[TriEmbed] TriEmbed Digest, Vol 11, Issue 6

Carl Nobile carl.nobile at gmail.com
Fri Apr 4 19:42:02 CDT 2014


Chip,

I have never heard of shelf lives that short myself. I really cannot
believe that an microcontroller will go bad after 168 hrs.

As far as optics are concerned I have an assortment of eye pieces, my most
used one by far is a 14X eye piece.

As far as the caps are concerned get yourself a good digital multimeter,
most have capacitance meters built in.

Carl




On Fri, Apr 4, 2014 at 8:31 PM, Charles McClelland <chip at mcclellands.org>wrote:

> Pete, Carl and All,
>
> Thanks for your advice on this topic.  I wanted to take a look at the
> components and I have a couple more questions if I can:
>
> - Optics - My magnifying glass is not strong enough to read the marking
> clearly on the components.  I can make out some of the numbers (like 102
> which I assume means 10x10^2 on the 1k resistors) but it is tough.  I know
> Pete is not satisfied with the USB microscope he got from Adafruit but,
> what do you all use to inspect these parts?
>
> - Markings - not all the parts even have markings.  The capacitors do not
> seem to be marked at all leaving me to wonder how I can be sure of the part
> I am using.  Do I need something like this:
> https://www.sparkfun.com/products/10829
>
> - Shelf life - According to the markings on the bag, the ATMEGA328 SMD
> chips need to be installed within 168 hours of opening the bag.  Unless the
> approach Pete laid out below works, it seems I need to buy these chips as I
> need them which might get expensive.  The other humidity sensitive part -
> the LEDs - say they need to be installed within a week.  I had no idea
>  some of these parts had the shelf life of lettuce.  Is there a local
> supplier?
>
> Thanks again for putting up with my SMD-newbie questions.
>
> Chip
>
>
> On Apr 4, 2014, at 6:28 PM, triembed-request at triembed.org wrote:
>
> > Send TriEmbed mailing list submissions to
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> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of TriEmbed digest..."
> >
> >
> > Today's Topics:
> >
> >   1. Surface Mount Components Newbie Questions (Charles McClelland)
> >   2. Fwd:  Surface Mount Components Newbie Questions (Carl Nobile)
> >   3. Re: Surface Mount Components Newbie Questions (Carl Nobile)
> >   4. Re: Surface Mount Components Newbie Questions (Pete Soper)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Fri, 4 Apr 2014 16:38:32 -0400
> > From: Charles McClelland <chip at mcclellands.org>
> > To: TriEmbed Discussion <triembed at triembed.org>
> > Subject: [TriEmbed] Surface Mount Components Newbie Questions
> > Message-ID: <9D001F91-9195-4A64-AD0C-B360E3836CEF at mcclellands.org>
> > Content-Type: text/plain; charset=us-ascii
> >
> > Hey all,
> >
> > I am gearing up for my first surface mount project.  OSH Park has just
> told me the boards are in the mail and DigiKey just sent me the bill of
> materials.  I have some questions now that I have opened the box from
> DigiKey:
> >
> > 1) Some of the components claim to be humidity sensitive.  Is this a big
> deal for hobby use?  Do I need to keep these in a sealed bag with desiccant
> or is that overkill?
> >
> > 2) Some of the components claim to be sensitive to electrostatic
> discharge.  I have yet to fry a through hold component - are surface mount
> components more sensitive?
> >
> > 3) The components come on tape which will be inefficient to store using
> the cool storage boxes Pete showed me.  Is there anything wrong with
> removing the parts from the tape?
> >
> > I went with 0805 components so nothing is microscopic.
> >
> > Thanks,
> >
> > Chip
> >
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Fri, 4 Apr 2014 16:55:57 -0400
> > From: Carl Nobile <carl.nobile at gmail.com>
> > To: TriEmbed <TriEmbed at triembed.org>
> > Subject: [TriEmbed] Fwd:  Surface Mount Components Newbie Questions
> > Message-ID:
> >       <CAGQqDQKgkOYCM0U6sC7ynUsT6ykGEVjX6wz=
> eh71CFDLDkEU2g at mail.gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Sorry I sent this to Chip and forgot to click all.
> >
> > Chip,
> >
> > The static issue is the one to be very careful about. If you walk on a
> > staticky rug then touch a component, say good by to the component. At the
> > point where you can feel a shock it is already way too high and will blow
> > any static sensitive component. They must be kept in one of those dark
> gray
> > static bags. DO NOT use the pink ones, they're useless.
> >
> > BTW, components do not know if you are a hobbyist or a professional, if
> the
> > component doesn't like the humidity it will be damaged in either case.
> >
> > I always keep most parts in sealed plastic bags. If static electricity is
> > not an issue, like with resistors and capacitors, you can use clear
> plastic
> > bags. I get them at hobby stores, they come in all the right sizes and
> are
> > pretty cheap.
> >
> > Carl
> >
> >
> >
> > On Fri, Apr 4, 2014 at 4:38 PM, Charles McClelland <chip at mcclellands.org
> >wrote:
> >
> >> Hey all,
> >>
> >> I am gearing up for my first surface mount project.  OSH Park has just
> >> told me the boards are in the mail and DigiKey just sent me the bill of
> >> materials.  I have some questions now that I have opened the box from
> >> DigiKey:
> >>
> >> 1) Some of the components claim to be humidity sensitive.  Is this a big
> >> deal for hobby use?  Do I need to keep these in a sealed bag with
> desiccant
> >> or is that overkill?
> >>
> >> 2) Some of the components claim to be sensitive to electrostatic
> >> discharge.  I have yet to fry a through hold component - are surface
> mount
> >> components more sensitive?
> >>
> >> 3) The components come on tape which will be inefficient to store using
> >> the cool storage boxes Pete showed me.  Is there anything wrong with
> >> removing the parts from the tape?
> >>
> >> I went with 0805 components so nothing is microscopic.
> >>
> >> Thanks,
> >>
> >> Chip
> >>
> >>
> >>
> >> _______________________________________________
> >> Triangle, NC Embedded Computing mailing list
> >> TriEmbed at triembed.org
> >> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> >> TriEmbed web site: http://TriEmbed.org
> >>
> >
> >
> >
> > --
> >
> -------------------------------------------------------------------------------
> > Carl J. Nobile (Software Engineer)
> > carl.nobile at gmail.com
> >
> -------------------------------------------------------------------------------
> >
> >
> >
> >
> > --
> >
> -------------------------------------------------------------------------------
> > Carl J. Nobile (Software Engineer)
> > carl.nobile at gmail.com
> >
> -------------------------------------------------------------------------------
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
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> http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20140404/ac4b06d5/attachment-0001.html
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Fri, 4 Apr 2014 17:31:48 -0400
> > From: Carl Nobile <carl.nobile at gmail.com>
> > To: Charles McClelland <chip at mcclellands.org>, TriEmbed
> >       <TriEmbed at triembed.org>
> > Subject: Re: [TriEmbed] Surface Mount Components Newbie Questions
> > Message-ID:
> >       <CAGQqDQ+8g=
> uXYw7s-9pgBBMcwZ66Fp7y4ZFNs0UV0gBFGUWfpA at mail.gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Chip,
> >
> > You have a point about the automated machines, if the humidity is high
> the
> > machines may malfunction. However, I do know of components that have
> > humidity issues also like some capacitors. It is not the water itself
> > which, by-the-way, will not conduct electricity, it's the impurities in
> the
> > water that is the issue. Humidity can change a crystal's frequency. When
> I
> > used to work on transmitters the oscillators were put into a heated box
> so
> > the radio/TV station would not drift off frequency. An FCC pink slip
> would
> > show up in the stations mail box with a hefty fine attached if the
> station
> > frequency did drift.
> >
> > I usually leave the parts on the ribbon tape and fold them up and put
> them
> > in a bag. Too much work taking them all apart and getting them mixed up
> > with other like parts.
> >
> > Carl
> >
> >
> >
> > On Fri, Apr 4, 2014 at 5:14 PM, Charles McClelland <chip at mcclellands.org
> >wrote:
> >
> >> Carl,
> >>
> >> Thanks, I guess I do need to think about static.  I also like you
> plastic
> >> bag idea.
> >>
> >> On your point about hobbits or professional, let me explain what I was
> >> thinking.   I assume that the reason many of these components are sold
> as
> >> cut tape is to accommodate the hobbyist who wants to order just a few.
> >> However, I am assuming that these same components are sold in entire
> reels
> >> of tape to the professional who might use an automated machine to place
> >> them on a board as part of a production line process.  I guess I was
> >> wondering if it was the performance of these components in one of these
> >> automated production lines where humidity is an issue.  Otherwise, will
> >> that sensitivity to humidity be an issue for the component on the
> assembled
> >> board?
> >>
> >> Thanks,
> >>
> >> Chip
> >>
> >>
> >> On Apr 4, 2014, at 4:51 PM, Carl Nobile <carl.nobile at gmail.com> wrote:
> >>
> >> Chip,
> >>
> >> The static issue is the one to be very careful about. If you walk on a
> >> staticky rug then touch a component, say good by to the component. At
> the
> >> point where you can feel a shock it is already way too high and will
> blow
> >> any static sensitive component. They must be kept in one of those dark
> gray
> >> static bags. DO NOT use the pink ones, they're useless.
> >>
> >> BTW, components do not know if you are a hobbyist or a professional, if
> >> the component doesn't like the humidity it will be damaged in either
> case.
> >>
> >> I always keep most parts in sealed plastic bags. If static electricity
> is
> >> not an issue, like with resistors and capacitors, you can use clear
> plastic
> >> bags. I get them at hobby stores, they come in all the right sizes and
> are
> >> pretty cheap.
> >>
> >> Carl
> >>
> >>
> >>
> >> On Fri, Apr 4, 2014 at 4:38 PM, Charles McClelland <
> chip at mcclellands.org>wrote:
> >>
> >>> Hey all,
> >>>
> >>> I am gearing up for my first surface mount project.  OSH Park has just
> >>> told me the boards are in the mail and DigiKey just sent me the bill of
> >>> materials.  I have some questions now that I have opened the box from
> >>> DigiKey:
> >>>
> >>> 1) Some of the components claim to be humidity sensitive.  Is this a
> big
> >>> deal for hobby use?  Do I need to keep these in a sealed bag with
> desiccant
> >>> or is that overkill?
> >>>
> >>> 2) Some of the components claim to be sensitive to electrostatic
> >>> discharge.  I have yet to fry a through hold component - are surface
> mount
> >>> components more sensitive?
> >>>
> >>> 3) The components come on tape which will be inefficient to store using
> >>> the cool storage boxes Pete showed me.  Is there anything wrong with
> >>> removing the parts from the tape?
> >>>
> >>> I went with 0805 components so nothing is microscopic.
> >>>
> >>> Thanks,
> >>>
> >>> Chip
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> Triangle, NC Embedded Computing mailing list
> >>> TriEmbed at triembed.org
> >>> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> >>> TriEmbed web site: http://TriEmbed.org <http://triembed.org/>
> >>>
> >>
> >>
> >>
> >> --
> >>
> >>
> -------------------------------------------------------------------------------
> >> Carl J. Nobile (Software Engineer)
> >> carl.nobile at gmail.com
> >>
> -------------------------------------------------------------------------------
> >>
> >>
> >>
> >>
> >
> >
> > --
> >
> -------------------------------------------------------------------------------
> > Carl J. Nobile (Software Engineer)
> > carl.nobile at gmail.com
> >
> -------------------------------------------------------------------------------
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
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> >
> >
> > ------------------------------
> >
> > Message: 4
> > Date: Fri, 04 Apr 2014 18:28:33 -0400
> > From: Pete Soper <pete at soper.us>
> > To: triembed at triembed.org
> > Subject: Re: [TriEmbed] Surface Mount Components Newbie Questions
> > Message-ID: <533F3211.8000906 at soper.us>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > I leave those chips in their bags. Inside with the chips are bags of
> > desiccants. I'm told that the basic issue is that if the chip absorbs
> > much moisture then when it goes through the reflow oven it can
> > "popcorn." I don't need to describe what that means. I leave chips like
> > this in the bags, then when I'm going to use a fraction of them I put
> > the remainder with the desiccant bags into airtight containers with the
> > humidity test strips. This may be overkill.
> >
> > And as I type this I'm about to test out the low tech hood and vent
> > system for my oven. This is a very small oven and I have a very powerful
> > fan pushing air out of the basement, so hopefully I won't have to run
> > the oven outdoors in the near future.
> > -Pete
> >
> > On 04/04/2014 04:38 PM, Charles McClelland wrote:
> >> Hey all,
> >>
> >> I am gearing up for my first surface mount project.  OSH Park has just
> told me the boards are in the mail and DigiKey just sent me the bill of
> materials.  I have some questions now that I have opened the box from
> DigiKey:
> >>
> >> 1) Some of the components claim to be humidity sensitive.  Is this a
> big deal for hobby use?  Do I need to keep these in a sealed bag with
> desiccant or is that overkill?
> >>
> >> 2) Some of the components claim to be sensitive to electrostatic
> discharge.  I have yet to fry a through hold component - are surface mount
> components more sensitive?
> >>
> >> 3) The components come on tape which will be inefficient to store using
> the cool storage boxes Pete showed me.  Is there anything wrong with
> removing the parts from the tape?
> >>
> >> I went with 0805 components so nothing is microscopic.
> >>
> >> Thanks,
> >>
> >> Chip
> >>
> >>
> >>
> >> _______________________________________________
> >> Triangle, NC Embedded Computing mailing list
> >> TriEmbed at triembed.org
> >> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> >> TriEmbed web site: http://TriEmbed.org
> >
> >
> >
> >
> > ------------------------------
> >
> > Subject: Digest Footer
> >
> > _______________________________________________
> > TriEmbed mailing list
> > TriEmbed at triembed.org
> > http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> >
> >
> > ------------------------------
> >
> > End of TriEmbed Digest, Vol 11, Issue 6
> > ***************************************
>
>
> _______________________________________________
> Triangle, NC Embedded Computing mailing list
> TriEmbed at triembed.org
> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org
> TriEmbed web site: http://TriEmbed.org
>



-- 
-------------------------------------------------------------------------------
Carl J. Nobile (Software Engineer)
carl.nobile at gmail.com
-------------------------------------------------------------------------------
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