Bottom line is that the RasPi is usable for many, but not all, control 
applications. A clock should be OK; engine controller ? No way.
All of my clocks to-date are at least as reliable as the electric utility 
(never had logic or FPGA crash on me); not sure if RasPi has similar 
reliability / availability.

greg@rpi0w001:/proj1/pigpio/src $ ../exe/speedtest_gpio_tx64
400 Loops. Max_time = 10083usec, Min_time = 18usec, Avg_time = 45.69usec
   0 to   20: N = 161
  20 to   25: N = 219
  25 to   30: N = 18
  30 to   35: N = 0
  35 to   40: N = 1
  40 to   45: N = 0
  45 to   50: N = 0
  50 to   60: N = 0
  60 to   70: N = 0
  70 to  100: N = 0
 100 to  150: N = 0
 150 to  200: N = 0
 200 to  300: N = 0
 300 to  400: N = 0
 400 to  500: N = 0
 500 to  750: N = 0
 750 to 1000: N = 0
1000 to 2000: N = 0
Over2000: N = 1



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[neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I have an FPGA as my 'Plan B', in case the there isn't enough 
predictability in the Pi to display time down to the second. It wouldn't be 
much work to modify the Verilog code I did for my previous clock to allow 
the Pi to handle daylight savings, insert text messages, and possibly 
correct for time-drift (that DS3232 is really accurate..).

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[GastonP]

On Saturday, April 8, 2017 at 4:02:13 AM UTC-3, gregebert wrote:
>
> UPDATE: I have my RasPi Zero W running nicely as a headless system w/ 
> Raspian.
>
> I'm satisfied to the point I wont pursue Arduino anymore.
> Having a $10 Linux-based platform that I can log into wirelessly & 
> remotely is really incredible.
>


Just be aware that Linux is not a real time operating system, so anything 
that is time-sensitive has high risk of those timings eventually not being 
respected.
I use one of the multiple Pi lookalikes just out of cost considerations 
(OrangePi).
For tasks that do not require much processing grunt I go for the Texas 
Instruments family of mixed signal processors, and having AVR being 
recently acquired by Microchip gives me the sense that Arduino's final day 
is coming soon.

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I'm just using C, and so far I have not chosen a development tool. The info 
I found on sparkfun mentions Geany (and it's included in the current 
raspian image), so I will try that first.

There are sample programs included in the wiringPi distro for I2C and SPI. 
Have not tried either yet, but will eventually test-out I2C with a DS3232 
clock (so I have accurate time in case my internet goes down).

The GPIO connector is 40 pins (some are power and GND), which leaves 28 
usable GPIO pins. If you want to use SPI and/or I2C, some of those 28 
gpio's are mapped to SPI or I2C so plan your pinout carefully before making 
a PC board.

I've sidestepped the GPIO pin-count issue by going serial to the nixie 
drivers (74CH595+NPN current limiter). In the end, though, my b7971 project 
uses direct-drive.

https://learn.sparkfun.com/tutorials/raspberry-gpio


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[neonixie-l] Re: Raspberry PI controlled Nixie display

['Dave' via neonixie-l]

These work great.

If anyone wants to try one, I have some extra PCBs I can sell.


On Thursday, March 30, 2017 at 6:10:07 AM UTC-4, okniew wrote:
>
> I also found 1 more place having exactly what I was looking for, although 
> at a rather steep price..
>
> https://switchmodedesign.com/collections/arduino-shields/products/smart-nixie-tube
>
> Have you ever had any experiences with those kits? 
>
> W dniu poniedziałek, 20 marca 2017 10:42:24 UTC+1 użytkownik okniew 
> napisał:
>>
>> Hello everyone!
>>
>>  
>>
>> I’m new to this group and this is my first post.
>>
>> I’m looking forward to design & build a particular project with Nixie 
>> display, but since I’m really not an expert and just starting, I would very 
>> much appreciate your help & feedback. I do have some specific questions (in 
>> the end), but if you look at project goal & design principles and think of 
>> better way to do things – please comment as well!
>>
>>  
>>
>> *Project goals:*
>>
>> A Raspberry PI controlled Nixie display, with some additional LED 
>> indicators for weather conditions. Nixie display will be used to display 
>> the time or temperature or humidity, depending on settings.
>>
>> Main assumptions:
>>
>> 1. 6 lamps: IN-19V ("+"/"-"), 4 x IN-14 ("0" - "9" + 2 dots), IN-19A 
>> ("C"/"%") 
>>
>> 2. Ability to control Nixie brightness (by Raspberry PI) 
>>
>> 3. LED RGB back-light under each tube, with color & brightness controlled 
>> (by Raspberry PI)
>>
>>
>> The look I want to achieve:
>>
>>
>>  
>>
>> *Design principles:*
>>
>> 1. As much as possible – use the components available on the market. I’d 
>> like to avoid designing PCBs, avoid designing custom circuits, minimize 
>> soldering, etc. I understand I’ll have to do those things to some extent, 
>> but being a newbie, I want to minimize room for failure or issues. 
>>
>> 2. A single visible power supply for the whole thing, from 230V AC outlet, 
>> driving all 6 nixies (180V, 30mA), Raspberry (5V, 3A) and the LEDs.
>>
>> 3. All components should be ideally driven by Raspberry I2C bus 
>> interface, using which I could control separately: displayed value of each 
>> tube, brightness of each tube, color & brightness of each LED. I think this 
>> is the easiest and most versatile approach (but again – looking for 
>> confirmation / other suggestions)
>>
>>  
>>
>> *Questions to start with:*
>>
>> 1. Are there any available to be purchased components, which you could 
>> recommend, fulfilling above design principles & goals? Right now, I have 
>> the Raspberry & the tubes, but nothing “in between” J
>>
>> 2. Do you think my idea of controlling all components via I2C bus is a 
>> good idea? I want to go for the easiest and most versatile approach.
>>
>> 3. Are there anywhere existing sockets for IN-14 / IN-19 tubes? Or will I 
>> have to solder to tubes to whatever components I select?
>>
>>  
>>
>> Thanks a lot for your help!
>>
>

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

[Dylan Distasio]

Although it will not address the +, you may want to look at these.  I have
not used these personally but on paper I think they may be close to what
you want:

http://cathodecreations.com/index.php?route=product/product=59_61_id=53


On Mar 30, 2017 6:10 AM, "okniew"  wrote:

I also found 1 more place having exactly what I was looking for, although
at a rather steep price..
https://switchmodedesign.com/collections/arduino-shields/
products/smart-nixie-tube

Have you ever had any experiences with those kits?

W dniu poniedziałek, 20 marca 2017 10:42:24 UTC+1 użytkownik okniew napisał:

> Hello everyone!
>
>
>
> I’m new to this group and this is my first post.
>
> I’m looking forward to design & build a particular project with Nixie
> display, but since I’m really not an expert and just starting, I would very
> much appreciate your help & feedback. I do have some specific questions (in
> the end), but if you look at project goal & design principles and think of
> better way to do things – please comment as well!
>
>
>
> *Project goals:*
>
> A Raspberry PI controlled Nixie display, with some additional LED
> indicators for weather conditions. Nixie display will be used to display
> the time or temperature or humidity, depending on settings.
>
> Main assumptions:
>
> 1. 6 lamps: IN-19V ("+"/"-"), 4 x IN-14 ("0" - "9" + 2 dots), IN-19A
> ("C"/"%")
>
> 2. Ability to control Nixie brightness (by Raspberry PI)
>
> 3. LED RGB back-light under each tube, with color & brightness controlled
> (by Raspberry PI)
>
>
> The look I want to achieve:
>
>
>
>
> *Design principles:*
>
> 1. As much as possible – use the components available on the market. I’d
> like to avoid designing PCBs, avoid designing custom circuits, minimize
> soldering, etc. I understand I’ll have to do those things to some extent,
> but being a newbie, I want to minimize room for failure or issues.
>
> 2. A single visible power supply for the whole thing, from 230V AC outlet,
> driving all 6 nixies (180V, 30mA), Raspberry (5V, 3A) and the LEDs.
>
> 3. All components should be ideally driven by Raspberry I2C bus interface,
> using which I could control separately: displayed value of each tube,
> brightness of each tube, color & brightness of each LED. I think this is
> the easiest and most versatile approach (but again – looking for
> confirmation / other suggestions)
>
>
>
> *Questions to start with:*
>
> 1. Are there any available to be purchased components, which you could
> recommend, fulfilling above design principles & goals? Right now, I have
> the Raspberry & the tubes, but nothing “in between” J
>
> 2. Do you think my idea of controlling all components via I2C bus is a
> good idea? I want to go for the easiest and most versatile approach.
>
> 3. Are there anywhere existing sockets for IN-14 / IN-19 tubes? Or will I
> have to solder to tubes to whatever components I select?
>
>
>
> Thanks a lot for your help!
>
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[neonixie-l] Re: Raspberry PI controlled Nixie display

[okniew]

I also found 1 more place having exactly what I was looking for, although 
at a rather steep price..
https://switchmodedesign.com/collections/arduino-shields/products/smart-nixie-tube

Have you ever had any experiences with those kits? 

W dniu poniedziałek, 20 marca 2017 10:42:24 UTC+1 użytkownik okniew napisał:
>
> Hello everyone!
>
>  
>
> I’m new to this group and this is my first post.
>
> I’m looking forward to design & build a particular project with Nixie 
> display, but since I’m really not an expert and just starting, I would very 
> much appreciate your help & feedback. I do have some specific questions (in 
> the end), but if you look at project goal & design principles and think of 
> better way to do things – please comment as well!
>
>  
>
> *Project goals:*
>
> A Raspberry PI controlled Nixie display, with some additional LED 
> indicators for weather conditions. Nixie display will be used to display 
> the time or temperature or humidity, depending on settings.
>
> Main assumptions:
>
> 1. 6 lamps: IN-19V ("+"/"-"), 4 x IN-14 ("0" - "9" + 2 dots), IN-19A 
> ("C"/"%") 
>
> 2. Ability to control Nixie brightness (by Raspberry PI) 
>
> 3. LED RGB back-light under each tube, with color & brightness controlled 
> (by Raspberry PI)
>
>
> The look I want to achieve:
>
>
>  
>
> *Design principles:*
>
> 1. As much as possible – use the components available on the market. I’d 
> like to avoid designing PCBs, avoid designing custom circuits, minimize 
> soldering, etc. I understand I’ll have to do those things to some extent, 
> but being a newbie, I want to minimize room for failure or issues. 
>
> 2. A single visible power supply for the whole thing, from 230V AC outlet, 
> driving all 6 nixies (180V, 30mA), Raspberry (5V, 3A) and the LEDs.
>
> 3. All components should be ideally driven by Raspberry I2C bus interface, 
> using which I could control separately: displayed value of each tube, 
> brightness of each tube, color & brightness of each LED. I think this is 
> the easiest and most versatile approach (but again – looking for 
> confirmation / other suggestions)
>
>  
>
> *Questions to start with:*
>
> 1. Are there any available to be purchased components, which you could 
> recommend, fulfilling above design principles & goals? Right now, I have 
> the Raspberry & the tubes, but nothing “in between” J
>
> 2. Do you think my idea of controlling all components via I2C bus is a 
> good idea? I want to go for the easiest and most versatile approach.
>
> 3. Are there anywhere existing sockets for IN-14 / IN-19 tubes? Or will I 
> have to solder to tubes to whatever components I select?
>
>  
>
> Thanks a lot for your help!
>

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[okniew]

It took me some time to answer, been quite busy with my work.
Still, thanks a lot for all your answers!

@Nick - nice suggestions, thanks for sharing the links.
@Alic - yes, it has to RPI, main reason for this is - I already bought it :)
@Tomasz Kowalczyk - thank you for all the information, indeed there are 
IN-14 and IN-19 boards at OSH park. As for the remaining part of the answer 
- lots of information to digest :) As I mentioned initially, I prefer to 
use ready and available on the markets elements, but surely your answer is 
inspiring ;)

Lots of information to process.
Any other recommendations and ideas will be much appreciated!


W dniu poniedziałek, 20 marca 2017 10:42:24 UTC+1 użytkownik okniew napisał:
>
> Hello everyone!
>
>  
>
> I’m new to this group and this is my first post.
>
> I’m looking forward to design & build a particular project with Nixie 
> display, but since I’m really not an expert and just starting, I would very 
> much appreciate your help & feedback. I do have some specific questions (in 
> the end), but if you look at project goal & design principles and think of 
> better way to do things – please comment as well!
>
>  
>
> *Project goals:*
>
> A Raspberry PI controlled Nixie display, with some additional LED 
> indicators for weather conditions. Nixie display will be used to display 
> the time or temperature or humidity, depending on settings.
>
> Main assumptions:
>
> 1. 6 lamps: IN-19V ("+"/"-"), 4 x IN-14 ("0" - "9" + 2 dots), IN-19A 
> ("C"/"%") 
>
> 2. Ability to control Nixie brightness (by Raspberry PI) 
>
> 3. LED RGB back-light under each tube, with color & brightness controlled 
> (by Raspberry PI)
>
>
> The look I want to achieve:
>
>
>  
>
> *Design principles:*
>
> 1. As much as possible – use the components available on the market. I’d 
> like to avoid designing PCBs, avoid designing custom circuits, minimize 
> soldering, etc. I understand I’ll have to do those things to some extent, 
> but being a newbie, I want to minimize room for failure or issues. 
>
> 2. A single visible power supply for the whole thing, from 230V AC outlet, 
> driving all 6 nixies (180V, 30mA), Raspberry (5V, 3A) and the LEDs.
>
> 3. All components should be ideally driven by Raspberry I2C bus interface, 
> using which I could control separately: displayed value of each tube, 
> brightness of each tube, color & brightness of each LED. I think this is 
> the easiest and most versatile approach (but again – looking for 
> confirmation / other suggestions)
>
>  
>
> *Questions to start with:*
>
> 1. Are there any available to be purchased components, which you could 
> recommend, fulfilling above design principles & goals? Right now, I have 
> the Raspberry & the tubes, but nothing “in between” J
>
> 2. Do you think my idea of controlling all components via I2C bus is a 
> good idea? I want to go for the easiest and most versatile approach.
>
> 3. Are there anywhere existing sockets for IN-14 / IN-19 tubes? Or will I 
> have to solder to tubes to whatever components I select?
>
>  
>
> Thanks a lot for your help!
>

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Re: [neonixie-l] Re: Raspberry PI controlled Nixie display

['Ian Vine' via neonixie-l]

Not sure if we are getting wires crossed. The $102 price was for the Rpi hat to 
arduino shield adapter
IanV 

On Monday, 20 March 2017, 17:01, Tomasz Kowalczyk  
wrote:
 

 Yeah, but this is costly due to custom transformer used. I'd prefer a 12V 
supply and cheap NE555 converter or 5V + voltage doublers, as this is just 
cheaper than those 'ready to use' modules from ebay. On USB you are heavily 
limited with current anyway, so the clock has to be multiplexed or driven with 
<100% duty cycle. And I see no other point in using 5V power supply than making 
USB powered clock. USB 2.0 standard gives 500mA, which will be not enough to 
really use that converter fully :) Of course, cell phone chargers provide more 
current, but I think that if a clock is designed to have USB type supply, it 
should be possible to drive directly from a PC.The only reason I see for going 
with transformer converters is making a battery powered clock. But then I'd 
recommend using flash lamp cap charging transformers - generally very small and 
made exactly for converting battery voltages to high voltages.
W dniu poniedziałek, 20 marca 2017 16:42:49 UTC+1 użytkownik Alic napisał:
The eBay seller vfdclock also sells many different 5V to 170V or higher 
supplies (his eBay store is closed for a few days right now) 
:http://www.ebay.com/itm/ 131846790948?_trksid=p2060353. 
m1438.l2649=STRK% 3AMEBIDX%3AIThttp://www.ebay.com/sch/ 
vfdclock/m.html?_nkw=&_armrs= 1&_ipg=&_from=
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[neonixie-l] Re: Raspberry PI controlled Nixie display

[gregebert]

I chose the RasPi zero-W (the newest Pi, for $10 US) because it has 
built-in WiFi to do periodic time-sync, and it will allow me to update my 
clock software remotely, rather than taking the clock apart each time to 
update FPGA code.

My concern is the limited GPIO speed of the Pi, so I will have the Pi drive 
an FPGA, which in-turn drives the 7971 boards.
For now, the FPGA is strictly for remapping ASCII character data into 
segment info, then serializing. If I see other issues, such as "wobbly" 
data on the seconds, I may load-up more work on the FPGA.

Since I literally just taped-out my board last night, it's going to be 
several weeks before I have any idea how the Pi performs. Though I have 
another Pi for my 3D printer, I've never done any GPIO experimenting with 
it. 

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Tomasz Kowalczyk]

Yeah, but this is costly due to custom transformer used. I'd prefer a 12V 
supply and cheap NE555 converter or 5V + voltage doublers, as this is just 
cheaper than those 'ready to use' modules from ebay. On USB you are heavily 
limited with current anyway, so the clock has to be multiplexed or driven 
with <100% duty cycle. And I see no other point in using 5V power supply 
than making USB powered clock. USB 2.0 standard gives 500mA, which will be 
not enough to really use that converter fully :) Of course, cell phone 
chargers provide more current, but I think that if a clock is designed to 
have USB type supply, it should be possible to drive directly from a PC.
The only reason I see for going with transformer converters is making a 
battery powered clock. But then I'd recommend using flash lamp cap charging 
transformers - generally very small and made exactly for converting battery 
voltages to high voltages.

W dniu poniedziałek, 20 marca 2017 16:42:49 UTC+1 użytkownik Alic napisał:
>
> The eBay seller vfdclock also sells many different 5V to 170V or higher 
> supplies (his eBay store is closed for a few days right now) :
>
>
> http://www.ebay.com/itm/131846790948?_trksid=p2060353.m1438.l2649=STRK%3AMEBIDX%3AIT
>
> http://www.ebay.com/sch/vfdclock/m.html?_nkw=&_armrs=1&_ipg=&_from=
>
>

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Alic]

The eBay seller vfdclock also sells many different 5V to 170V or higher 
supplies (his eBay store is closed for a few days right now) :

http://www.ebay.com/itm/131846790948?_trksid=p2060353.m1438.l2649=STRK%3AMEBIDX%3AIT

http://www.ebay.com/sch/vfdclock/m.html?_nkw=&_armrs=1&_ipg=&_from=

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Alic]

Tomasz,
Tayloredge offers a HV power supply which gives up to 23mA @ 180V for a 5V 
input :
http://www.tayloredge.com

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Nick]

I wonder just wondering, if anyone has made a RPi hat that adapts to an 
Arduino header so that you could use an RPi with any (well, most) Arduino 
shield as there are 1000's of Arduino shields and only a few 100 (maybe) 
RPi hats...

Just a thought...

RATS! Someone else thought of it first - 
https://www.amazon.com/Raspberry-Arduino-Shields-Connection-Bridge/dp/B00F4S13FE
 

Nick

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[neonixie-l] Re: Raspberry PI controlled Nixie display

[Tomasz Kowalczyk]

Unfortunately there aren't any original IN-14 sockets. But there are good 
news: you can easily buy IN-14 to 2,54mm adapter from OSH park. I don't 
know if there is any existing project like this, but for me it is really 
short work and I could make gerber files for such PCB*. OSH makes three 
PCBs in one order, so you'd have to buy exactly 2 sets. PCBs would be dirt 
cheap - probably about 5$ for all 6 PCBs. So if you won't find them in OSH 
park database, just e-mail me.
I don't have any experience with Raspberry PI, but looking at its price I 
suggest considering any microcontroller family - in a Nixie Clock project 
you need mostly I/Os and timekeeping accuracy. Unless you are going for IoT 
project, RPI is going to be expensive and most of its calculating power 
won't be ever used.
There are possibilites to extend I/Os by I2C bus, for example with MCP23008 
(http://embedded-lab.com/blog/expanding-the-number-of-io-lines-using-microchip-mcp23008/).
 
You could use four of them, three controlling two 74141 drivers and one 
controlling 6x optoisolators (TLP627)**. This way you would be able to do 
ALL nixie controlling via I2c, but it would require many chips, fortunately 
all avaible in DIP packages. I have never personally used any I/O expander, 
so all what I wrote is a concept, not a tested idea.
If all of your sensors and RTC module (if you are planning to use 4 tubes 
as a clock, too) use I2C, then you could end up with a project using only 
those I/Os of your RPI :) I personally prefer using as many I/Os as I can.
If you want RGB lightning, I'm sure there are I2C chips capable of 
controlling them by current sinking. 
To change brightness of nixies you should "PWM" them. This is the best 
method of dimming nixies - changing HV supply voltage will eventually lead 
to undercurrenting tubes, and in that state they do not light a full digit. 
It is easiest to apply when multiplexing the display, as you need some dead 
time to avoid ghosting - so to change brightness you just make the dead 
time longer.
For a power supply I would recommend some dual voltage wall wart - 3A for 
RPI + 12,5mA x6 for 74141s + other modules... you will quickly require high 
current on 5V line, and to get HV from a switching supply, you will require 
at least 9V (12V preferably). If you won't find a 5V4A + 12V1A wall wart, 
then you probably have to either get a transformer and wire it to your 
liking or make a two-stage boost converter to make 180V out of 5V***.
I recommend making a HV PSU basing on NE555 with 12V supply - I made my 
unit for nixie testing and it was tested for 200V 40mA, reaching 83% 
efficiency (could be better if I used bigger resistors for feedback). 

*in fact, I already made such adapter a week ago as a part of bigger board, 
which had some unused space, but I deleted it and made a LC-531 adapter, 
because I lost an auction for IN-14s.
**all my 74141 which I tested didn't allow to turn a nixie off by sending a 
value bigger than 9 to it, there was a slight glow around all digits. So to 
be 100% sure that a nixie is turned off, you might use either a transistor 
anode switch or use a transoptor (optoisolator).
***there are possiblities to get 200V out of 5V, but they aren't easy or 
they provide little current - first one is a switching PSU with a pulse 
transformer, the other one is making a boost converter to ~60V and use a 
series of voltage doublers. I find the second one a viable choice only if 
you want to make a multiplexed clock powered from USB.

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