Re: [neonixie-l] resistance of filament warm vs cold
PV-electronics? Yeah I recommended his kits to many people. He now has a very cheap IN-12 kit by the way. But 20 ohms should be correct right? Because then I'll just stick two strings of -22ohm resistors in series- in parallel. I hope it is clear what I mean -- 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/f4964ea0-09d6-4b32-8c72-c85fc75e42a9%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
I think I'm going to warm up the soldering iron and stick some tubes in that protoboard (well do that three times) Op zondag 8 december 2013 11:05:08 UTC+1 schreef AlexTsekenis: Yes and yes. You need the arrangement you described if using standard 1/4 W resistors. You do not need a soft start circuit. Alex On Sunday, December 8, 2013 9:49:35 AM UTC, Gideon Wackers wrote: PV-electronics? Yeah I recommended his kits to many people. He now has a very cheap IN-12 kit by the way. But 20 ohms should be correct right? Because then I'll just stick two strings of -22ohm resistors in series- in parallel. I hope it is clear what I mean -- 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/8e879a54-e055-4904-9583-334123c769bd%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: Cutoff day Re: Shameless Plug, and Contest/Giveaway for NL5440As
I am not going to participate in a contest like this because I think there are members who deserve them a lot more than I do. It is nice to see someone doing something nice to a (very helpful) community like this. -- 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/8b2eefca-8125-4724-8297-474d5982160b%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: resistance of filament warm vs cold
Well the first board is filled with tubes, and my head is filled with headache from peering at the board.. The enameled wire was very hard to solder even after burning off the enamel layer. Although I do not dare to show the abomination that I call soldering the tubes are all connected. Don't worry I know how to solder, but the enamel wire was giving me a very hard time. The nice thing about the enamel wire was that it was easy to go through the forest of component legs. I'm off to bed. -- 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/811b0e78-c8ce-4982-8a0e-f1ba11b3bb33%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
O, so 20 ohms, well I have 10, 1 watt, 10 ohm resistors for three clocks so I'll make two extra pairs with some funky arrangement of 10 ohm, 22 ohm, and 47 ohm 1/4watt resistors. I only need 0,2W but, well I don't trust things being pushed to their limits. thanks for catching my silly mistake before I blow tubes. And about the tube not lighting up... Let me guess, the pins are counted from the bottom view and not top view. I think I hooked up two segments. When I was doing it I was already like; hmm why doesn't it look like those wires are going to the grid? sleep deprivation, it's a thing I believe :) -- 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/25ba7861-9f0d-450b-b2b2-443fe86bd282%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
Yeah 9/10 times when a light bulb breaks it goes when you turn it on. I do have a theory about them blowing in the early morning or late at night with an extra loud *POP* to just scare people. Op zaterdag 7 december 2013 02:56:24 UTC+1 schreef charles: On 13-12-06 06:06 AM, Gideon Wackers wrote: -filament resistance differs because it is cold Filament resistance is different when cold, which is why Incandescent Light bulbs generally fail at turn on if they are going to fail. -- Charles MacDonald Stittsville Ontario cm...@zeusprune.ca javascript: Just Beyond the Fringe http://Charles.MacDonald.org/tubes No Microsoft Products were used in sending this e-mail. -- 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/2b77b17c-da51-4218-ab0c-99ab1861f355%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
Well I'll keep an eye on the discussion about the filament resistor(s) to see what the final opinion is. In the mean time I discovered that tube pins are labeled from the bottom... and got my first fluorescent light (bright as hell even at 17,5 volt) http://i.imgur.com/RZjMkUf.jpg sorry for the messy picture but holding wires to three batteries and operating the camera at the same time is hard to do. -- 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/67f507d7-0f52-4905-b199-70bc8042c531%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] resistance of filament warm vs cold
I just measured the filament resistance of a IV-11 tube, according to my multimeter that is roughly 5-5,5 ohm (assuming it measures perfectly at such a low resistance). But I calculated something different; I'm going to wire the filaments of two tubes in series and feed them 5 volt though a resistor. So I used the voltage/resistor divider formula. to calculate the resistor needed for a 2 volt drop (tubes want 2*1,5V) and that is 10 ohms, going back to the voltage divider that gives ma a resistance of 15 ohms for both tubes and 7,5 ohms for each filament. Close you might say but still a 50% difference. Options: -my multimeter sucks -filament resistance differs because it is cold -both options -my calculations are wrong Well while I wait for an answer I'm going to build a little jig with lego so my tubes will be aligned perfectly straight :) -- 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/4e980192-1b38-42f2-b092-9e62298f2ea3%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
http://www.tube-tester.com/sites/nixie/dat_arch/IV-11_2.pdf IV-11 tubes use 1,5 volt for the filaments according to the datasheets I found Op vrijdag 6 december 2013 12:16:01 UTC+1 schreef Spencer: I used this as a reference for mine. If I remember right, it's around 1.15volts for the filament and 100mA. So with 5v power and 2 in series, 27ohm resistor though you want 2 watts. http://led.linear1.org/led.wiz Sent from my iPhone On Dec 6, 2013, at 5:06 AM, Gideon Wackers gideon@student.uhasselt.bejavascript: wrote: I just measured the filament resistance of a IV-11 tube, according to my multimeter that is roughly 5-5,5 ohm (assuming it measures perfectly at such a low resistance). But I calculated something different; I'm going to wire the filaments of two tubes in series and feed them 5 volt though a resistor. So I used the voltage/resistor divider formula. to calculate the resistor needed for a 2 volt drop (tubes want 2*1,5V) and that is 10 ohms, going back to the voltage divider that gives ma a resistance of 15 ohms for both tubes and 7,5 ohms for each filament. Close you might say but still a 50% difference. Options: -my multimeter sucks -filament resistance differs because it is cold -both options -my calculations are wrong Well while I wait for an answer I'm going to build a little jig with lego so my tubes will be aligned perfectly straight :) -- 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/4e980192-1b38-42f2-b092-9e62298f2ea3%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/eac38129-f17e-4bbc-b32d-96a6371c15a8%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
I just tried it carefully with a 1,5 volt battery, the filaments do not light up (good thing). but I could not get a segment to light up I only had two 9 volt batteries and that gave me 17,5 volt which is not enough. Btw I did notice that when I hooked up the 1,5 volt battery or took it away that the filaments made very soft *ting* sound. -- 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/79d9649e-48ab-4e65-be11-d36fd1307ba7%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
http://www.tubeclockdb.com/vfd-tubes/100-simple-vfd-tester.html this is what I did But I'll try it again tomorrow, maybe one of the connections was bad because I had to hold the wires against the batteries at 4 different points :P Op vrijdag 6 december 2013 16:11:42 UTC+1 schreef Spencer: Did you hook the 17.5v to the grid and segment you wanted to light up? It should be a faint glow Sent from my iPhone On Dec 6, 2013, at 5:41 AM, Gideon Wackers gideon@student.uhasselt.bejavascript: wrote: I just tried it carefully with a 1,5 volt battery, the filaments do not light up (good thing). but I could not get a segment to light up I only had two 9 volt batteries and that gave me 17,5 volt which is not enough. Btw I did notice that when I hooked up the 1,5 volt battery or took it away that the filaments made very soft *ting* sound. -- 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/79d9649e-48ab-4e65-be11-d36fd1307ba7%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/e30376fe-3ac7-4d88-b6e7-73a16b2644e4%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] resistance of filament warm vs cold
Yeah I could not see them glow in a dim lit room so :) Op vrijdag 6 december 2013 16:08:03 UTC+1 schreef nixiebunny: I don't know much about that tube. However, I do know: 1. Filaments have lower resistance when cold. 2. VFD filaments should not get bright enough to see clearly. A tiny glow in a dark room, maybe. On 12/6/13 4:06 AM, Gideon Wackers wrote: I just measured the filament resistance of a IV-11 tube, according to my multimeter that is roughly 5-5,5 ohm (assuming it measures perfectly at such a low resistance). But I calculated something different; I'm going to wire the filaments of two tubes in series and feed them 5 volt though a resistor. So I used the voltage/resistor divider formula. to calculate the resistor needed for a 2 volt drop (tubes want 2*1,5V) and that is 10 ohms, going back to the voltage divider that gives ma a resistance of 15 ohms for both tubes and 7,5 ohms for each filament. Close you might say but still a 50% difference. Options: -my multimeter sucks -filament resistance differs because it is cold -both options -my calculations are wrong Well while I wait for an answer I'm going to build a little jig with lego so my tubes will be aligned perfectly straight :) -- 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/4e980192-1b38-42f2-b092-9e62298f2ea3%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- 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/c9d21b10-4df8-44bf-a8be-c74d39a4587c%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] How to get IV-11 VFD tubes properly aligned on protoboard
I received my IV-11 tubes today and I was trying to put them on a board, a prototyping board. The best way to insert them (that I found) was the one in the attachment. But I noticed that the tubes would be ever so slightly tilted, aprox 1-2 mm over the whole tube. Does anyone have a better way to place them? I have added an empty piece of protoboard next to my best try in case someone wants to show his/her idea. My alternative plan is to just bend the wires a little but I don't want to stress the connection to the glass feedthrough (?) too much. For those who followed my previous thread(s) currently I am only waiting for the PLCC to dip sockets and DC-DC convertors, the rest is here. And a friend is helping me with the arduino code. :) -- 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/a2662833-d7fa-4a72-9f02-c3b9c9ab5f59%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. attachment: IV-11.png
Re: [neonixie-l] How to get IV-11 VFD tubes properly aligned on protoboard
Ok I'll see wether i can place them a bit higher as I was pushing them almost against the pcb. -- 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/7cc4f94c-f120-4d80-bba4-ad77f5334f1b%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: IV-11 VFD clock, some questions
Yes it is very nice but also very smart. People will like you a lot more because of it and maybe that student that gets 10 dollar in samples today later orders shiploads of IC's from your company because he now designs equipment and remembers how nice those samples were. But now I am looking for some arduino code to drive the MAX6921, code seems sarce and the icetubeclock uses an older software version I believe. Op woensdag 20 november 2013 20:58:37 UTC+1 schreef Adam Jacobs: Congratulations! I've always been a big fan of Maxim's sampling policy. I've even abused it (obviously, since I have a drawer-full of their stuff). The only times that I've had them object to any part of a sample request, I was requesting DIP samples. Anything PLCC or surface mount, they're ultra crazy generous. My theory (and the theory of co-workers here) is that Maxim samples like they do because they know that these engineers who have worked with their parts on side-projects and hobbies will select them for big projects at work as well. FYI, the MAX6921 is also the driver IC that Limor Fried is using in her VFD clock kit. -Adam On 11/20/2013 11:07 AM, Gideon Wackers wrote: Might be interesting for others: there are two versions of the XL6009 step up converter on ebay, one that goes to 35 volt, and another that reaches 45 volt. Example of a 45 volt type: http://www.ebay.com/itm/2pcs-XL6009-DC-DC-Adjustable-Boost-Step-up-Power-Supply-Module-6A-Output-6V-45V-/171127883167?pt=LH_DefaultDomain_0hash=item27d804459f It looks like Maxim does support starving students, I'll order the transistors anyway but I will probably work with the MAX6921 now. -- 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/a3edfa81-0660-4381-8ab0-b7085a7b37c9%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Arduino and MAX6921
The law starts to apply when someone dies by your electronic contraption ;) Op donderdag 21 november 2013 23:34:24 UTC+1 schreef Adam Jacobs: Ah-ha! Good deal. I was assuming that your were in school studying electronics or microcontrollers, since you were posting to the group from a university address. :) Well, more and more, I think that electronics software are extremely useful skill sets for anyone. Well, Electronics, Software Law. But Law is outside the scope of discussion. :) We have an employee here at work that joined as an intern (on a lark) during a break from her doctoral studies in biochemistry. She liked it so much that she stayed, changed her pending doctorate into an existing masters and joined the company full-time as a software engineer. -Adam On 11/21/2013 1:18 PM, Gideon Wackers wrote: Lets put it like this, the only programming I ever do is a bit of LabVIEW. I'm doing a master in Bioelectronics and Nanotechnology but although it says electronics in the name, there is not too much classic electronic stuff. It mainly involves biosensor applications and cell membrane potentials which is a completely different branch of electronics. That your code is not in the arduino language but Atmel already explains a bit of my confusion. I'm going to take another look at it and maybe a friend of mine who is a lot better at written programming languages can help me a bit. Op donderdag 21 november 2013 21:47:33 UTC+1 schreef Adam Jacobs: Hi Gideon, What are you studying at university? We're starting to get to the point where you should be able to start figuring it out. Definitely shouldn't look like voodoo... Start with the Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX6921-MAX6931.pdfhttp://www.google.com/url?q=http%3A%2F%2Fdatasheets.maximintegrated.com%2Fen%2Fds%2FMAX6921-MAX6931.pdfamp;sa=Damp;sntz=1amp;usg=AFQjCNGRtl_SODtV_fkIirNXSTrOBC7YrQ The datasheet tells us that the part is SPI (Serial interface), which means it is much easier to talk to than a I2C part. I'm not going to be able to help you with arduino, I've never used one. I always just program the Atmel microcontroller directly and use the part directly without the arduino bootloader/sketches business. To each their own. One of the huge advantages of the Arduino, though, is supposed to be the availability of community libraries to support these parts. I would maybe look a little harder or consider switching components to something that already has a community library written for it. I linked you the code/schematic to my VFD clock which uses a max6921. It's not arduino sketch, it is atmel microcontroller C code. I think that you should be able to figure it out. Worst case, the arduino sketches are guaranteed to include support for sending a command via SPI. http://elbastl.sweb.cz/6-digit-VFD.ziphttp://www.google.com/url?q=http%3A%2F%2Felbastl.sweb.cz%2F6-digit-VFD.zipamp;sa=Damp;sntz=1amp;usg=AFQjCNHVYn6ZtoXr__UZsJOdqXWRVdKNrQ The part of the code that you should be interested in is the part that I cribbed from Limor's IceClock. Specifically, the spi_xfer(), vfd_send(), setdisplay(). Setdisplay will definitely need to be modified to suit your clock, but spi_xfer and vfd_send are the 'voodoo' that you are trying to understand. Look at the schematic in that file to see how SPI parts are electrically connected to the microcontroller. -Adam On 11/21/2013 12:11 PM, Gideon Wackers wrote: Well after all the great help with the hardware part of the arduino I have been looking at the code for my clock. For clarity I thought it would be better to open a new thread just about the software. What I want to make is a four digit clock with IV-11 VFD's that simply starts at 12:00 and starts running, no fancy menus or anything. Time will be set with two buttons; Button A increases the hours by 1, Button B increaes the minutes by 1. Pretty simply one would say but after looking at various other peoples code such as: https://github.com/8163jb/VFD/blob/master/MAX6921_With_RTC/MAX6921_With_RTC.inohttps://www.google.com/url?q=https%3A%2F%2Fgithub.com%2F8163jb%2FVFD%2Fblob%2Fmaster%2FMAX6921_With_RTC%2FMAX6921_With_RTC.inoamp;sa=Damp;sntz=1amp;usg=AFQjCNGUc_A3Csxrdw-xB8zSzj79qQB2ZQ http://www.vonnieda.org/tc18http://www.google.com/url?q=http%3A%2F%2Fwww.vonnieda.org%2Ftc18amp;sa=Damp;sntz=1amp;usg=AFQjCNE-DUrHyqMq3tlB8WUhgFiRlEIzQQ http://learn.adafruit.com/ice-tube-clock-kit/http://www.google.com/url?q=http%3A%2F%2Flearn.adafruit.com%2Fice-tube-clock-kit%2Famp;sa=Damp;sntz=1amp;usg=AFQjCNHf_jtyHS3FKe9_W092hhXkOjN9aA I am completely lost. I do understand how to create the digit pattern in an effective way such as shown here: http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.htmlhttp://www.google.com/url?q=http%3A%2F%2Fwww.hacktronics.com%2FTutorials%2Farduino-and-7-segment-led.htmlamp;sa
Re: [neonixie-l] Re: Arduino and MAX6921
Yeah this project is also a bit of a learning project, but time is starting to become scarce so I'll have to have some results (plus code is not exactly my strong point) and really learn later on. Anyway, my to do list: -Find out where time setting is done, and/or add it to my code -fix the small bugs -find out whether this is going to work -- 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/04711d2c-068d-4535-be09-36e9e60778fe%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: Arduino and MAX6921
Yeah as I thought, I'll have to add something to the code for setting the time. And well... Time is short (Christmas), interest is surely present. Two worst case scenarios: it is not ready and they receive a IOU a clock coupon instead of a clock *or *it never gets finished because my programming skills kinda suck. *doom scenario: things catch fire :P* Op vrijdag 22 november 2013 00:02:34 UTC+1 schreef Adam Jacobs: Time-setting as well as time-getting and displaying will need to be done on the Microcontroller. The RTC relies on receiving an I2C message with the time to set; it doesn't have any mechanism for connecting buttons or such directly. 'find out whether this is going to work' is probably something that depends entirely on the amount of interest time you have. :) On 11/21/2013 2:59 PM, Gideon Wackers wrote: Yeah this project is also a bit of a learning project, but time is starting to become scarce so I'll have to have some results (plus code is not exactly my strong point) and really learn later on. Anyway, my to do list: -Find out where time setting is done, and/or add it to my code -fix the small bugs -find out whether this is going to work -- 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/04711d2c-068d-4535-be09-36e9e60778fe%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/18bed0ef-bbe1-486c-8c82-350299d22b56%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: Arduino and MAX6921
Maybe I should not be doing this kind of thing late in the evening I just noticed the attachment in this thread http://forum.arduino.cc/index.php?topic=159775.0 which gave me a complete piece of code. This made things a lot clearer and I have started stripping the code of things I do not need to make things easier. I will also add a RTC because for what they cost it seems like they make things a lot easier. There are still some tiny errors in this piece of code that need fixing but I think that the raw basis is there. -- 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/81ab3833-dffd-430c-b4f3-5a204eb28529%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. arduino_6921.ino Description: Binary data
Re: [neonixie-l] Arduino and MAX6921
Lets put it like this, the only programming I ever do is a bit of LabVIEW. I'm doing a master in Bioelectronics and Nanotechnology but although it says electronics in the name, there is not too much classic electronic stuff. It mainly involves biosensor applications and cell membrane potentials which is a completely different branch of electronics. That your code is not in the arduino language but Atmel already explains a bit of my confusion. I'm going to take another look at it and maybe a friend of mine who is a lot better at written programming languages can help me a bit. Op donderdag 21 november 2013 21:47:33 UTC+1 schreef Adam Jacobs: Hi Gideon, What are you studying at university? We're starting to get to the point where you should be able to start figuring it out. Definitely shouldn't look like voodoo... Start with the Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX6921-MAX6931.pdfhttp://www.google.com/url?q=http%3A%2F%2Fdatasheets.maximintegrated.com%2Fen%2Fds%2FMAX6921-MAX6931.pdfsa=Dsntz=1usg=AFQjCNGRtl_SODtV_fkIirNXSTrOBC7YrQ The datasheet tells us that the part is SPI (Serial interface), which means it is much easier to talk to than a I2C part. I'm not going to be able to help you with arduino, I've never used one. I always just program the Atmel microcontroller directly and use the part directly without the arduino bootloader/sketches business. To each their own. One of the huge advantages of the Arduino, though, is supposed to be the availability of community libraries to support these parts. I would maybe look a little harder or consider switching components to something that already has a community library written for it. I linked you the code/schematic to my VFD clock which uses a max6921. It's not arduino sketch, it is atmel microcontroller C code. I think that you should be able to figure it out. Worst case, the arduino sketches are guaranteed to include support for sending a command via SPI. http://elbastl.sweb.cz/6-digit-VFD.ziphttp://www.google.com/url?q=http%3A%2F%2Felbastl.sweb.cz%2F6-digit-VFD.zipsa=Dsntz=1usg=AFQjCNHVYn6ZtoXr__UZsJOdqXWRVdKNrQ The part of the code that you should be interested in is the part that I cribbed from Limor's IceClock. Specifically, the spi_xfer(), vfd_send(), setdisplay(). Setdisplay will definitely need to be modified to suit your clock, but spi_xfer and vfd_send are the 'voodoo' that you are trying to understand. Look at the schematic in that file to see how SPI parts are electrically connected to the microcontroller. -Adam On 11/21/2013 12:11 PM, Gideon Wackers wrote: Well after all the great help with the hardware part of the arduino I have been looking at the code for my clock. For clarity I thought it would be better to open a new thread just about the software. What I want to make is a four digit clock with IV-11 VFD's that simply starts at 12:00 and starts running, no fancy menus or anything. Time will be set with two buttons; Button A increases the hours by 1, Button B increaes the minutes by 1. Pretty simply one would say but after looking at various other peoples code such as: https://github.com/8163jb/VFD/blob/master/MAX6921_With_RTC/MAX6921_With_RTC.inohttps://www.google.com/url?q=https%3A%2F%2Fgithub.com%2F8163jb%2FVFD%2Fblob%2Fmaster%2FMAX6921_With_RTC%2FMAX6921_With_RTC.inosa=Dsntz=1usg=AFQjCNGUc_A3Csxrdw-xB8zSzj79qQB2ZQ http://www.vonnieda.org/tc18http://www.google.com/url?q=http%3A%2F%2Fwww.vonnieda.org%2Ftc18sa=Dsntz=1usg=AFQjCNE-DUrHyqMq3tlB8WUhgFiRlEIzQQ http://learn.adafruit.com/ice-tube-clock-kit/http://www.google.com/url?q=http%3A%2F%2Flearn.adafruit.com%2Fice-tube-clock-kit%2Fsa=Dsntz=1usg=AFQjCNHf_jtyHS3FKe9_W092hhXkOjN9aA I am completely lost. I do understand how to create the digit pattern in an effective way such as shown here: http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.htmlhttp://www.google.com/url?q=http%3A%2F%2Fwww.hacktronics.com%2FTutorials%2Farduino-and-7-segment-led.htmlsa=Dsntz=1usg=AFQjCNFsJItE19S7zIuGgjCoUZWhZfVBEw But when I see other peoples examples, driving the MAX6921 looks like voodoo to me. Can someone give me a hint/tip/example on how to get going with this project? -- 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/a3465b27-72b0-45b2-b897-e36e474609e1%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
[neonixie-l] Arduino and MAX6921
Well after all the great help with the hardware part of the arduino I have been looking at the code for my clock. For clarity I thought it would be better to open a new thread just about the software. What I want to make is a four digit clock with IV-11 VFD's that simply starts at 12:00 and starts running, no fancy menus or anything. Time will be set with two buttons; Button A increases the hours by 1, Button B increaes the minutes by 1. Pretty simply one would say but after looking at various other peoples code such as: https://github.com/8163jb/VFD/blob/master/MAX6921_With_RTC/MAX6921_With_RTC.ino http://www.vonnieda.org/tc18 http://learn.adafruit.com/ice-tube-clock-kit/ I am completely lost. I do understand how to create the digit pattern in an effective way such as shown here: http://www.hacktronics.com/Tutorials/arduino-and-7-segment-led.html But when I see other peoples examples, driving the MAX6921 looks like voodoo to me. Can someone give me a hint/tip/example on how to get going with this project? -- 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/a3465b27-72b0-45b2-b897-e36e474609e1%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IV-11 VFD clock, some questions
Can someone tell me how to tweak and/or calculate the value of R6? I would like to order my parts this evening, so it would be nice to know what extra parts to order in case something needs adjustment. I will show the results including CNC milled enclosures (a friend can make them very cheap :D ) -- 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/958b1c9c-2556-4906-8c20-82bc6f14e676%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IV-11 VFD clock, some questions
Sadly my sample request for some HV5812 was denied, but I will go for the transistor drivers (2n3904 + MPSA92) like mentioned a few posts ago. -- 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/1f106b6e-3432-4426-b01d-5ee64a3a0571%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IV-11 VFD clock, some questions
I could give them sunglasses with the clock :) Might be interesting for others: there are two versions of the XL6009 step up converter on ebay, one that goes to 35 volt, and another that reaches 45 volt. Example of a 45 volt type: http://www.ebay.com/itm/2pcs-XL6009-DC-DC-Adjustable-Boost-Step-up-Power-Supply-Module-6A-Output-6V-45V-/171127883167?pt=LH_DefaultDomain_0hash=item27d804459f It looks like Maxim does support starving students, I'll order the transistors anyway but I will probably work with the MAX6921 now. -- 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/ae596874-f919-4e34-86a5-6fa51725aa15%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] IV-11 VFD clock, some questions
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 supply with a 7806 and wires them in series, AC will be generated by four bs170 mosfets. Do I still need a filament resistor if I match my voltages this exact? Suggestions are welcome, my PCB can be roughly 9 by 5 cm so maybe there are other (cheap) alternatives to using resistors as drivers? I first got this idea because everything had to be stuffed onto a smaller pcb so maybe now that I have more space I can now use some IC's instead? -- 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/62997dbb-f1ac-4b11-8e24-42f3eec74ad6%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IV-11 VFD clock, some questions
Thank you for your reply, sadly the HV5812 is SMD and I am going to do this on simple strip/hole PCBs. But you are using two tubes in series on 5 volt so that leaves about 2 volts for the resistor. My plan is to hook them all up in series (4 tubes) so I require 6 volts which can be delivered by the 7806. The result is (at least in my head) that I do not even need a filament resistor because I require no voltage drop. But I think that I am going to drive them at a lower than 60 volt supply because again someone mentions that 30-40 volt is bright enough. I think I will use a simple DCDC convertor off ebay to make 35 volt ( http://www.ebay.com/itm/XL6009-DC-DC-Adjustable-Step-up-boost-Power-Converter-Module-Replace-LM2577-/130987148386?pt=LH_DefaultDomain_0hash=item1e7f714462 ) just for simplicity because I am not that much of a software guy. Maybe this allows for easier driving methods such as a transistor array like the uln2803? I also hear a lot of different opinions on DC or AC filaments, You are using DC (but only two tubes in series), do you notice any gradient? -- 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/9fd4e8e1-8c62-47ad-8807-d2bca4078b90%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: IV-11 VFD clock, some questions
Yeah but that would cost me 50 dollar in shipping :( (to the netherlands). What about my driver circuit on soms transistor array, driving 35 volt should not be that much of a problem? Op dinsdag 19 november 2013 15:56:58 UTC+1 schreef William Lee: Hi Gideon- I believe the HV5812 is still available in a PDIP package: http://www.onlinecomponents.com/supertex-hv5812p.html?p=12648889 On Tue, Nov 19, 2013 at 9:42 AM, Gideon Wackers gideon@student.uhasselt.be javascript: wrote: HV5812 -- 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/3dc883d5-72da-421e-89cc-9b58ccdddcef%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IV-11 VFD clock, some questions
Slight update: I just found a local retailler (mouser) which also sells them, but 20 euro in shipping costs... That is more than what a dozen of tubes is going to cost me. -- 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/48569648-c91b-4a55-96b4-f52894460efb%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] IV-11 VFD clock, some questions
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] Re: IV-11 VFD clock, some questions
Okay else I will just take one of those step down converters off ebay http://www.ebay.com/itm/5-pcs-DC-DC-LM2596-Power-Supply-Step-Down-Adjustable-Converter-Module1-3V-35V-/130984321712?pt=LH_DefaultDomain_0hash=item1e7f4622b0 For that price I can't go messing around with DC-DC converters myself and I can just match the voltage to my tubes. Do any of you use some sort of protection circuit for the filaments? Op dinsdag 19 november 2013 20:34:13 UTC+1 schreef Spencer: Only on longer tubes will you truly notice gradient so you might see it if you do 4 or 6 in a series. Sent from my iPhone On Nov 19, 2013, at 8:42 AM, Gideon Wackers gideon@student.uhasselt.be javascript: wrote: Thank you for your reply, sadly the HV5812 is SMD and I am going to do this on simple strip/hole PCBs. But you are using two tubes in series on 5 volt so that leaves about 2 volts for the resistor. My plan is to hook them all up in series (4 tubes) so I require 6 volts which can be delivered by the 7806. The result is (at least in my head) that I do not even need a filament resistor because I require no voltage drop. But I think that I am going to drive them at a lower than 60 volt supply because again someone mentions that 30-40 volt is bright enough. I think I will use a simple DCDC convertor off ebay to make 35 volt ( http://www.ebay.com/itm/XL6009-DC-DC-Adjustable-Step-up-boost-Power-Converter-Module-Replace-LM2577-/130987148386?pt=LH_DefaultDomain_0hash=item1e7f714462 ) just for simplicity because I am not that much of a software guy. Maybe this allows for easier driving methods such as a transistor array like the uln2803? I also hear a lot of different opinions on DC or AC filaments, You are using DC (but only two tubes in series), do you notice any gradient? -- 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/9fd4e8e1-8c62-47ad-8807-d2bca4078b90%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/1702c1ac-c89b-4245-8a72-4512fa4482b9%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[neonixie-l] Re: IN-37 ???
Yikes that is quite an amount of money for an odd tube, I do understand buying something because it is special but that sounds a bit over the top. -- 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/31731760-3780-4293-91a1-ab3893fa7a08%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: IV-11 VFD clock, some questions
Yeah I think I'll go for a Op dinsdag 19 november 2013 21:07:42 UTC+1 schreef jrehwin: Do any of you use some sort of protection circuit for the filaments? I just use a higher voltage supply and a series resistor. That way, the difference in current between a cold filament and a hot one is less, so the starting surge is minimized. It's less efficient than just driving the filaments at their rated voltage directly, but safer. Another approach is to use a current regulated supply instead of a voltage regulated supply - then you can skip the resistor. Note that if you're using a 7806 anyway, the efficiency is the same - it's a linear regulator, so the heat shows up in the regulator instead of the resistor. In this case, I'd either use a 7808 and a resistor (reducing the heat on the regulator and gaining some protection), or wiring it up as a current source: http://www.circuitstoday.com/fixed-positive-voltage-regulators As it happens, the 7806 does have the ability to limit current, so it won't give the cold filament more than 1.5A or so anyway, which helps a little (it's still more than 3x the rated current, however). - 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/79044f53-f6d6-4af7-a47d-9b8ed249e146%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] Re: IV-11 VFD clock, some questions
Yeah I was just thinking of wiring two filaments in series and feeding them with a 7805, that means a 10 ohm 1 watt resistor. That way I'll have the best of both worlds; minimal gradient effect, easy DC and resistor protection So now I only have to figure out wether my two transistor driver is a good way to drive my IV-11 tubes :) A big thank you for all the help until now, I've only got my driver question remaining :) Op dinsdag 19 november 2013 21:15:05 UTC+1 schreef Gideon Wackers: Yeah I think I'll go for a Op dinsdag 19 november 2013 21:07:42 UTC+1 schreef jrehwin: Do any of you use some sort of protection circuit for the filaments? I just use a higher voltage supply and a series resistor. That way, the difference in current between a cold filament and a hot one is less, so the starting surge is minimized. It's less efficient than just driving the filaments at their rated voltage directly, but safer. Another approach is to use a current regulated supply instead of a voltage regulated supply - then you can skip the resistor. Note that if you're using a 7806 anyway, the efficiency is the same - it's a linear regulator, so the heat shows up in the regulator instead of the resistor. In this case, I'd either use a 7808 and a resistor (reducing the heat on the regulator and gaining some protection), or wiring it up as a current source: http://www.circuitstoday.com/fixed-positive-voltage-regulators As it happens, the 7806 does have the ability to limit current, so it won't give the cold filament more than 1.5A or so anyway, which helps a little (it's still more than 3x the rated current, however). - 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/eb0bc018-3996-4f47-afa0-da83b9a4eedf%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [neonixie-l] IV-11 VFD clock, some questions
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
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
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
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
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
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.
