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Rescue Toaster posted:Generally, anything other than basic capacitors/resistors and pin headers, I basically create symbols and footprints myself. You are going to have to get into the library editor a lot eventually anyways, so you might as well get started. The stock libraries aren't usually a good fit for anything so I pretty much always create my own footprints as well. At least then, you have noone to blame but yourself when it's wrong 
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Jul 1, 2013 17:42
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Delta-Wye posted:The stock libraries aren't usually a good fit for anything so I pretty much always create my own footprints as well. At least then, you have noone to blame but yourself when it's wrong I'm really, really lazy, so I try to use as many stock parts (or at least generic footprints). The generic footprint libraries are really hit or miss, especially when a company isn't consistent with their usage of a particular name for a package. But if it matches up with what I want, it's usually a process of just checking all of the dimensions, checking that the additional layers are setup right, the usual. A lot of times there are errors like the pad sizes being hilarious wrong compared to the datasheet, or the soldermask layer being a complete shitshow, or something like that.
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Jul 1, 2013 17:57
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Okay, so say I'm going to design my own footprints just for practice. Any guides on doing that properly or what I should aim for?
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Jul 1, 2013 17:59
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Bad Munki posted:Okay, so say I'm going to design my own footprints just for practice. Any guides on doing that properly or what I should aim for? Remember that suggested PCB land pattern from a datasheet is just that: suggested. You can modify them slightly to make things easier for hand soldering, as most of their documentation (for SMT at least) is geared to machine assembly. I.E. for a TSSOP or something, you could make the pads longer length-wise to give you more room for hand-soldering.
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Jul 1, 2013 18:20
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Slanderer posted:I'm really, really lazy, so I try to use as many stock parts (or at least generic footprints). The generic footprint libraries are really hit or miss, especially when a company isn't consistent with their usage of a particular name for a package. But if it matches up with what I want, it's usually a process of just checking all of the dimensions, checking that the additional layers are setup right, the usual. A lot of times there are errors like the pad sizes being hilarious wrong compared to the datasheet, or the soldermask layer being a complete shitshow, or something like that. I will often copy existing footprints into my library if I'm feeling lazy but to be honest, it takes me nearly as long to check them as it does to just create the footprint. Once you get used to putting coordinates into the commandline, it's as easy as figuring out where the edge pad goes and then just typing in the coordinates one after another. There is probably an even easier way, but that is pretty fast for me. movax posted:Remember that suggested PCB land pattern from a datasheet is just that: suggested. You can modify them slightly to make things easier for hand soldering, as most of their documentation (for SMT at least) is geared to machine assembly. I.E. for a TSSOP or something, you could make the pads longer length-wise to give you more room for hand-soldering. Always extend your leads on SMD parts, it makes a huge difference when you're cleaning up after a sloppy pass of drag soldering.
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Jul 1, 2013 18:31
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I just found out the other day eagle had make-symbol-device-package-bsdl.ulp, which seems like it might make making components much easier than doing everything manually.
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Jul 1, 2013 18:51
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I've had good luck so far with Sparkfun's Eagle library. Most common parts are already in it, and the descriptions are actually useful when you're browsing through it. I just rip off their footprints whenever I need to create a new part, and it's worked well for me.
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Jul 2, 2013 03:09
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Man I ordered my PCBs from Seeed because I thought I wouldn't mind waiting for shipping from China, but I think next time I'll just go with OSHPark and pay a little more for the convenience of not having a two week and change turnaround time. I'm assuming my board will get here this week but meh.
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Jul 2, 2013 19:02
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I haven't done any Eagle PCB layouts in years - are there not large "open source" / crowd-sourced libraries available? I figure that would be a pretty obvious thing people might want to contribute to, given its usefulness.
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Jul 2, 2013 19:16
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There are, and even large libraries that come with it, but that's where a large part of my problem comes in: how do I choose between a thousand different variations for a cap footprint? Choice paralysis.
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Jul 2, 2013 19:23
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I'll echo the use of SparkFun's libraries and add in that Adafruit's library is likewise excellent. For most new components, I'll search the existing libraries for a footprint and if it's already there, copy it to my own library. Modify and rename the symbol and device, done. If you're trying to find footprints for through-hole stuff like 1/8W resistors then yeah, I bid you good luck. A caliper, measuring in the library editor and lots of datasheet reading will get you there eventually. I gave up and moved to SMD components which don't have as many variants. Saves a ton of PCB space too.
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Jul 2, 2013 21:05
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I like Fritzing 
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Jul 2, 2013 22:07
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With a decent temp-controlled iron (not a firestarter pen) and a flux pen/needle you'll find that SMD parts are quicker and easier to solder anyway. No bending and clipping leads. Plus the aforementioned space savings on the PCB and far fewer variants to deal with. Start with 0805's everywhere, and try to only use 0603's when you really need to fit them in, and it should be fairly easy even for a first-time SMD solderer. Dangerous Prototypes also has an eagle library I think, they also have a nice parts guide for standard parts they use everywhere with links to mouser/digikey.
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Jul 3, 2013 02:23
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Speaking of SMD iron-soldering, what sort of tip is preferred for working with 0805? I have a temp controlled Weller that takes tips, but I only have a rather blunt round tip. I'm not really sure how to describe it but I'm wondering what people prefer to use.
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Jul 3, 2013 02:26
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I have a Hakko 936/907 and use the T18BL for small stuff like SMD resistors (http://www.amazon.com/Hakko-T18-BL-Soldering-FX-8801-Conical/dp/B00762AGTA), and it works well for that, but to solder the little fine-pitch ICs I think you'd want something in a similar size but with the oblique tip that looks like they sliced the edge off a cone at an angle. I've never tried soldering an SMD IC before so I dunno though.
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Jul 3, 2013 03:02
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I use the long conical tip on my Weller to solder 0402 components by hand. Put flux on the board. Put some solder on the tip. Hold the component with tweezers. Touch the tip briefly to the component. If I'm doing an IC, then I hold the tip perpendicular to the pins and drag it across.
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Jul 3, 2013 03:51
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Personally I can't stand conical tips. Basically I use a 1.5mm chisel tip (SSC-638A) for virtually everything down to 0603. SMD IC's I use a drag hoof (SSC-639A), although that didn't work so hot on a 0.5mm QFP that didn't have much exposed pad past the legs. But I just cleaned it up with the 1.5mm chisel and it's fine.
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Jul 3, 2013 13:54
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Martytoof posted:Speaking of SMD iron-soldering, what sort of tip is preferred for working with 0805? I have a temp controlled Weller that takes tips, but I only have a rather blunt round tip. I'm not really sure how to describe it but I'm wondering what people prefer to use.
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Jul 3, 2013 14:13
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So many goddamned devboards 
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Jul 3, 2013 21:23
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I'm creating a BOM and I need the package of each component, but I've run into a problem specifically with this. The problem is there are 3 different packages listed(8-VSSOP,8-TSSOP,8-MSOP), and on top of that the description that now reads "IC OPAMP INSTR R-R 500KHZ 8VSSOP" used to say "IC OPAMP INSTR R-R 500KHZ 8MSOP." I have 3 questions regarding these packages: 1. What is the correct package? 2. When the PCB was designed it assumed the part was an 8MSOP, if that is not the correct package will the design need to be changed? 3. If it isn't 8MSOP would it have affected assembly if I had listed it as 8MSOP?
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Jul 3, 2013 23:14
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You always need to double-check the datasheet to verify the package against the part number. Distributors don't guarantee that the product data is correct (in fact it almost never is perfectly correct, and more often than you'd think the package is wrong even). The only guarantee they make is that you're going to get the part number it says. According to the part's data sheet, INA321EA is a MSOP-8. The CT means Cut Tape and the -ND means No Discount which is just an ancient digikey holdover.
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Jul 4, 2013 00:27
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Rescue Toaster posted:According to the part's data sheet, INA321EA is a MSOP-8. The CT means Cut Tape and the -ND means No Discount which is just an ancient digikey holdover.  That's what it means!
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Jul 4, 2013 00:38
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One digikey mystery solved! The big one is how do they ship my stuff so goddamn fast!? It's creepy! (but awesome)
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Jul 4, 2013 00:41
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Back before the internet basically, when everyone ordered from their catalog or the sales reps, they'd (supposedly) have discounts on orders above a certain price, -ND items excluded. Except I don't recall ever actually seeing a product that wasn't -ND. As for their speed, I used to complain about how often big IC's were $1-2 more than mouser. But they virtually always ship same day. One order I placed which wasn't even particularly small was packaged & 'shipped' in less than an hour. Also, the Minnesota warehouse is next day via USPS for me, which is double-awesome. I've waited two weeks for parts from mouser in order to save 5 bucks. Never again.
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Jul 4, 2013 00:51
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Yeah I'm in the lower mainland of BC, Canada and if I place an order even around 5PM it is there first thing the next day and I've never, ever had any other stuff ship that fast. For $8 shipping, it's insane!
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Jul 4, 2013 01:09
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That's pretty awesome. I have a company account with Newark and we get free next-day UPS shipping for "free" (I mean I'm sure the university pays for it somehow, I just never see it on my invoice) but for personal stuff I might have to check that out. $8, you can't really beat that.
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Jul 4, 2013 01:26
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Hum, I find Mouser's site much more tolerable to navigate when I'm looking for parts based on parameters instead of by part number, I may have to start building a shopping card on Mouser and ordering stuff from Digikey to see if the shipping is less murderous.
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Jul 4, 2013 01:28
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Back when I worked for a place that needed a lot of little connectors and things like that, Mouser was often better than the company that built the drat things when it came to documentation.
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Jul 4, 2013 02:00
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Delta-Wye posted:Hum, I find Mouser's site much more tolerable to navigate when I'm looking for parts based on parameters instead of by part number, I may have to start building a shopping card on Mouser and ordering stuff from Digikey to see if the shipping is less murderous. Hmm I've always been a digikey guy. The site doesn't look great but the times I've tried to look at mouser I haven't been able to find things as easily. I think digikey has wider stock also. Though I should give mouser another chance sometime.
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Jul 4, 2013 04:08
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Sonofabitch. That's got every widget I want to use built right in. Bye bye, $75! (thanks for the link  )
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Jul 4, 2013 19:46
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I've been meaning to post about this, I backed it as soon as I saw them put a new subforum up on their website (after googling the name to find out what the hell it was). I have no doubt that these guys will be able to get the board out there and meet their goals.
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Jul 5, 2013 08:33
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The routing on that board is making me feel vaguely uncomfortable
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Jul 5, 2013 13:29
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OSHpark: Do you guys happen to know what their rules on panelization are? Seeed wouldn't allow any panelization by means of drill holes, etc. It had to be stencil then DIY-cut. I have four small boards (like 3cm x 5cm) that I'd like to maybe panelize roughly by adding drill-holes as an easy-break. My board seems to pass their design rules check but they don't seem to have an explicit panelization thing on their site that I can find. Unless I'm just looking in the wrong place. I contacted them and I'm sure they'll get back to me, but I figured I'd fire off a question here too.
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Jul 5, 2013 15:24
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Martytoof posted:OSHpark: IIRC, he doesn't care what your board has (including internal routes) as long as it meets his requirements from the fab. I'm pretty sure he panelizes them himself already so the fab doesn't care about that; if you either draw cut lines or make a routed channel roughly the same size you'll be okay.
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Jul 5, 2013 16:17
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Oh neat. That'll save me considerable effort. Going to head in this direction until I hear back.
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Jul 5, 2013 16:21
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ShadeofBlue posted:Torn flex PCB troubles. Good news, I fixed the torn flex cable! Well, I wired around it anyway. The first thing I did was to try a conductive pen, which of course failed completely. I know the thread told me not to bother trying, but I wanted to start with the least damaging method. I figured I would lose nothing by trying. It wasn't a total loss, because I figured out that it's not that hard to expose the copper in the cable. I scratched into it a bit with a knife, and then used one of the abrasive tools in a dremel kit (by hand, not with the dremel, obviously) to scrape away the top layer. After the pen failed (it just spread out too much, no matter how much I tried to mask things with tape or whatever), I decided to solder wires from wherever the copper track started, to across the tear. I staggered the solder points on the other side of the tear by cutting away bits of the flex cable. It actually wasn't too hard to solder everything, just time consuming since I was worried about melting the cable or burning out a component. I figure it might be smart to use something like epoxy on the solder joints to make them stronger. I can only assume that they will be pretty weak since the copper is so thin there. Does that make sense, and is there a particular brand or something that would be best to use? Thanks a bunch from everyone offering advice earlier. I also successfully clipped off the two contacts on the IC to complete the mod. The teleconverter focuses perfectly now .
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Jul 5, 2013 22:23
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Slanderer posted:The routing on that board is making me feel vaguely uncomfortable Yeah I'm getting a little mad looking at the bottom side. Does anyone know what exactly the wifi module part number is? If it's decent I might pick one up.
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Jul 6, 2013 02:11
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ShadeofBlue posted:Thanks a bunch from everyone offering advice earlier. I also successfully clipped off the two contacts on the IC to complete the mod. The teleconverter focuses perfectly now Good work! You have proven us naysayers wrong! Some sort of potting would definitely help for future reliability. Two part epoxy would work, surrounding the break and immobilizing your solder joint repairs against shock or vibration.
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Jul 6, 2013 02:31
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Martytoof posted:OSHpark: OSH park goes by square inches so you should not panelize, just order multiples and they will cut them out for you.
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Jul 8, 2013 02:23
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ANIME AKBAR posted:Yeah I'm getting a little mad looking at the bottom side. They do say it's "one of the earlier prototype boards" but no one should ever, ever do that, even on a prototype. Just reeks of laziness/autorouting/amateur-hour. Would not trust any of the analog performance on that thing from the ADCs/DACs. No idea why they didn't specify the WiFi part number...maybe it's that recent TI part, CC3000 IIRC?
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Jul 8, 2013 04:08
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