Soviet era, gorgeous IN-34-1 bargraph display. - Page 1
Forum section: electronics / projects

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 06, 2019, 05:06:01 pm
content: Browsing thru Ebay, I've noticed lately some gorgeous, Soviet-era, gas discharge bargraph displays.Now, I am familiar with the more ubiquitous analog gas discharge bargraphs, like the IN-9 or IN-13, whereas a cathode current (more or less) linearly controls the length of the bargraph which lights up. But these bargraphs are digitally controlled, and therefore capable of higher precision. With some of them sporting 203 discrete elements, a very high precision bargraph display can be achieved. These come in different formats, but they all share a high voltage gas discharge, and sequential addressing of the elements.Unfortunately, the information available on the web is scarce and sometimes with errors. See some sample "instructions" and datasheets. There are no actual circuit examples which I can find.To make posts more readable, and avoid the dreaded TL;DR syndrome, I'll leave it right here. But from my studies I've been able to discern some basic operation modes from the scant information available.

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 06, 2019, 05:22:33 pm
content: For instance, the following paragraph:-The work principle is similar to a Dekatron:Dekatrons operate similarly to stepper motors, where a control cathode is pulsed, then the next adjacent control cathode, then the first one released, followed by the second one being released. Depending on which of the pair of control cathodes was energized first, that will be the duration of the count.So I believe that the scanning of individual elements would follow a similar pattern, but then I fail to understand how the cathode that has been counted to remains lit up, if the pulse is released like a Dekatron would....or perhaps that pin remains activated? I don't know.I have changed a previous attachment....in one of the the datasheets there are duplicate opins with an identical description "Cathode of third group" and thus I had added a little note on the bottom.....but after studying a little bit more, I am not sure and thus removed the note and left it with the original wording

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 06, 2019, 05:35:55 pm
content: Something that I believe have understood correctly, is the operation of the auxiliary anode and cathode. In linear bargraphs like the IN-13, the auxiliary cathode helps (as I understand it) to ensure that the main column is completely unlit in the absence of a signal or data. This assumption appears to be validated by the fact of the auxiliary cathode current being quite small.What I do not get is the paragraph ""..designed to display information in the form of a linear scale of 103 elements withthe release of each 5th element" Which is the 5th element?So far, this is what I've got. Brainstorming ideas or hints are welcome.

author: iMo
author_rank: Super Contributor
timestamp: August 06, 2019, 05:47:52 pm
content: There is 103 elements in total, with every 5th "displaced for better reading".

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 06, 2019, 07:43:13 pm
content: Imo,now that you mention it, it is so obvious..... I feelFollowing your description, would this perhaps mean that after the 5th element is reached, it will jump to the first element of the next stage? And one has to start the sequence enebling the first element?Before anyone asks: No, I still haven't purchased one of these yet. They are a bit pricey, and won't take the plunge purchasing one unless I feel that I halfway understand its basic operation.

author: FenTiger
author_rank: Regular Contributor
timestamp: August 06, 2019, 10:29:51 pm
content: http://users.rcn.com/ted.johnson/ssbar.htmsuggests this:Quote

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 07, 2019, 01:23:35 pm
content: FenTiger, thanks for the link.............this cleared many doubtsI believe that I've enough of a head start, such that I can order some devices and have a moderate chance of success.For the benefit of anyone with a passing interest on these devices, I will from time to time, report on my findings.For starters, I will focus on the IN-34-1, as it is moderately priced and appears to have the most documentation online. I color coded the different cathodes with the function description. This helps to visualize their function and clear some translation mistakes. For instance, there were a pair of "Cathode of the third group", but the magenta-colored one is actually the first cathode.I also include the device's pinout location.I am still puzzled by the sentence ".....with the release of the 5th element". I am not sure they are referring to the5th visual elementas indicated by Imo, but perhaps it means the release of the auxiliary cathode.(Cathode groups 1 thru 3, reset cathode, and auxilliary cathode making the 5th cathode element).I also believe that I've figured out the overload cathode function, which would should really mean "overflow" cathode.Sigh...it is a little hard to figure out things without the benefit of a timing diagram.

author: LaserSteve
author_rank: Super Contributor
timestamp: August 08, 2019, 02:35:01 pm
content: Google Burroughs and SELF SCAN or BAR GRAPH and or Panaplex...And ye shall be rewarded..See attached for a start, Soviet Devices will be similar or improved.1976 Technology, and beautifully simple.Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: August 08, 2019, 03:05:34 pm
content: See also this and related pages..http://ferretronix.com/tech/nixie/pdf/vishay_dale_bar_graph_designers_guide.pdfAnd this:http://dotdisplay.blogspot.com/2017/08/igt1-203-self-scan-bar-graph-display.htmlSteve

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 08, 2019, 04:38:07 pm
content: Thank you Steve, the pieces of the puzzle are finally falling together!.In addition to the valuable info you have provided, I found an app note from a Japanese supplier with a timing diagram (yesssss!), which clearly illustrates the interface operation chapter of the Vishay-Dale datasheet you provided. See page 2 of my attached file.The Vishay datasheet also includes a timing diagram, but it is cluttered and not immediately understandable.The Vishay datasheet also includes a discrete logic driving circuitry, nowadays, any simple microcontroller can do the job.With all the information, however scattered, I am now confident that I can successfully tackle this project, and not be left in the dark (He. he! see what I just did here?) with more electronic junk.Thanks everyone who helped me gather the info. This definitively will be my next project....after I complete the one I am working on.Discipline! I have to finish the previous one first, otherwise I will end up with a pair of unfinished projects. It is an addiction guys, you already know the feeling.

author: LaserSteve
author_rank: Super Contributor
timestamp: August 08, 2019, 05:49:24 pm
content: I just ordered one of the big Russian tubes. I do sound for my place of worship and the idea of having one of those instead of the short bar on the mixer LCD is intriguing. Especially for vocals. The Mitani timing diagram brought the "how" into short focus. I've used lab lasers that have the Borroughs analog bars in their remote control heads, I'll see if I have a schematic.Good Luck,Steve

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 09, 2019, 01:08:17 am
content: Steve;as a matter of fact, the website where I found the Mitani datasheet was one dedicated to professional audio.Posters there commented that with 100 or even 200 elements, these tubes would make exceptional VU meters.Which tube number did you order?

author: Datman
author_rank: Regular Contributor
timestamp: August 09, 2019, 07:50:49 am
content: Keep in mind that it is linear, i think. For a VUmeter you need, instead, a custom logarithmic scale, using complex electronics.You can do the same without complex electronics (and typical log amps thermal instability) using Arduino, a 16-bit converter and a LCD or OLED graphic displayhttps://www.google.com/search?q=arduino+graphic+vu+meterhttps://www.google.com/search?q=arduino+graphic+display+bargraph+vu+meter

author: xavier60
author_rank: Super Contributor
timestamp: August 09, 2019, 08:56:53 am
content: This application note has designs for filtered rectifiers that replicate the proper meter ballistics for VU or PPM.I used a PIC micro to do the log conversion using a lookup table and also multiplex LED bar graph displays.https://datasheet.octopart.com/LM3916N-1/NOPB-National-Semiconductor-datasheet-7551873.pdf

author: 001
author_rank: Super Contributor
timestamp: August 09, 2019, 02:58:18 pm
content: HiYou can also use analog fluorescent bargraph like EMM81It is only sort of magic eye tubeIt drivered directly from grid. No additional elements requiered

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 09, 2019, 04:45:46 pm
content: hmmmmmmmmmmm...........Googling EMM81 only returns results for the common magic eye EM81

author: 001
author_rank: Super Contributor
timestamp: August 09, 2019, 04:58:38 pm
content: Quote from: schmitt trigger on August 09, 2019, 04:45:46 pmtry russian analoghttp://tvr.vejas.lt/uploads/Zinynas/Lempos/Indikatoriai.pdf

author: edavid
author_rank: Super Contributor
timestamp: August 09, 2019, 04:59:57 pm
content: Quote from: schmitt trigger on August 09, 2019, 04:45:46 pmIt looks like the correct part number is EMM801.I think the EM800 is similar.Neither one can really compare to that beautiful IN-33.