<div dir="ltr">Chip,<div><br></div><div>I have never heard of shelf lives that short myself. I really cannot believe that an microcontroller will go bad after 168 hrs.</div><div><br></div><div>As far as optics are concerned I have an assortment of eye pieces, my most used one by far is a 14X eye piece.</div>
<div><br></div><div>As far as the caps are concerned get yourself a good digital multimeter, most have capacitance meters built in.</div><div><br></div><div>Carl</div><div><br></div><div><br></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Fri, Apr 4, 2014 at 8:31 PM, Charles McClelland <span dir="ltr"><<a href="mailto:chip@mcclellands.org" target="_blank">chip@mcclellands.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Pete, Carl and All,<br>
<br>
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:<br>
<br>
- 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?<br>
<br>
- 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: <a href="https://www.sparkfun.com/products/10829" target="_blank">https://www.sparkfun.com/products/10829</a><br>
<br>
- 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?<br>
<br>
Thanks again for putting up with my SMD-newbie questions.<br>
<br>
Chip<br>
<br>
<br>
On Apr 4, 2014, at 6:28 PM, <a href="mailto:triembed-request@triembed.org">triembed-request@triembed.org</a> wrote:<br>
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> Today's Topics:<br>
><br>
> 1. Surface Mount Components Newbie Questions (Charles McClelland)<br>
> 2. Fwd: Surface Mount Components Newbie Questions (Carl Nobile)<br>
> 3. Re: Surface Mount Components Newbie Questions (Carl Nobile)<br>
> 4. Re: Surface Mount Components Newbie Questions (Pete Soper)<br>
><br>
><br>
> ----------------------------------------------------------------------<br>
><br>
> Message: 1<br>
> Date: Fri, 4 Apr 2014 16:38:32 -0400<br>
> From: Charles McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>><br>
> To: TriEmbed Discussion <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>><br>
> Subject: [TriEmbed] Surface Mount Components Newbie Questions<br>
> Message-ID: <<a href="mailto:9D001F91-9195-4A64-AD0C-B360E3836CEF@mcclellands.org">9D001F91-9195-4A64-AD0C-B360E3836CEF@mcclellands.org</a>><br>
> Content-Type: text/plain; charset=us-ascii<br>
><br>
> Hey all,<br>
><br>
> 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:<br>
><br>
> 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?<br>
><br>
> 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?<br>
><br>
> 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?<br>
><br>
> I went with 0805 components so nothing is microscopic.<br>
><br>
> Thanks,<br>
><br>
> Chip<br>
><br>
><br>
><br>
><br>
><br>
> ------------------------------<br>
><br>
> Message: 2<br>
> Date: Fri, 4 Apr 2014 16:55:57 -0400<br>
> From: Carl Nobile <<a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a>><br>
> To: TriEmbed <<a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a>><br>
> Subject: [TriEmbed] Fwd: Surface Mount Components Newbie Questions<br>
> Message-ID:<br>
> <CAGQqDQKgkOYCM0U6sC7ynUsT6ykGEVjX6wz=<a href="mailto:eh71CFDLDkEU2g@mail.gmail.com">eh71CFDLDkEU2g@mail.gmail.com</a>><br>
> Content-Type: text/plain; charset="utf-8"<br>
><br>
> Sorry I sent this to Chip and forgot to click all.<br>
><br>
> Chip,<br>
><br>
> The static issue is the one to be very careful about. If you walk on a<br>
> staticky rug then touch a component, say good by to the component. At the<br>
> point where you can feel a shock it is already way too high and will blow<br>
> any static sensitive component. They must be kept in one of those dark gray<br>
> static bags. DO NOT use the pink ones, they're useless.<br>
><br>
> BTW, components do not know if you are a hobbyist or a professional, if the<br>
> component doesn't like the humidity it will be damaged in either case.<br>
><br>
> I always keep most parts in sealed plastic bags. If static electricity is<br>
> not an issue, like with resistors and capacitors, you can use clear plastic<br>
> bags. I get them at hobby stores, they come in all the right sizes and are<br>
> pretty cheap.<br>
><br>
> Carl<br>
><br>
><br>
><br>
> On Fri, Apr 4, 2014 at 4:38 PM, Charles McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>>wrote:<br>
><br>
>> Hey all,<br>
>><br>
>> I am gearing up for my first surface mount project. OSH Park has just<br>
>> told me the boards are in the mail and DigiKey just sent me the bill of<br>
>> materials. I have some questions now that I have opened the box from<br>
>> DigiKey:<br>
>><br>
>> 1) Some of the components claim to be humidity sensitive. Is this a big<br>
>> deal for hobby use? Do I need to keep these in a sealed bag with desiccant<br>
>> or is that overkill?<br>
>><br>
>> 2) Some of the components claim to be sensitive to electrostatic<br>
>> discharge. I have yet to fry a through hold component - are surface mount<br>
>> components more sensitive?<br>
>><br>
>> 3) The components come on tape which will be inefficient to store using<br>
>> the cool storage boxes Pete showed me. Is there anything wrong with<br>
>> removing the parts from the tape?<br>
>><br>
>> I went with 0805 components so nothing is microscopic.<br>
>><br>
>> Thanks,<br>
>><br>
>> Chip<br>
>><br>
>><br>
>><br>
>> _______________________________________________<br>
>> Triangle, NC Embedded Computing mailing list<br>
>> <a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>
>> <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>
>> TriEmbed web site: <a href="http://TriEmbed.org" target="_blank">http://TriEmbed.org</a><br>
>><br>
><br>
><br>
><br>
> --<br>
> -------------------------------------------------------------------------------<br>
> Carl J. Nobile (Software Engineer)<br>
> <a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a><br>
> -------------------------------------------------------------------------------<br>
><br>
><br>
><br>
><br>
> --<br>
> -------------------------------------------------------------------------------<br>
> Carl J. Nobile (Software Engineer)<br>
> <a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a><br>
> -------------------------------------------------------------------------------<br>
> -------------- next part --------------<br>
> An HTML attachment was scrubbed...<br>
> URL: <<a href="http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20140404/ac4b06d5/attachment-0001.html" target="_blank">http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20140404/ac4b06d5/attachment-0001.html</a>><br>
><br>
> ------------------------------<br>
><br>
> Message: 3<br>
> Date: Fri, 4 Apr 2014 17:31:48 -0400<br>
> From: Carl Nobile <<a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a>><br>
> To: Charles McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>>, TriEmbed<br>
> <<a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a>><br>
> Subject: Re: [TriEmbed] Surface Mount Components Newbie Questions<br>
> Message-ID:<br>
> <CAGQqDQ+8g=<a href="mailto:uXYw7s-9pgBBMcwZ66Fp7y4ZFNs0UV0gBFGUWfpA@mail.gmail.com">uXYw7s-9pgBBMcwZ66Fp7y4ZFNs0UV0gBFGUWfpA@mail.gmail.com</a>><br>
> Content-Type: text/plain; charset="utf-8"<br>
><br>
> Chip,<br>
><br>
> You have a point about the automated machines, if the humidity is high the<br>
> machines may malfunction. However, I do know of components that have<br>
> humidity issues also like some capacitors. It is not the water itself<br>
> which, by-the-way, will not conduct electricity, it's the impurities in the<br>
> water that is the issue. Humidity can change a crystal's frequency. When I<br>
> used to work on transmitters the oscillators were put into a heated box so<br>
> the radio/TV station would not drift off frequency. An FCC pink slip would<br>
> show up in the stations mail box with a hefty fine attached if the station<br>
> frequency did drift.<br>
><br>
> I usually leave the parts on the ribbon tape and fold them up and put them<br>
> in a bag. Too much work taking them all apart and getting them mixed up<br>
> with other like parts.<br>
><br>
> Carl<br>
><br>
><br>
><br>
> On Fri, Apr 4, 2014 at 5:14 PM, Charles McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>>wrote:<br>
><br>
>> Carl,<br>
>><br>
>> Thanks, I guess I do need to think about static. I also like you plastic<br>
>> bag idea.<br>
>><br>
>> On your point about hobbits or professional, let me explain what I was<br>
>> thinking. I assume that the reason many of these components are sold as<br>
>> cut tape is to accommodate the hobbyist who wants to order just a few.<br>
>> However, I am assuming that these same components are sold in entire reels<br>
>> of tape to the professional who might use an automated machine to place<br>
>> them on a board as part of a production line process. I guess I was<br>
>> wondering if it was the performance of these components in one of these<br>
>> automated production lines where humidity is an issue. Otherwise, will<br>
>> that sensitivity to humidity be an issue for the component on the assembled<br>
>> board?<br>
>><br>
>> Thanks,<br>
>><br>
>> Chip<br>
>><br>
>><br>
>> On Apr 4, 2014, at 4:51 PM, Carl Nobile <<a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a>> wrote:<br>
>><br>
>> Chip,<br>
>><br>
>> The static issue is the one to be very careful about. If you walk on a<br>
>> staticky rug then touch a component, say good by to the component. At the<br>
>> point where you can feel a shock it is already way too high and will blow<br>
>> any static sensitive component. They must be kept in one of those dark gray<br>
>> static bags. DO NOT use the pink ones, they're useless.<br>
>><br>
>> BTW, components do not know if you are a hobbyist or a professional, if<br>
>> the component doesn't like the humidity it will be damaged in either case.<br>
>><br>
>> I always keep most parts in sealed plastic bags. If static electricity is<br>
>> not an issue, like with resistors and capacitors, you can use clear plastic<br>
>> bags. I get them at hobby stores, they come in all the right sizes and are<br>
>> pretty cheap.<br>
>><br>
>> Carl<br>
>><br>
>><br>
>><br>
>> On Fri, Apr 4, 2014 at 4:38 PM, Charles McClelland <<a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a>>wrote:<br>
>><br>
>>> Hey all,<br>
>>><br>
>>> I am gearing up for my first surface mount project. OSH Park has just<br>
>>> told me the boards are in the mail and DigiKey just sent me the bill of<br>
>>> materials. I have some questions now that I have opened the box from<br>
>>> DigiKey:<br>
>>><br>
>>> 1) Some of the components claim to be humidity sensitive. Is this a big<br>
>>> deal for hobby use? Do I need to keep these in a sealed bag with desiccant<br>
>>> or is that overkill?<br>
>>><br>
>>> 2) Some of the components claim to be sensitive to electrostatic<br>
>>> discharge. I have yet to fry a through hold component - are surface mount<br>
>>> components more sensitive?<br>
>>><br>
>>> 3) The components come on tape which will be inefficient to store using<br>
>>> the cool storage boxes Pete showed me. Is there anything wrong with<br>
>>> removing the parts from the tape?<br>
>>><br>
>>> I went with 0805 components so nothing is microscopic.<br>
>>><br>
>>> Thanks,<br>
>>><br>
>>> Chip<br>
>>><br>
>>><br>
>>><br>
>>> _______________________________________________<br>
>>> Triangle, NC Embedded Computing mailing list<br>
>>> <a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>
>>> <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>
>>> TriEmbed web site: <a href="http://TriEmbed.org" target="_blank">http://TriEmbed.org</a> <<a href="http://triembed.org/" target="_blank">http://triembed.org/</a>><br>
>>><br>
>><br>
>><br>
>><br>
>> --<br>
>><br>
>> -------------------------------------------------------------------------------<br>
>> Carl J. Nobile (Software Engineer)<br>
>> <a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a><br>
>> -------------------------------------------------------------------------------<br>
>><br>
>><br>
>><br>
>><br>
><br>
><br>
> --<br>
> -------------------------------------------------------------------------------<br>
> Carl J. Nobile (Software Engineer)<br>
> <a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a><br>
> -------------------------------------------------------------------------------<br>
> -------------- next part --------------<br>
> An HTML attachment was scrubbed...<br>
> URL: <<a href="http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20140404/b42fbaee/attachment-0001.html" target="_blank">http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20140404/b42fbaee/attachment-0001.html</a>><br>
><br>
> ------------------------------<br>
><br>
> Message: 4<br>
> Date: Fri, 04 Apr 2014 18:28:33 -0400<br>
> From: Pete Soper <<a href="mailto:pete@soper.us">pete@soper.us</a>><br>
> To: <a href="mailto:triembed@triembed.org">triembed@triembed.org</a><br>
> Subject: Re: [TriEmbed] Surface Mount Components Newbie Questions<br>
> Message-ID: <<a href="mailto:533F3211.8000906@soper.us">533F3211.8000906@soper.us</a>><br>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed<br>
><br>
> I leave those chips in their bags. Inside with the chips are bags of<br>
> desiccants. I'm told that the basic issue is that if the chip absorbs<br>
> much moisture then when it goes through the reflow oven it can<br>
> "popcorn." I don't need to describe what that means. I leave chips like<br>
> this in the bags, then when I'm going to use a fraction of them I put<br>
> the remainder with the desiccant bags into airtight containers with the<br>
> humidity test strips. This may be overkill.<br>
><br>
> And as I type this I'm about to test out the low tech hood and vent<br>
> system for my oven. This is a very small oven and I have a very powerful<br>
> fan pushing air out of the basement, so hopefully I won't have to run<br>
> the oven outdoors in the near future.<br>
> -Pete<br>
><br>
> On 04/04/2014 04:38 PM, Charles McClelland wrote:<br>
>> Hey all,<br>
>><br>
>> 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:<br>
>><br>
>> 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?<br>
>><br>
>> 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?<br>
>><br>
>> 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?<br>
>><br>
>> I went with 0805 components so nothing is microscopic.<br>
>><br>
>> Thanks,<br>
>><br>
>> Chip<br>
>><br>
>><br>
>><br>
>> _______________________________________________<br>
>> Triangle, NC Embedded Computing mailing list<br>
>> <a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>
>> <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>
>> TriEmbed web site: <a href="http://TriEmbed.org" target="_blank">http://TriEmbed.org</a><br>
><br>
><br>
><br>
><br>
> ------------------------------<br>
><br>
> Subject: Digest Footer<br>
><br>
> _______________________________________________<br>
> TriEmbed mailing list<br>
> <a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>
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><br>
><br>
> ------------------------------<br>
><br>
> End of TriEmbed Digest, Vol 11, Issue 6<br>
> ***************************************<br>
<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br>-------------------------------------------------------------------------------<br>Carl J. Nobile (Software Engineer)<br><a href="mailto:carl.nobile@gmail.com">carl.nobile@gmail.com</a><br>
-------------------------------------------------------------------------------
</div>