[time-nuts] Parts Selection

[Chris Albertson]

Would I take on a project with those parts?   Maybe but eBay places an
upper limit on what I'll spend to build something.  I'd much rather
buy a used HP counter for $250 than spend $500 to build one.  You'd
have to get the build cost to less than 1/2 the buy cost.

0.5 mm is not that hard to hand solder if you have the right equipment
and optical magnification but with a 100 pin part it would take a long
time and there is the risk of damaging an expensive part.    Better I
think to find someone with a re-flow oven

Or for project to be built in small number of under 50 or so you can
base the project on some kind of FPGA development board that can be
bought off the shelf preassembled.   There are many of these just as
an example look at this one

http://www.gadgetfactory.net/index.php?main_page=product_info&cPath=1&products_id=18


On Fri, Mar 25, 2011 at 10:07 AM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
>
>
> Just a show of hands sort of thing. It comes up each time we talk about
> projects and never really gets answered. Rather than trying to work it out
> as a part of a project, let's see if it can be addressed by it's self.
>
>
>
> How many people are willing to solder up a project with multiple 0.5mm
> spacing >=144 pin package IC's on it? There's a typical package drawing at
> the end of:
>
>
>
> http://www.national.com/ds/DP/DP83816EX.pdf
>
>
>
> I'm sure it's a "what's in it for me?" sort of question. Let's assume it's
> just neat piece of bench gear rather than a home grown cesium standard for
> $100.
>
>
>
> I don't think this part really matters, but it might to some people. Say
> each chip is well below $100, but above $20 each. There might be only one
> part like this on some projects, but for the sake of this poll, let's say
> there are two or three of them. Net is roughly 250 to 500 pins like this to
> solder, on some number of packages. It's part of a project that will cost
> you $250 to $500.
>
>
>
> I'm not talking about opinions on weather it can or can't be done. It
> certainly can be done and is done every day. What I'm asking is - would you
> buy a bag with the parts all in it? If you do are you going to put it
> together in a reasonable amount of time?  Reasonable time might mean
> different things to different people. For the sake of completeness, yes you
> also need to get it working after you assemble it.
>
>
>
> Next layer (you knew there had to be more) - have you done it before
> (anywhere)? / done it in the last 2 years (at home)? / are you set up to do
> it today (at home)?
>
>
>
> I'm not trying to get into "how would you do it / what would you need /
> could you farm it out". Those are also neat questions, but not part of this.
>
>
>
>
> I'll start off the voting (and yes the answers are out of order):
>
>
>
> Done it in the before - yes.
>
>
>
> Done it in the basement / last 2 years - no.
>
>
>
> Set up to do it in the basement - yes, but not set up well.
>
>
>
> Would I buy one - done that before. Likely would again. (counts as a yes).
>
>
>
> Would actually do it in a reasonable amount of time - unlikely.  (That
> counts as a no).
>
>
>
> Any more votes?
>
>
>
>
>
> Bob
>
>
>
>
>
>
>
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-- 
=====
Chris Albertson
Redondo Beach, California