hybridfree/eevblog-posts huggingface dataset:
KiCad drill file Error - Page 1
Forum section: electronics / general

author: donavan
author_rank: Contributor
timestamp: July 09, 2014, 01:56:16 pm
content: Hello,I try to create a drill file in Gerber format but it tells me translated "Coudnt create XXXX.drl" (Original: "Konnte Datei <C:GerbderData\XXX.drl> nicht erstellen.). Another board i created the Gerbers for today, he had no problems at all.What kind problems can cause this? The error message isnt realy helpful for the error search.Can he have problems with the drill sizes or maybe with the too precise positioning in KiCad?/Editok i deleted everything on the board and just placed a single Pin and it had the same error. When i created a completly new board it worked fine, so he doesnt seem to have a problem with the size of the drills.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 09, 2014, 09:35:13 pm
content: As a WAG, look at the directory where it's trying to create the file. Make sure it doesn't already exist. Verify it's a legal filename. Make sure you haven't filled up the disk. Check folder permissions. An error message (in any program) that says "Unable to create file xxxx" usually means just that -- it can'tcreatethe file. First port of call is to look at the file system for clues. Also, check the Event Viewer (in Control Panel -> Admin Tools) to see if it left a more verbose message there.

author: Neverther
author_rank: Regular Contributor
timestamp: July 10, 2014, 06:46:59 am
content: Or just try setting other output directory.If the message really says "C:GerbderData\XXX.drl" it is missing \ after C:.

author: donavan
author_rank: Contributor
timestamp: July 10, 2014, 08:17:01 am
content: thanks for the suggestions, i tried alot of different directories but apperently i never tried another harddrive...Yesterday i routed the complete board again and the drill file created fine throughout the process. Then today i open the project, made some tweaks and the same error again... after reading your comments i tried another hardrive and it worked again somehow... All drives are NTFS and have more then enough diskspace. Maybe somehow the directory was wrong, i chose the directory with the Browse button.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 10, 2014, 07:12:39 pm
content: A very common pattern is this: Works the first time, doesn't work subsequent times. Change output folder and it will again work the first time, and not after. That is usually due to one of the following:1) The program doesn't properly handle the condition of an existing file. Being that it's KiCAD, that's entirely possible.2) The file was opened in a mode that doesn't support overwrite. Again, basic programming error that is entirely likely at this stage of development.3) The directory permissions allow creating new files but not overwriting existing ones. That's all you. (Are you logged in as admin?)4) The program did something to the directory or file permissions that prevent further modifications. Possible, but not as likely.5) Some program on your computer (anti-virus, Gerber viewer, etc.) has the file open, locking it against write operations.
Can you ID the characters on these chips from a Datavue Spark? - Page 1
Forum section: electronics / general

author: option8
author_rank: Newbie
timestamp: July 10, 2014, 04:41:33 pm
content: Doing my own retro laptop teardown a while back, in order to clean and sell, I uncovered these little cartoon characters on some of the chips.Any ideas? I looked through google for similar images, and by the chip numbers, but haven't found anything to tell me what they mean.
Circuit design question. - Page 1
Forum section: electronics / general

author: henrysin44
author_rank: Contributor
timestamp: July 15, 2014, 12:49:28 am
content: I have included a picture. In the picture i circled 3 things, my question is how do thees three things correspond to the atmega circuit?

author: Rigby
author_rank: Super Contributor
timestamp: July 15, 2014, 02:15:21 am
content: Schematics nowadays don't have to have everything connected in the diagram.Example, everything that says 5V in that drawing is direcly connected to everything else that says 5V.The "video" pin on the ATmega is connected directly to the "video" pin in the center blue circle. The "clock" and "data" pins in the lower blue circle are connected to the "clock" and "data" pins on the ATmega.Make sense?

author: dsc-pcb
author_rank: Newbie
timestamp: July 27, 2014, 11:37:05 am
content: Agree on 1st floor. It is very typical in block schemetics. For example, the SYNC in the middle is connected to ATMEGA PD5 SYNC. 5V is just from DC supply. Data in the lower circuit you made, is connected to ATMEGA PD0 as input.

author: Wilksey
author_rank: Super Contributor
timestamp: July 28, 2014, 10:36:09 am
content: Those are net labels, a way of joining 2 or more nets together when placing "wires" around the schematic makes it look messy, also useful since the dawn of multiple sheets / hierarchy as you can have the same nets on different sheets quite easily.Most if not all packages support this. When it comes to PCB layout all of the nets with the same name are electrically connected and you can see this reflected in the rats nest.
Anyone found a decent PCB drill to G-Code converter - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 19, 2014, 08:46:57 pm
content: I've spent the last 2 hours trying to find a simple utility to take a standard Excellon drill file and convert to Gcode to drill on a CNCSo far I've yet to find anything that actually works.Amongst the problems :Only understands EagleInsists on doing all sorts of geometry correction for skewed prints and won't just do a simple conversion.Web based tool that won't even pretend to load a fileBarfs on some fields in fileAssumes I want to isolation rout and cut an outline and refuses to just load a drill file and nothing elseAnyone?Do I really have to write my own for such a simple task? How hard can it be?

author: jaxbird
author_rank: Frequent Contributor
timestamp: June 19, 2014, 09:12:42 pm
content: Quote from: mikeselectricstuff on June 19, 2014, 08:46:57 pmI believe many of the most common CNC controller software packages like LinuxCNC and MACH3 will deal with the drill files directly without any conversion needed.But besides that, I don't know any tool that will do the conversion, you will probably have to write your own parser and converter if the above is not an option.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 19, 2014, 09:55:53 pm
content: Just had a look at the output from a util that almost worked and found that there is a G-code that says "drill a hole here", so shouldn't be much effort to roll my own, & make it work the way I want.
Multi-board layout with interconnects in a single file?  Ribbon, headers, etc... - Page 1
Forum section: electronics / general

author: george graves
author_rank: Super Contributor
timestamp: June 15, 2014, 10:44:20 am
content: As the title says basically....How do you define something like a right-angle header in cad? I'm kinda finding it hard to keep track of a three dimensional set up in 2d - both in the schematic and the pcb design - and keeping track of what side of the board is what depending on physical orientation. Any tricks? Define custom connectors in the software? That's the only thing I could think of. Am I missing any tricks?Both in eagle cad, and in soem generic PCB software. Advice?

author: nctnico
author_rank: Super Contributor
timestamp: June 15, 2014, 12:09:11 pm
content: I call right angle connectors 'right angle' connectors in my schematics. I make a physical drawing using Visio (which is a simple 2D drawing program) when dealing with a complex set of boards. If you clearly mark where pin 1 of each connector is in those drawings you have de 3d bit figured out before doing the schematic.

author: free_electron
author_rank: Super Contributor
timestamp: June 15, 2014, 03:44:01 pm
content: Draw the commectors in their location. If, for board one, the connector will sit top right on the pcb, draw it there. On the second board it then needs to sit top left for the boards to be mating.I never really had that problem. Then again i am good at visualising the concept.Make a 3d scribble on a piece of paper that shows what sits where.
Molex connector - Altium question - Page 1
Forum section: electronics / general

author: docmur
author_rank: Regular Contributor
timestamp: June 14, 2014, 07:28:43 pm
content: HelloI need to either find or design the molex connector: 52435-2471 I was wondering if anyone has already designed this.ThanksDocmur

author: 8086
author_rank: Super Contributor
timestamp: June 14, 2014, 07:31:06 pm
content: It's very easy to make parts in Altium, this shouldn't take very long, why not give it a go?

author: docmur
author_rank: Regular Contributor
timestamp: June 14, 2014, 08:05:05 pm
content: Generally I would agree that marking parts is easy but the Datasheet given for this header is almost unreadable with very poor dimensions given. If I have to end up making it from scratch I will but I was hoping to for go that and see if anyone already designed one. I might be able to get away with a 0.5 pitch 24 pin FPC connector from the IPC connector library but I'm not entirely sure.ThanksDocmur

author: 8086
author_rank: Super Contributor
timestamp: June 14, 2014, 08:11:21 pm
content: The drawing seems pretty straightforward to me...Maybe if you make the pads for the pins and then add the 3D model, you can draw the mechanical support pads around the ones on the model?
Change the Behavior of Eagle Schematic Display? - Page 1
Forum section: electronics / general

author: corrado33
author_rank: Frequent Contributor
timestamp: May 26, 2014, 03:23:44 pm
content: Hi all. I've been using Eagle for years, and I enjoy it, but I'm looking for a way to improve the look of my schematics.I get annoyed by the fact that Eagle does nothing when you cross two connections. Generally there is an alternate behavior when two connections cross each other. Usually one connection will be altered to look like it goes AROUND the other connection, see the following random schematic I pulled off of google. The crossed electrical connection is toward the upper center-right or the schematic.http://faculty.frostburg.edu/phys/latta/ee/twinplex/schematic/twinplex%20schematic%20full%20resolution.jpgGenerally with Eagle you have to be careful when you cross connections so you don't confuse which connection goes where.Is there a way to change eagle's behavior for crossed connections?EDIT: Dang, didn't see the Eagle specific forum, if a mod sees this the can move it if they wish.

author: LukeW
author_rank: Frequent Contributor
timestamp: June 02, 2014, 02:37:30 am
content: Eagle will add the "dot" at the intersection of two lines on the same net, and use the "crossed lines with no dot" style to represent lines on different nets.If you want the "loop of wire that jumps up over the other net" style I don't know any way for Eagle to do this. Then again I never see professional schematics drawn in this way.

author: zapta
author_rank: Super Contributor
timestamp: June 02, 2014, 03:05:42 am
content: You can define a bridge component in the library and use in the schematic though it will be tedious to manage.Sent from my Nexus 5 using Tapatalk

author: senso
author_rank: Frequent Contributor
timestamp: June 02, 2014, 05:57:57 am
content: Change the track turn/curve mode from 90/45º to a curve?
Mentor Graphics Xpedition - getting started / tutorial - Page 1
Forum section: electronics / general

author: ppk1982
author_rank: Newbie
timestamp: May 28, 2014, 12:06:02 pm
content: Hi,I recently switched from Cadence Allegro to MentorGraphics DxDesigner/Xpedition.Can anyone help me to getting started with Mentor's environment? May be with some practlcle guide / tutorial etc.-Prasad

author: free_electron
author_rank: Super Contributor
timestamp: May 28, 2014, 02:25:05 pm
content: Good luck !

author: G0HZU
author_rank: Super Contributor
timestamp: May 30, 2014, 12:18:18 am
content: I'm a bit confused by the request...This SW is extremely expensive to buy and maintain and I would assume that training is included in the price? At my place of work we have several seats of Mentor for PCB design but all of our PCB designers go on Mentor training/refresher courses even though we have been using it for many years (and Veribest for many years before that)Also, I'm not sure if it ships with any kind of decent central library for component symbols/shapes. We have built up our own huge central library over many, many years.As a designer, I usually use it for schematic entry and then a PCB draughtsman does the PCB layout. I 'can' drive the Expedition PCB layout tool and create fairly basic PCBs myself but I have to be honest and say that I don't like using Mentor Expedition for PCB layout.It really is designed to be used by PCB professionals to design quite complex multilayer PCBs. There are lots and lots of 'gotchas' in this SW that will catch out a newbie and I wouldn't recommend this SW to anyone unless they do PCB design for a living at a large (and rich) companySo if you fit the description as a full time PCB designer then I would suggest you ask for formal training from Mentor
Books for PCB Layout? - Page 1
Forum section: electronics / general

author: Pariah_Zero
author_rank: Newbie
timestamp: January 25, 2014, 04:45:45 pm
content: Does anyone have reccomendation(s) for books on part placement and routing for PCB's?

author: sacherjj
author_rank: Frequent Contributor
timestamp: January 25, 2014, 05:18:49 pm
content: While I didn't get the book for this, I have learned more from it about PCB layout than most books I've read: Electromagnetic Compatibility Engineering by Ott.I go this to make sure I understood what causes and how to prevent EMI in the new high speed board I am working on, so we can get FCC certification. It gave me a real understanding of pitfalls for high speed circuits.This won't be much help in laying out big power circuits.

author: 8086
author_rank: Super Contributor
timestamp: January 25, 2014, 05:22:21 pm
content: There's always this, written by some Aussie bloke.http://alternatezone.com/electronics/pcbdesign.htm

author: BravoV
author_rank: Super Contributor
timestamp: January 25, 2014, 05:25:59 pm
content: Good book, at least to me, need a registration though, but free for entire book approx. 22MB PDF file.->Lee W. Ritchey -> Right The First Time : A Practical Handbook on High Speed PCB and System DesignEdit: Some of my favourites quoting the book ...Quote

author: HighVoltage
author_rank: Super Contributor
timestamp: March 08, 2014, 08:23:32 pm
content: Year ago, I stared PCB design with the help of a great bookI have been using OrCAD since then.Complete PCB Design Using OrCAD Capture and PCB Editorhttp://www.amazon.com/Complete-Design-Using-Capture-Editor/dp/0750689714/ref=sr_1_1?ie=UTF8&qid=1394310120&sr=8-1&keywords=ORCAD

author: aflex
author_rank: Contributor
timestamp: March 11, 2014, 09:50:57 am
content: Hello Pariah,PCB industry is mainly based on practical. I suggest to have a theoretical knowledge, but more you practice the more you learn.http://goo.gl/dO420Jhttp://goo.gl/mb2DEX

author: Köcki
author_rank: Newbie
timestamp: April 29, 2014, 09:05:42 am
content: there is a good list of books for pcb layout on cadsoft eagle homepage:http://www.cadsoftusa.com/training/books/

author: Towger
author_rank: Super Contributor
timestamp: April 29, 2014, 09:47:23 am
content: Quote from: 8086 on January 25, 2014, 05:22:21 pmFor SMT, this was written by some Belgian bloke.http://www.amazon.com/Mastering-Surface-Mount-Technology-LabworX/dp/1907920129

author: Köcki
author_rank: Newbie
timestamp: May 23, 2014, 09:34:05 am
content: i think i posted this list in another topic before. for me its a very useful list of books on pcb layout. good overview. these are not only about eagle software:http://www.cadsoftusa.com/training/books/
Rimu Schematic/PCB gone? - Page 1
Forum section: electronics / general

author: gregariz
author_rank: Frequent Contributor
timestamp: May 09, 2014, 03:01:07 am
content: I'm a long time Rimu user but I notice that the website of the companywww.hutson.co.nz(Julian Hutson) is down or gone. Is this the end for this package?It still seems available for download at this polish websitehttp://www.alpro.pl/I would have loved to have seen an updated version.

author: TVman
author_rank: Frequent Contributor
timestamp: May 09, 2014, 03:25:54 am
content: Quote from: gregariz on May 09, 2014, 03:01:07 amIt may have Doo Doo down

author: Bloch
author_rank: Unknown
timestamp: May 18, 2014, 04:55:13 am
content: >It still seems available for download at this polish websitehttp://www.alpro.pl/It seems that is the Poland Distributorhttps://web.archive.org/web/20130810084658/http://hutson.co.nz/disti.htm]https://web.archive.org/web/20130810084658/http://hutson.co.nz/disti.htm
16 Layer Board PCB 1 GHZ clock - Page 1
Forum section: electronics / general

author: Mitz
author_rank: Newbie
timestamp: May 17, 2014, 01:47:51 pm
content: What are the PCB Design consideration while designing a board with a signal layer of 1 ghz clock with 16 layers PCB. Can anybody help with a case study? I need a design with 1 ghz clock . Like routing from processor to a DDR3.? I am an OrCAD trainer so I will use PCB designer and ORCAS SI .

author: TiN
author_rank: Super Contributor
timestamp: May 17, 2014, 02:09:43 pm
content: Intra-pair length matching, correct impedance (which depends on design topology and used memory controller), solid reference planes.Basically you want to minimize signal integrity issues as much as possible, while still maintaining design specs.Also in memory buses it's also important to match data and control signals in relation to each other, so your data will arrive in correct setup/hold windows.For particular examples you can take a look of DDR3 implementations using Altera or Xilinx FPGA's.

author: free_electron
author_rank: Super Contributor
timestamp: May 17, 2014, 02:37:36 pm
content: Layer stack is important. Where you put the power and return planes, the prepreg thickness.That is going to drive the width and clearance you can attain to maintain impedance.Next up is length equalisation.And keep track of the return currents. At 1Ghz you are strongly coupled. So any moat in the return is a disaster (watch out for plane starvation due to via and pad thermal spokes)

author: nctnico
author_rank: Super Contributor
timestamp: May 17, 2014, 03:03:11 pm
content: 16 layers is a lot! My SoC designs usualy have 6 layers. You can reduce the number of layers significantly by using a power plane as a reference plane for high speed signals. The only caveat is that you need to place capacitors between the planes where (and if) a high speed signal changes from one reference plane to another so the return currents have a proper path. With some optimisations it usually is possible to keep all DDR3 data and clock traces on the top layer.

author: Mitz
author_rank: Newbie
timestamp: May 17, 2014, 03:38:18 pm
content: Thank you guys.
2014 PCB CAD preference POLL - Page 1
Forum section: electronics / general

author: scientist
author_rank: Frequent Contributor
timestamp: May 12, 2014, 04:32:16 am
content: Vote for your preferred circuit CAD software. You may vote twice, if you have no second choice pick "MS Paint/Notepad."If your favorite CAD software isn't on the list, comment and I'll add it.

author: nctnico
author_rank: Super Contributor
timestamp: May 12, 2014, 03:42:48 pm
content: Orcad has (at least) two PCb layout packages: Orcad Layout and Allegro PCB Designer.

author: scientist
author_rank: Frequent Contributor
timestamp: May 12, 2014, 10:34:24 pm
content: Added.

author: pipe
author_rank: Contributor
timestamp: May 13, 2014, 03:45:47 am
content: I couldn't find DaveCAD in the list.

author: AndyC_772
author_rank: Super Contributor
timestamp: May 13, 2014, 04:11:17 pm
content: No mention of PADS or Expedition?"Orcad" is a schematic capture tool. "Orcad Layout" is the old, deprecated PCB software that used to go with it, but that's now been replaced by "Orcad PCB Designer" which is actually a license-nobbled version of Allegro.

author: janoc
author_rank: Super Contributor
timestamp: May 13, 2014, 04:18:24 pm
content: Quote from: scientist on May 13, 2014, 03:41:05 pmWell, there aren't that many alternatives for a cash-strapped hobbyist, even less so for one not using Windows.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 13, 2014, 04:30:24 pm
content: Quote from: AndyC_772 on May 13, 2014, 04:11:17 pmor PCAD

author: abaxas
author_rank: Regular Contributor
timestamp: May 13, 2014, 06:27:25 pm
content: No pen, acetate sheet and artistic flair option?

author: scientist
author_rank: Frequent Contributor
timestamp: May 13, 2014, 07:03:51 pm
content: Quote from: mikeselectricstuff on May 13, 2014, 04:30:24 pmBut is PCAD your preferred EDA software?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 13, 2014, 10:32:10 pm
content: Quote from: scientist on May 13, 2014, 07:03:51 pmYes.

author: kile
author_rank: Contributor
timestamp: May 14, 2014, 06:27:50 am
content: Quote from: scientist on May 13, 2014, 03:41:05 pmI'm a hobbyist and I've used Eagle for about 2 years. Actually, I've learned whatever little I know about schematic/pcb layout through Eagle. It was a very long and painful process and I bitched and moaned all the way through. Once I tried to use KiCad for about half an hour and hated it. Then, about two months ago, I had to design a pcb which had to be larger than the 10x8cm Eagle allowed. So I tried learning KiCad again. This time, I was really surprised how easy it was. Most of things I did in Eagle were simpler and more intuitive in KiCad. And then I learned that I can import my footprint library from Eagle into KiCad. And that was a nail in Eagle's coffin as far as I'm concerned. I'm not going back, except to make revisions of designs I already have in Eagle.There's nothing I need to do with a schematic/pcb that's easier in Eagle than in KiCad. Who knows, maybe it's because I'm just not aware of Eagle's full potential.
Adding Through-hole Pads in FreePCB - Page 1
Forum section: electronics / general

author: Dipski
author_rank: Contributor
timestamp: June 08, 2014, 03:28:39 pm
content: Hi folks,I decided to take a circuit I've built a number of times on perf board and give it a proper board to sit in. It's my first time using PCB designing software, and I'm using FreePCB. Unfortunately I first downloaded ExpressPCB (and then realised that it only outputs the file type for their own board printing company), but in ExpressPCB placing a pad is really simple - and something I need to do as I have through-hole cable connections on the board. I can't for the life of me find a way to do it in FreePCB, the closest I could find was a Test Point and there were only about 2 options that looked like they could work at all. Could someone please steer me in the right direction, I'm guessing that I've missed something blatantly simple
What is a good heat dissipation solution for stepper motor driver? - Page 1
Forum section: electronics / general

author: gcardinal
author_rank: Unknown
timestamp: April 30, 2014, 07:38:55 am
content: Good day,I'm currently working on PCB where I will mount 4 x PololuDRV8825/A4988stepper motor drivers.Standard height 2.54mm pitch female header on PCB and A4988 plugged into it. Those chipo stepper motor drivers do produce quite a lot of heat.Driver it self has exposed solderable ground pad with vials to help it dissipate its heat.Im looking for a solution to aid in heat dissipation from those drivers on my PCB. I have considered a few options:1. Cut out underneath the driver board - since my PCB will be mounted 2cm above the case I think it can aid in air circulation.2. Go for the same solution as on the driver board it self - go nuts with vials.Any tips and trick would be highly appreciated.

author: peter.mitchell
author_rank: Super Contributor
timestamp: May 01, 2014, 02:29:53 pm
content: thermally conductive epoxy + small heatsink.

author: SeanB
author_rank: Super Contributor
timestamp: May 01, 2014, 03:15:56 pm
content: Thermopad about 5mm thick covering the whole back of the board ( trim pins so they do not project above surface) and a flat heatsink used to keep the pad about half compressed and holding the COB unit to the main board. You probably could get by with a flat bar across the whole row and a screw at each end if it is about 10mm thick.
PCB manufacturers capabilities - Page 1
Forum section: electronics / general

author: Richard Head
author_rank: Frequent Contributor
timestamp: May 02, 2014, 07:16:51 am
content: I routinely layout my own PC boards and have come up against a limitation.I would like to make more use of smaller smd components such as 0603 and 0402 but find it pointless due to the PC board manufacturers track width and spacing limitations.The PCB manufacturers that I use have a 0.2mm minimum track width and spacing and a 0.4mm minimum hole size limitation.This means that when one uses components smaller than 0805 you can't fit a track between the leads without violating the 0.2mm limitation.I know using a multilayer board would solve the routing problem but I try not to use them due to their high cost.Well inspecting commercial PC main boards and found them to have extremely thin tracks. How do they get away with such thin tracks on such a large scale?Is the 0.2mm width/spacing rule of my PCB manufacturer unnecessarily conservative?Dick

author: Neverther
author_rank: Regular Contributor
timestamp: May 02, 2014, 07:40:13 am
content: They produce a load of the boards, they can afford to use (and incase of the PCB has errors, redo as many time as they need the templates) high quality/precise setups as they are ran trough the same setup multiple times. The volumes are on completely different scale so the costs per board arent that bad.And they can afford to test and reject some boards as they are being constantly made.When you use prototyping services/small houses, they might not have enough precision on their machines to do so, or the cost of manufacturing precision boards comes cost ineffective (failed templates, small batches, one run with some failed boards -> possible need for another run to produce enough boards, etc).You can always ask the manufacturer if they can and how much it would cost to have smaller clearences.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 02, 2014, 07:48:30 am
content: Different manufacturers have different capabilities - It is not uncommon to find specs down to 4 mil (0.1mm) track/space with drills down to 0.1mm, e.g. PCBcart, but you will pay extra for it.Don't expect OSHpark/iteadstudio type pricing, but there are poolling services that offer fairly fine pitches, e.g. Eurocircuits

author: poorchava
author_rank: Super Contributor
timestamp: May 02, 2014, 08:18:14 am
content: Chinese low cost board houses like itead and elecrow offer down to 6/6 mils which is 0.15/0.15 mm. With some adjustments to the footprints you can pass tracks underneath 0603 without problem.

author: Allen393
author_rank: Contributor
timestamp: May 02, 2014, 09:11:41 am
content: process capability with min 0.2mm trace width/spacing and min 0.4mm hole size is limited indeed, most of china pcb manufacturers are able to achieve min 0.127mm trace width/spacing and min 0.2mm hole size nowadays, and it's low cost with this spec..

author: Richard Head
author_rank: Frequent Contributor
timestamp: May 02, 2014, 09:56:27 am
content: The feedback is much appreiciated. Perhaps it's time I looked around for another manufacturer.
Negative layers in gerbers and pcb fabs - Page 1
Forum section: electronics / general

author: varesa
author_rank: Contributor
timestamp: April 22, 2014, 10:52:16 pm
content: I am designing a 4 layer pcb in Altium which has a ground plane. Altium seems to want to make it a negative layer, which carries on with the exported gerbers (checked with gerbv). With a quick googling it seems that Altium itself atleast tries to detect negative plane layers if you try to import gerbers, so there is some difference.If I send the gerbers off to a PCB fab, do I have to manually invert that layer to get a "non-negative" one, or will they somehow know at the fab that it is in fact a negative layer?

author: toohec
author_rank: Contributor
timestamp: April 22, 2014, 11:27:09 pm
content: If you use the Gerber RS-274X format (and perhaps even the prior version), the positive and negative layer information is imbedded in the file format and will not require you to invert the negative plane layers. The fab house should be accustomed to working with negative plane layers, however, it's best to specify on your fabrication drawing/notes details about the layers types to prevent any possible confusion.

author: Psi
author_rank: Super Contributor
timestamp: April 22, 2014, 11:29:12 pm
content: Open your 'ready to send' gerbers in a different gerber viewing program and see if they all make sense before sending.

author: varesa
author_rank: Contributor
timestamp: April 23, 2014, 08:13:05 am
content: Okay, I might just send them as is and specify it in the comments to avoid any problems.I did try them in two gerber viewers: Altiums internal one and Gerbv, both showed the negative (voids) by default. To see the copper, I had to manually enable "negative"-mode
PCB design for multiply packaged versions of same component. - Page 1
Forum section: electronics / general

author: abaxas
author_rank: Regular Contributor
timestamp: May 05, 2014, 10:08:55 am
content: Lets say you wanted to do a layout that accommodated both SMT and through hole versions of the same component, how would you do this?Eg. 741 opamp is available inand...Hence I would want to design a board so you could use both the SOIC and DIP versions. How would people approach this?I'm using eagle so I guess I could just double up everything in the schematic. But there must be a more elegant or standard way as it's not exactly uncommon to find this out in the wilds.

author: sacherjj
author_rank: Frequent Contributor
timestamp: May 05, 2014, 11:01:37 am
content: If the SMT footprint will fit inside the TH footprint by enough to offer solder mask, then you can just put it in the middle. This may be a situation where a much smaller SMT footprint is helpful.The problem you will run into is if the copper for TH and SMT touch. That is inviting solder to get sucked down the rabbit hole and leave your SMT component with no solder.I would probably make a footprint that is two in one, with it shifted to the side.Something like this with 'O' being a TH pad and [] being an SMT pad.Code:O--[] O--[]O--[] O--[]O--[] O--[]O--[] O--[]You could look at the TH pads as free big vias for routing the SMT part, I guess.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 05, 2014, 11:26:14 am
content: or like this if it fitsCode:O--[] []--OO--[] []--OO--[] []--OO--[] []--Oi've seen its commonly done for TQFP of various chip sizes in breakout or test board sold in ebay or something. but it will limit your capability to route under and between pins of the TH. btw i wonder if its common for other "mainstream" softwares like altium or cadence to make a single component with multiple footprints combination (with the schematic component) capability. decision to change ic package later (after circuit design or pcb layout) is as simple as selecting another fp in the component setting without the need to this overlapping TH/SMD hack. need to check this one out.

author: sacherjj
author_rank: Frequent Contributor
timestamp: May 06, 2014, 01:06:37 am
content: Quote from: Mechatrommer on May 05, 2014, 11:26:14 amYep, that is exactly what I would think for SMT fitting inside.QuoteCan't speak for Cadence, but in Altium you define a schematic. Then you associate 1 or more footprints. You can pick the footprint at any time and change it after you routed the PCB (just have to fix up the differences).

author: scientist
author_rank: Frequent Contributor
timestamp: May 08, 2014, 03:36:47 pm
content: KiCad can do this. Just select different footprints in Cvpcb.
Yet another Altium issue - Page 1
Forum section: electronics / general

author: docmur
author_rank: Regular Contributor
timestamp: March 28, 2014, 12:27:54 pm
content: Hey GuysI've seen this in another post but that thread didn't help me.I'm working on a new simple project where I've made most of my components. I've made about 1/2 of all my foot prints and the other half are from the IPC standard footprint libraries. My issue is that when I go to update my PCB I get the always annoying error:All of my nets seem to have pin errors. I've made sure all my pins line up with the foot prints I've used, 1 -> 1 and 2 -> 2 and I've made sure all my port pins in my schematic are physically connected to the pins of the chips. I'm lost on what to try next, I've ran into this before but never really known what to do, usually I just go ahead and redesign all my footprints and link them back into the schematic.It's errors like this that make me serious wonder how Altium can charge money for this program, given that it's only job is to effectually make a record of pin connections.ThanksDocmur

author: kikib
author_rank: Contributor
timestamp: March 28, 2014, 01:00:10 pm
content: Typically that happens when the schematic library can't link up with the footprint library, meaning it can't find the footprints.In the schematic editor, open up the component property window of one of the parts in question. Then select the footprint model in the list at the bottom of the window. Hit the edit button which will then open up the footprint window. Does it show the footprint there?

author: docmur
author_rank: Regular Contributor
timestamp: March 28, 2014, 02:01:46 pm
content: Thanks for the advice!That was the first thing I checked, I made sure all the footprints are still accounted for, I also clicked on the "Edit Pins" button to make sure the pin mapping was correct.The second step I looked at was the connection Matrix and made sure all my connected weren't causing errors, which they aren't.I checked my library path and installed library path and they check out. I'm still stumped.ThanksDocmur

author: ElektroQuark
author_rank: Unknown
timestamp: March 28, 2014, 02:14:20 pm
content: Check that schematic symbol and footprint pin names are identical.

author: Rufus
author_rank: Super Contributor
timestamp: March 28, 2014, 02:54:54 pm
content: Quote from: docmur on March 28, 2014, 12:27:54 pmWhen an ECO places components on the PCB validation shows errors for pins which don't exist because the component has not yet been placed.Execution of the ECO will not actually produces those errors if the placed components have the required pin names.
What are the contents of a Gerber "Board Outline" File (.gko)? - Page 1
Forum section: electronics / general

author: jrkirk
author_rank: Newbie
timestamp: March 25, 2014, 08:25:20 pm
content: I'm in my 14th week of developing a "minimalist" PCB Layout Program. The program will only handle the design of a 2-layer board and would be perfect for beginners.I'm going to use it mostly for designing small development boards that use Atmel AtMega chips.The layout program is 95% complete and I'm wrapping up the Gerber File and Excellon Drill File Generation.The only thing missing is the layout of a Gerber Board Outline File (.gko). I'm sure there's not much to it, just a few lines of text.If someone could rummage through their Gerber Files and please give me a heads up sample of a Standard Gerber RS-274-D Board Outline File (.gko). My board is 1.7 inches wide and 1.3 inches high.It probably starts and ends in accordance with the below snippet.%FSLAX26Y26*%%MOIN*%...so...what goes in here?...M02*Thanks much!!!

author: Thor-Arne
author_rank: Unknown
timestamp: March 25, 2014, 11:04:11 pm
content: Here's a small one I made with rounded corners.

author: jrkirk
author_rank: Newbie
timestamp: March 26, 2014, 03:42:49 am
content: Thanks Thor Arne,That helped a lot.My Gerber file generation is now complete.
Good Componet Library Practices - Page 1
Forum section: electronics / general

author: VK3DRB
author_rank: Super Contributor
timestamp: March 24, 2014, 11:28:25 am
content: One of the big problems some companies have iscomponent libraries. That is, they are not maintained properly, have bugs, and they end up not being trusted. One company I worked for had several libraries by different teams because there was no trust and little cooperation between the teams... a BIG waste of money and time.Here are some ideas that seem to work:First of all, have PCB Design Standards for Guidelines within your company that everyone can work within.A really good idea is to have TWO sets of libraries. As an example, the libraries would be named:(1) Component Libraries - these are libraries of parts, also containing component footprints.(2) Verified Component Libraries - this are libraries of verified correct parts, also containing footprints WHICH HAVE BEEN VERIFIED to be correct as evident on new boards. These verified parts are moved from Component Libraries into the Verified Component Libraries when a new board arrives.Then you can use footprints from (2) with complete confidence - not double checking needed. Those new components in (1) might need to be double checked with their datasheet before being used.I am interested to know other ideas people have in maintaining libraries. What standards do you use in maintaining libraries? Do you think a strict standards operating component libraries is a good or bad idea? Any war stories?

author: peter.mitchell
author_rank: Super Contributor
timestamp: March 24, 2014, 04:28:08 pm
content: One thing i found very useful is keep the footprint name short and simple, but add as much as you can to the description text.That way it all stays neat but you can identify what packages work with what footprints still.Another thing, different manufacturers have different names for the same footprints, and there are footprints that can be used between a lot of different packages (eg, a universal power so-8 footprint that can do LFPAK,PG-TDSON-8,PowerFLAT,8-HVSON), using custom footprints that allow compatibility between multiple packages can help with design changes, part compatibility and minimize confusion.
USE DLP 3W UV LED to create PCB with dry-film photoresist - Page 1
Forum section: electronics / general

author: theparitt
author_rank: Newbie
timestamp: March 18, 2014, 02:36:00 pm
content: I am planning to buy a DLP machine with 3W UV (385nm) LED ( 30% reflection power about 900mW on a pcb surface). Is it possible to do so? Has anyone ever tried this method before? I feel it is faster than using Laser printer with Toner transfer? and more precise....

author: Refrigerator
author_rank: Super Contributor
timestamp: March 18, 2014, 04:18:45 pm
content: Here, this should help you.Good luck!

author: ovnr
author_rank: Frequent Contributor
timestamp: March 19, 2014, 12:58:46 am
content: Well, some things to keep in mind:* Resolution. Let's assume you're making a 3"-wide board (~75 mm) and using a 600 DPI laser printer - the bare minimum IMO. You'd get 1800 pixels across the board. Now, most LED DLP projectors are 800x600 at best; this will severely restrict your line pitch. The projected pixels would be around 0.1 mm, which is a lot if you want to do fine-pitch stuff (most of my traces are 8-mil, or 0.2 mm - you'd be lucky to properly do 0.4mm traces).* Optics. Will your projector actually project a flat image onto the board, or will the corners be blurred? If they are, it's useless.Also, will it project sharp pixels or blurry blobs? Will it focus close enough?* Contrast ratio. If your contrast ratio is too low, you may easily expose all the photoresist, not just the one you want to expose.* Boards. You will need either pre-sensitized boards (coated with photoresist) or laminate your own boards, which seems like a huge pain. You'll also need a developing step which isn't required when using toner transfer.Now, for the positive things: It should work, assuming the above conditions have been fulfilled. I was playing around with drawing random patterns using a UV/blue laser on some scraps of board I had lying around, and it worked a treat - it exposes really quickly, even at just 10-20 mW. If you drop a pre-sensitized board in developer solution and shine a laser at it, you can see it change pretty much immediately, trailing a tendril of "smoke" (dissolved photoresist) after it.But all things being equal, unless you need to either make VERY large boards or need them in a hurry but isn't willing to pay for a quick service, just go to Itead or Seeed. They're fast enough for hobby work, have very reasonable prices, and the quality is perfectly fine.

author: theparitt
author_rank: Newbie
timestamp: March 19, 2014, 05:05:46 pm
content: ovnr .. thanks for your comment.. I will also consider the tradition methodfor making a pcb.. it seems much much cheaper with very good quality

author: Refrigerator
author_rank: Super Contributor
timestamp: March 19, 2014, 05:46:27 pm
content: You can also buy uv solder mask for cheap on ebay.
Avoid octagons?  Why? - Page 1
Forum section: electronics / general

author: bronson
author_rank: Regular Contributor
timestamp: March 11, 2014, 10:56:30 pm
content: Quoth Dave in 2004: "Octagonal pads are seldom used, and should generally be avoided."http://alternatezone.com/electronics/files/PCBDesignTutorialRevA.pdfI actually like octagonal vias better than round and square. They're the best of both worlds: like round they can be nicely skirted using 45deg lines and packed tighter, and like square they make it obvious when the grid is off and tracks aren't passing symmetrically between vias. When the density is high, I like the way they look.When routing around round/oval vias, a track can be pretty unbalanced before my eye will catch it. With octagons, I find them immediately obvious.I'm happy to use round or square of course, whatever the client wants. I just tend towards octagon. Am I missing something here?EDIT: Oh, Dave's talking about PADS. -EREADINGTOOFAST. But my question is still this: why don't more people use octagons? I tend to leave pads oval but, if I'm running a bunch of traces around them (like through the pins of a wide header), I'll make them octagonal and marvel at how much neater it makes it look. Any downside?

author: free_electron
author_rank: Super Contributor
timestamp: March 11, 2014, 11:33:27 pm
content: some gerber importers have problems with octagon pads. they become rectangles .... without the chamfered corner... and then you get shorts.

author: bronson
author_rank: Regular Contributor
timestamp: March 12, 2014, 01:08:37 am
content: Nasty! But has that been an issue since the 90s?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 12, 2014, 01:38:05 am
content: Never heard that beforePersonally, I've never use 'em... because they're ugly!I do prefer rounded rectangles for "square pin 1" pads though.. just to take the edge off.Tim

author: free_electron
author_rank: Super Contributor
timestamp: March 12, 2014, 02:02:33 am
content: The problem has gone away. Some mom and pop shop still photoplotting and using outdated softwaref rom before 2000 may still have this problem. Cam350 was notorious for weirdness.Even UCam had problems. Same for oblongs (rounded rectangles. I mean real rounded rectangles. Not a rectangle where two opposite ends are semicircles.)The problems is the photolotters.The apertures are made with a slit and a diaphragm. Flashing circles, rectangles squares is no problem. A rectangle with opposite semicrcles is no problem. Open aperture for a circle and move the head while it is open.Component pads in Gerber format are defined as flashes: go to coordinate : set aperture for square or circle, light on light off.Anything else needs approximation and that is where misery begins.With the addition of arbitrary polygons in gerber standard this was solved. But not all cad programs could handle those.

author: bronson
author_rank: Regular Contributor
timestamp: March 12, 2014, 04:11:24 am
content: OK that's a great explanation. Makes sense once you hear the full story.Figure I'll lay them out octag and switch to whatever the customer wants before generating gerbs. Everyone's happy!
AC power ground fill? - Page 1
Forum section: electronics / general

author: djacobow
author_rank: Super Contributor
timestamp: February 14, 2014, 12:02:12 am
content: I'm working on YALDP (Yet Another Light Dimmer Project). My question is primarily about ground and power planes.I've already made a revision of this board that works fine except for a couple of minor bodges, which I'm clearing up in this go. My first board also did not use planes, and I was thinking I should do so this time.This board is organized into a DC side and an AC side. The parts between them are optos and there is no electrical connection between the sides whatsoever. The PCB has route-outs under the optos.I decided to add Vcc and Gnd ground planes on the DC side because everyone says this is better -- though the benefits seem to accrue mainly to the fab house. Is this worth doing? They planes OK to me, but I'm a noob at PCBs.I am also considering adding planes on the AC side. Of course, they would not be connected to those on the DC side. I was thinking of AC_GROUND on the bottom and AC_NEUTRAL on the top.1) is this safe?2) is there any reason to do this?To me, it looks funny and brings NEUTRAL close to various HOT traces in many more places than they would otherwise be, and this might encourage arcing. On the other hand, it's not like those traces don't come together at the triacs and other spots, so maybe no big deal.On the AC side I have the "isolate" set to 0.07. It's 0.024 on the DC side.I'm also open to other general feedback.Regards,Dave JPS --I am an EE and understand the dangers of AC power. I also know that I don't know enough to make a board that would pass UL et al approval. That's not my aim. I only want to make a reasonably safe board that I can use around the house for some home automation projects.

author: AlfBaz
author_rank: Super Contributor
timestamp: February 14, 2014, 02:10:50 am
content: I guess the question is, are there any benefits crucial to the operation of this device afforded by those planes on the AC side or is there an alternative to shield against switching noise. When doing risk analysis the first port of call for hazards is their elimination

author: djacobow
author_rank: Super Contributor
timestamp: February 14, 2014, 02:45:39 am
content: Thanks for the reply. If I understand, I think you're suggesting that unless I can come up with a reason to do this, I shouldn't. Well, on the AC side, no, I don't see how these will help, and can probably hurt by forming antennas to radiate EMI and by in general making bridges more likely.I'm taking the AC planes out.