New run of orbshields

SpaceOrb drivers and software discussions
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VDX
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Joined: February 12 2013, 16:47 PM

Re: New run of orbshields

Postby VDX » May 02 2013, 4:55 AM

[quote="vputz"]You'd have to flash the chip yourself, though.[/quote]

... I have a JTAG (two-wire) adapter with 10pin-header and maybe a 6-pin converter too - but your 6-pin header seems to be only ISP, no JTAG?



Have an older ISP from another AVR-bot project too, will check, if it's working with the Arduino-IDE ...



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vputz
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Re: New run of orbshields

Postby vputz » May 02 2013, 5:03 AM

Yeah, the 6-pin header is ISP only. The UsbTinyISP project was simple enough I understood it, and full JTAG support was confusing at the time (I'm starting to learn as I can see the writing on the wall for moving toward ARM). I'm not sure how well the AVRs support JTAG to be honest (although I did find TAP pins for boundary scan as mentioned...) Additionally the Arduino IDE supports several ISP boards in addition to the USB interface, and I wanted the devices to be easily reflashed by the home user if somehow the bootloader got corrupted.



Now this "revision 2" of the SMD is occupying me, and I haven't even gotten rev1 out the door. I think basically I need to set up the mill again, if only to test footprints and make small breakout boards. I don't know that I can convince it to be accurate enough for QFP, but even if I go back to etching (or using the laser trick) it may at least foster that fast turnaround that's so nice for prototyping.

VDX
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Re: New run of orbshields

Postby VDX » May 02 2013, 6:39 AM

... my mill is accurate to 12.5 microns per step and the spindle with 22000rpm fast enough for finepitch-engraving with carbide bits ... only my time-scheduling is problematic :? -- otherwise I'll offer to mill som double-sided prototypes for testing ...



Later this summer I'll build a much more precise machine and attach an engraving/cutting fiber-laser to the toolhead -- then the limits would be somewhere at 10microns wide grooves and 2microns accuracy ... or even finer - the linear drives have 0.5microns resolution and the fiberlaser can be reduced to 5microns spot-size :wink:



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kenyee
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Joined: April 02 2013, 8:33 AM

Re: New run of orbshields

Postby kenyee » May 02 2013, 10:07 AM

[quote="vputz"]
Kenyee: Actually as it turns out the footprint I used didn't have solder mask, so I can't blame the PCB folks. But this was the footprint adapted from Adafruit's 32u4 breakout board, so I'm going to ask if they really don't have solder mask on their 32u4 chips.
[/quote]


? AFAIK, footprints don't include solder masks. They only define footprints, outlines, and keepout areas for routing.

Maybe the design rules you loaded for the board layout were a bit too safe?

In EagleCAD, there are also 44 pin TQFP ATMEGA32 parts in the Atmel cadsoft library and in the Sparkfun library. The Sparkfun library doesn't have keepout areas defined so if you really think the solder mask is in the footprint, you might want to try that.



I read up a bit more on usb connectors and apparently mini-usb has the least # of insertions before failure :|

Microusb has the most, but it's prone to ripping off the board :D



Still can't believe they designed the microusb footprint like that.

Did another dig for usable parts and found this one from FCI:

http://www.digikey.com/product-detail/en/10103593-0001LF/609-4049-1-ND/2350356

http://portal.fciconnect.com/Comergent//fci/drawing/10103593.pdf

At least they added a shield notch so you can see the damned pins from above. I don't know what the manufacturers of these parts are thinking :roll:

There are also a few different through hole micro-usb parts, but they're all stand-up parts (90 degrees to board)....nothing parallel to the board. They'd be a lot easier to solder and work with obviously.

vputz
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Re: New run of orbshields

Postby vputz » May 02 2013, 17:17 PM

[quote="kenyee"]
? AFAIK, footprints don't include solder masks.
[/quote]


Fair point (I wasn't sure; never mistake me for someone who knows what I'm doing so much as someone who just doesn't know when he's beat...). The design rules I have are probably overly conservative since I set them to be very safe based on my mill.


[quote]
I read up a bit more on usb connectors and apparently mini-usb has the least # of insertions before failure :|

Microusb has the most, but it's prone to ripping off the board :D
[/quote]


Yep; mini-usb is deprecated so everything uses micro these days--that's why I was looking for one that had holes and pins--would help with insertion strain, but still not twisting. If I could get the case spacers exactly right, that would help a bit, but I'd need to shave about half a mm off... there is a "straddle" version that goes on both sides of the board, but would require a little more intervention (no hot plate!) so I'm not sold yet.



VDX: sounds like a sweet mill setup all right! Mine's a really junky kit using plain old allthread for linear bearings--not even acme leadscrews much less anything more refined. It's a miracle it works at all, but it was a good intro. I haven't been able to justify the cost of upgrading it, though...

kenyee
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Re: New run of orbshields

Postby kenyee » May 03 2013, 8:19 AM

[quote="vputz"]
The design rules I have are probably overly conservative since I set them to be very safe based on my mill.

...

there is a "straddle" version that goes on both sides of the board, but would require a little more intervention (no hot plate!) so I'm not sold yet.[/quote]


FWIW, I've used SparkFun's DRu file w/o issues at oshpark. Might be worth running the CAM job w/ it just to see if that helps and then load it into viewplot to see if a solder mask shows up on that TQFP part:

https://github.com/zacinaction/kicksat/blob/master/Sprite/EagleCAD/Sprite/dru/SparkFun.dru

http://hackaday.com/2009/01/15/how-to-prepare-your-eagle-designs-for-manufacture/

You're going to have a lot of pain w/o a solder mask on fine pitched parts... :(



I saw the mid-board version when I looked as well, but it looked like a pain because it needed a special cutout on the board as well as hand placement/soldering.

I ordered the FCI microusb part (it was only $1) w/ an order of parts for my project so I can get a better look at it to see how solderable it is. It's probably the best of the surface mount ones I've seen so far. Everything else seems stupidly buried under the shield/case :evil:

vputz
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Re: New run of orbshields

Postby vputz » May 03 2013, 14:02 PM

It's interesting, because web searching has shown a lot of forum threads about how solder-mask on fine pitches is LESS useful and a lot of people don't seem to recommend it! Not what I expected. More research to be done...

kenyee
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Re: New run of orbshields

Postby kenyee » May 03 2013, 21:01 PM

[quote="vputz"]It's interesting, because web searching has shown a lot of forum threads about how solder-mask on fine pitches is LESS useful and a lot of people don't seem to recommend it! Not what I expected. More research to be done...[/quote]

Not from a quick dig.

Apparently, the sparkfun QFN part is broken and has no solder mask:

https://forum.sparkfun.com/viewtopic.php?f=20&t=32027

There's a comment about failure rate w/o a solder mask too.



And another comment about how no solder mask = bridges = boards suck :)

http://dangerousprototypes.com/2011/10/13/is-soldermask-required-for-fine-pitch-ic-soldering/

kenyee
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Re: New run of orbshields

Postby kenyee » May 04 2013, 20:53 PM

[quote="kenyee"]
I ordered the FCI microusb part (it was only $1) w/ an order of parts for my project so I can get a better look at it to see how solderable it is. It's probably the best of the surface mount ones I've seen so far. Everything else seems stupidly buried under the shield/case :evil:[/quote]


FYI, this isn't too bad. The two ground pins are barely visible, but the main pins are fairly visible. Some flux and drag soldering away from the case should make it relatively easy to solder.

Still a far cry from the vertical through hole ones though, which should be trivial :)

vputz
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Re: New run of orbshields

Postby vputz » May 17 2013, 8:02 AM

Well, the boards are in town... but I can't get them yet. Evidently they triggered import and customs charges... equal to the amount I paid for the boards. AND equal to the amount I paid for "rush shipping". So much for cheap overseas production; I would have been better off using my local guys after all. Maybe. Sigh. Anyway, since it would cost another decent charge to get them delivered on Saturday, I requested them for my next work-from-home day, Thursday.



So anyway, next weekend will likely be a build weekend and maybe by then a few more folks will have their boards and I can have the store tested for the first round of orders.



Really sorry for the delays, folks.

kenyee
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Re: New run of orbshields

Postby kenyee » May 22 2013, 9:58 AM

[quote="vputz"] Evidently they triggered import and customs charges... equal to the amount I paid for the boards. AND equal to the amount I paid for "rush shipping".[/quote]

Ouch. Too bad they didn't mark them as "gift". That usually works to avoid customs/import charges.



Got my SMD guinea pig version. Dum question, but where do you get the driver to install? The orbotron github page says you have to install it weirdly because of the unsigned driver in Win8 but doesn't say where to get it :)



Checked the solder mask and it looks ok between the atmel chip pins. You shouldn't be getting solder bridges.

Your microusb jack is definitely the usual PITA variety where the stupid pins are buried under the damned shell and PCB. Look at the one I linked to above for something that's a little easier to get at the pins (still sucks but it's better than this)-:



Love the case design w/ the cutout. You might want to round the case lexan and the PCB on the DB9 end. Maybe cut the height of the bottom spacers (but this would mean stocking yet another part so no real need to do it if that's a PITA).

vputz
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Re: New run of orbshields

Postby vputz » May 22 2013, 10:25 AM

Not a dumb question about the driver. You don't actually need a driver for it to work like a HID device, just to use the Arduino environment and reprogram it--but that's the answer actually. Point it at the .inf file in the hardware/orbotron directory.



Now, one thing I can't check is if the .inf is all you need or if it relies on the driver in the Arduino distribution (that directory is meant to be put in the Arduino installation). So check that :)



The bottom spacer height is worth considering; the only problem is then it triggers a search for different-length screws... point taken about the pcb/case rounding on the DB9 end, but both of these will have to wait until I sell the first batch (I have a tentative design for an even smaller version, same schematic--but it's probably time to get these out and look at other projects for a bit). Going to learn about bluetooth and ARM SOICs. Never know; you may face a cordless bluetooth spaceorb someday... :lol:

vputz
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Re: New run of orbshields

Postby vputz » May 23 2013, 4:38 AM

[attachment=0]boards.jpg[/attachment]
:D
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VDX
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Re: New run of orbshields

Postby VDX » May 23 2013, 4:44 AM

... nice! - which is mine? :wink:



Viktor

vputz
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Re: New run of orbshields

Postby vputz » May 23 2013, 9:45 AM

I'll tell you after this weekend (there's still a chance these don't work; I added a couple of testing ports since the last revision, which is funny because I may not even use them since no one seems to be able to tell me why my boundary scan isn't working). I'm going to build a handful and then save the rest and see if I can teach a SMD stencil class at the local hackspace (if they want a board, they can buy it cheap, and if not I get minions to help assemble :) I'll have some rework, but then I do when I do it too.



And speaking of rework...


[attachment=0]hot_air.jpg[/attachment]

Oh, I know, it's cheap and will probably catch fire or shock me, but I wanted to try a hot air rework setup and see what it helps with. The blowtorch... was a bad idea. Lesson learned.
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