this is getting crazy

On Sun, 14 Aug 2005 10:54:57 +0000, Joerg wrote:

Hello Michael,

... A Q-tip and IPA removed the ink when
I was done but it made troubleshooting a lot easier.

IPA? I didn't know that India Pale Ale removes Sharpie marks :)
Click to expand...
Enough of 'em will make even the sharpest marks dull.

Me? I just design the marks (and pads, if possible) into the project.
The places I didn't have physical access, I had access in the
FPGA and room for my own logic analyzer.

--
Keith
 
On Sat, 13 Aug 2005 16:59:31 +0000, Jeff L wrote:

"Winfield Hill" <Winfield_member@newsguy.com> wrote in message
news:ddl43b0q9m@drn.newsguy.com...
Jeff wrote...

Spehro Pefhany wrote ...

I'd have been tempted to add one relatively pointless unstuffed
footprint to the 1,999 one to bring it up to an even 2,000. ;-)

I had the same thought - Find a reason for one more part. Maybe
a 0u1 cp or something.

There are rarely too many test points or ground lugs.

True. I have seen boards with a test pint on every node for "bed of nails"
or "flying probe" testing.
Click to expand...
A test "pint". Now that's *my* kind of design!

I put pads/vias in when possible.

--
Keith
 
On Sat, 13 Aug 2005 10:18:58 -0700, John Larkin wrote:

On 13 Aug 2005 08:37:15 -0700, Winfield Hill
Winfield_member@newsguy.com> wrote:

Jeff wrote...

Spehro Pefhany wrote ...

I'd have been tempted to add one relatively pointless unstuffed
footprint to the 1,999 one to bring it up to an even 2,000. ;-)

I had the same thought - Find a reason for one more part. Maybe
a 0u1 cp or something.

There are rarely too many test points or ground lugs.


I like to plop a bunch of grounded thru-holes around my boards. We
insert a few 2-56 screws from below, with nuts on top, as scope ground
clip targets.
Click to expand...
Sounds kinda big. I like to get my grounds within a couple of centimeters
or so. ...sometimes closer.

And right, the test point you really need is seldom there!
Click to expand...
It is if you design it to be there. ;-) Of course that part of the
circuit will never need probing.

*Always* put test points on all chip selects!
Click to expand...
Well...

--
Keith
 
On Sat, 13 Aug 2005 10:24:33 -0700, John Larkin wrote:

On Fri, 12 Aug 2005 22:55:29 -0400, keith <krw@att.bizzzz> wrote:


PS if you guys ever make it down this way, look me up.


Ditto. Lots of planes pass through San Francisco.

No more than any other point.

No more than Hattiesburg, Mississippi?
Click to expand...
Nope. All points have the same number of planes passing through
them.

Oh, did you mean airplanes en-route to somewhere else? Chicago
would seem to have SF beat there too. I don't want to live in Chicago
either. ;-)

--
Keith
 
keith wrote:
On Sun, 14 Aug 2005 10:54:57 +0000, Joerg wrote:

Hello Michael,

... A Q-tip and IPA removed the ink when
I was done but it made troubleshooting a lot easier.

IPA? I didn't know that India Pale Ale removes Sharpie marks :)

Enough of 'em will make even the sharpest marks dull.

Me? I just design the marks (and pads, if possible) into the project.
The places I didn't have physical access, I had access in the
FPGA and room for my own logic analyzer.

--
Keith
Click to expand...

The woman who did the board layouts agreed to add it to new designs,
but these boards were already in production when I was hired.

--
Link to my "Computers for disabled Veterans" project website deleted
after threats were telephoned to my church.

Michael A. Terrell
Central Florida
 
On Sat, 13 Aug 2005 13:05:37 +1200, Terry Given <my_name@ieee.org>
wrote:

Kia Ora Joerg,

Joerg wrote:
Hello Terry,

Size Of board 16.41 x 11.148 sq in
Equivalent 14 pin components 0.58 sq in/14 pin component
Components on board 1335


Man, you guys do large boards. A couple of minutes ago I checked off on
the Gerbers of my last one. Under 200 parts :-(

I saw the costed BOM for that PCB yesterday. total parts cost (excl. 121
LEDs) is $8 less than the micro cost in the (non-functioning) design it
replaced. Its 120 copies of the same thing.

ya gotta love SMT :)


Regards, Joerg

Cheers
Terry
Click to expand...

You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

John
 
Joerg <notthisjoergsch@removethispacbell.net> wrote:
Hello John,

The other issue is that it is so easy to miss a bridge. You wonder why
the board doesn't work like expected, detect a whiff of "ampere smell"
and suddenly find out that one of the chips is as hot as a halogen bulb.

Fluke has a new handheld thermal imager, only $10K, about 1/3 the
price of such gadgets up to now. Tempting.

You might even be able to modify a cheap digital camera for that. I
built a CCD camera from scratch as my master's project in the 80's. I
had to try hard to reduce the IR sensitivity, meaning expensive optics.
Else you could hold it out of the window and see whether someone in
another building in the distance was smoking. You could also "see" a
person in a pitch dark room. It was amazing.
Click to expand...
Err, no.
IR picked up by CCDs (at least silicon ones) is basically out to about 790nm
or so (from memory).
To start emitting radiation in this sort of wavelength, something needs
to get very hot, maybe 800C.
Cigarrettes manage this easily, but nearly all semiconductor packages will
be smoking merrily at this point.
Long integration times can build up faint images, but the cutoff at 790nm
is fairly sharp, and response rapidly plummets to zero.
 
John Larkin wrote:
On Sat, 13 Aug 2005 13:05:37 +1200, Terry Given <my_name@ieee.org
wrote:


Kia Ora Joerg,

Joerg wrote:

Hello Terry,


Size Of board 16.41 x 11.148 sq in
Equivalent 14 pin components 0.58 sq in/14 pin component
Components on board 1335


Man, you guys do large boards. A couple of minutes ago I checked off on
the Gerbers of my last one. Under 200 parts :-(

I saw the costed BOM for that PCB yesterday. total parts cost (excl. 121
LEDs) is $8 less than the micro cost in the (non-functioning) design it
replaced. Its 120 copies of the same thing.

ya gotta love SMT :)


Regards, Joerg

Cheers
Terry



You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

John
Click to expand...
indeed. but the total assembled PCB costs 2/3 of the design it replaced
- the 3 $15 chips I replaced with $1 worth of discretes were a big
saving too :)

For my next trick, I will design out the 3 legacy components, firstly
the 18 $0.56 green LEDs. The customer loves the 17 $0.22 blue LEDs I put
in (which sit behind a blue bit of the label, but used to be red), but I
like the $0.08 red & yellow LEDs.

I especially like the photodiode that Fairchild made just for us,
QSB34CGR. Y'all can buy them now too :)

product testing yesterday, IT LIVES bwahahahahaha

EMC testing tomorrow, should be a doddle (famous last words...)

Cheers
Terry
 
Terry Given wrote...
I especially like the photodiode that Fairchild made just
for us, QSB34CGR. Y'all can buy them now too :)
Click to expand...
That has an IR filter?


--
Thanks,
- Win
 
On Tue, 16 Aug 2005 08:50:33 +1200, Terry Given <my_name@ieee.org>
wrote:

John Larkin wrote:
On Sat, 13 Aug 2005 13:05:37 +1200, Terry Given <my_name@ieee.org
wrote:


Kia Ora Joerg,

Joerg wrote:

Hello Terry,


Size Of board 16.41 x 11.148 sq in
Equivalent 14 pin components 0.58 sq in/14 pin component
Components on board 1335


Man, you guys do large boards. A couple of minutes ago I checked off on
the Gerbers of my last one. Under 200 parts :-(

I saw the costed BOM for that PCB yesterday. total parts cost (excl. 121
LEDs) is $8 less than the micro cost in the (non-functioning) design it
replaced. Its 120 copies of the same thing.

ya gotta love SMT :)


Regards, Joerg

Cheers
Terry



You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

John

indeed. but the total assembled PCB costs 2/3 of the design it replaced
- the 3 $15 chips I replaced with $1 worth of discretes were a big
saving too :)

For my next trick, I will design out the 3 legacy components, firstly
the 18 $0.56 green LEDs. The customer loves the 17 $0.22 blue LEDs I put
in (which sit behind a blue bit of the label, but used to be red), but I
like the $0.08 red & yellow LEDs.

I especially like the photodiode that Fairchild made just for us,
QSB34CGR. Y'all can buy them now too :)
Click to expand...

Hey, how about a photosensitive pcb-mount tamper detector? If light
ever hits the board, the warrantee is void.

product testing yesterday, IT LIVES bwahahahahaha

EMC testing tomorrow, should be a doddle (famous last words...)

Cheers
Terry
Click to expand...
We were just discussing assembly cost with my production folks, and
decided that, on average, it's costing us something like 20 cents per
part, by the time it's all set up, placed, soldered, and inspected.
This is for modest production runs - 10 to maybe 40 boards at a whack
- of fairly dense surfmount with a few thru-hole connectors and such.

John
 
Hello Ian,

Err, no.
IR picked up by CCDs (at least silicon ones) is basically out to about 790nm
or so (from memory).
To start emitting radiation in this sort of wavelength, something needs
to get very hot, maybe 800C.
Cigarrettes manage this easily, but nearly all semiconductor packages will
be smoking merrily at this point.
Long integration times can build up faint images, but the cutoff at 790nm
is fairly sharp, and response rapidly plummets to zero.
Click to expand...
Yes, it's either longer exposure or tricks to squeeze out some extra
dynamic range. I used a Philips NXA sensor in that project. It had some
things added to reduce IR sensitivity because that's basically
undesirable in imagers but it was still quite sensitive. Then I built
three very high speed samplers with diode quads and toroids which
resulted in lots of extra dynamic range. You could see stuff in the dark
that the eye wouldn't be able to resolve.

There were also IR converters you could hook up in the path but these
were very expensive and I don't remember how they worked.

Also, I don't exactly remember if we removed the sensor's glass for the
IR tests or not. I believe we had to.

Regards, Joerg

http://www.analogconsultants.com
 
Hello John,

You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.
Click to expand...
Yes, a four-bitter and maybe even an 8bit uC. But when I asked my
distributor about that he said that TI does not promote the use of their
MSP430 OTPs anymore. That leaves the range below 90c pretty much vacant,
unless you want to go Far East for the uC. Also, there usually isn't an
ADC on chip when under $1, something that one really needs when
replacing lots of mixed signal stuff.

Placing is really cheap. An 0603 resistor comes to about a cent, part,
incoming QC, placement and final QC. Fully burdened. At first I could
not believe it myself. Of course, this is in China and a several
thousand boards a month.

Regards, Joerg

http://www.analogconsultants.com
 
Winfield Hill wrote:
Terry Given wrote...

I especially like the photodiode that Fairchild made just
for us, QSB34CGR. Y'all can buy them now too :)


That has an IR filter?
Click to expand...
No, they left it off for us :)

I'm pleased to say the toy sat up and barked. Were it not for my
deliberate (yeah right) mistake, it would have been first-time. but the
CGR part is fantastic, and pretty too :)

oh yeah, cheap too.

Cheers
Terry
 
John Larkin wrote:
On Tue, 16 Aug 2005 08:50:33 +1200, Terry Given <my_name@ieee.org
wrote:


John Larkin wrote:

On Sat, 13 Aug 2005 13:05:37 +1200, Terry Given <my_name@ieee.org
wrote:



Kia Ora Joerg,

Joerg wrote:


Hello Terry,



Size Of board 16.41 x 11.148 sq in
Equivalent 14 pin components 0.58 sq in/14 pin component
Components on board 1335


Man, you guys do large boards. A couple of minutes ago I checked off on
the Gerbers of my last one. Under 200 parts :-(

I saw the costed BOM for that PCB yesterday. total parts cost (excl. 121
LEDs) is $8 less than the micro cost in the (non-functioning) design it
replaced. Its 120 copies of the same thing.

ya gotta love SMT :)



Regards, Joerg

Cheers
Terry



You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

John

indeed. but the total assembled PCB costs 2/3 of the design it replaced
- the 3 $15 chips I replaced with $1 worth of discretes were a big
saving too :)

For my next trick, I will design out the 3 legacy components, firstly
the 18 $0.56 green LEDs. The customer loves the 17 $0.22 blue LEDs I put
in (which sit behind a blue bit of the label, but used to be red), but I
like the $0.08 red & yellow LEDs.

I especially like the photodiode that Fairchild made just for us,
QSB34CGR. Y'all can buy them now too :)



Hey, how about a photosensitive pcb-mount tamper detector? If light
ever hits the board, the warrantee is void.
Click to expand...
often used in security systems, to detect opening the enclosure.

I toyed with the idea of hiding a photodiode under a bit of label that
doesnt look like it has one, so we could use it to short SCL to 0V to
easily allow a USB flash upgrade (the s/w guy hasnt figured out how to
do that yet, so we use whip out the PCB and use tweezers)

product testing yesterday, IT LIVES bwahahahahaha

EMC testing tomorrow, should be a doddle (famous last words...)

Cheers
Terry


We were just discussing assembly cost with my production folks, and
decided that, on average, it's costing us something like 20 cents per
part, by the time it's all set up, placed, soldered, and inspected.
This is for modest production runs - 10 to maybe 40 boards at a whack
- of fairly dense surfmount with a few thru-hole connectors and such.

John
Click to expand...
that sounds about right. our volumes are a lot higher, so assy cost
plummets. But I am currently gearing up to do some drop tests, to try
and get rid of 8 screws with large washers - the screws cost NZ$0.16
each, $0.30 assembly cost. All up four times as much as the 128-LED
driver circuit.

Years back we were designing a range of motor controllers, which had to
be low cost. We used an existing micro & s/w, and wrapped all new h/w
around it. The original control board had about $45 worth of components,
but all the fiddly screws, spacers etc. for the display & buttons (which
mounted on the control card) cost $27. custom-made stuff, aaargh. Its
amazing how things you dont pay attention to can sneak up and bite you.

Cheers
Terry
 
On Mon, 15 Aug 2005 22:26:57 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello John,

You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

Yes, a four-bitter and maybe even an 8bit uC. But when I asked my
distributor about that he said that TI does not promote the use of their
MSP430 OTPs anymore. That leaves the range below 90c pretty much vacant,
unless you want to go Far East for the uC. Also, there usually isn't an
ADC on chip when under $1, something that one really needs when
replacing lots of mixed signal stuff.

Placing is really cheap. An 0603 resistor comes to about a cent, part,
incoming QC, placement and final QC. Fully burdened. At first I could
not believe it myself. Of course, this is in China and a several
thousand boards a month.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
Actual cost, at one factory, is figured at Y0.1, which is still
comparable to the cost of a cheap part.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Hello Spehro,

Placing is really cheap. An 0603 resistor comes to about a cent, part,
incoming QC, placement and final QC. Fully burdened. At first I could
not believe it myself. Of course, this is in China and a several
thousand boards a month.

Actual cost, at one factory, is figured at Y0.1, which is still
comparable to the cost of a cheap part.
Click to expand...
Over 1c just for placing? That sounds expensive. Not for a logic chip,
of course, but for a resistor.

Regards, Joerg

http://www.analogconsultants.com
 
On Tue, 16 Aug 2005 00:29:51 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Spehro,

Placing is really cheap. An 0603 resistor comes to about a cent, part,
incoming QC, placement and final QC. Fully burdened. At first I could
not believe it myself. Of course, this is in China and a several
thousand boards a month.

Actual cost, at one factory, is figured at Y0.1, which is still
comparable to the cost of a cheap part.

Over 1c just for placing? That sounds expensive. Not for a logic chip,
of course, but for a resistor.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
Yes, the amount I mentioned, 1/10 yen (Y0.1) is 0.09 cent US.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Mon, 15 Aug 2005 03:23:56 +0000, Michael A. Terrell wrote:

keith wrote:

On Sun, 14 Aug 2005 10:54:57 +0000, Joerg wrote:

Hello Michael,

... A Q-tip and IPA removed the ink when
I was done but it made troubleshooting a lot easier.

IPA? I didn't know that India Pale Ale removes Sharpie marks :)

Enough of 'em will make even the sharpest marks dull.

Me? I just design the marks (and pads, if possible) into the project.
The places I didn't have physical access, I had access in the
FPGA and room for my own logic analyzer.

--
Keith


The woman who did the board layouts agreed to add it to new designs,
but these boards were already in production when I was hired.
Click to expand...
A former manager (a non-degreed programmer from the 360 days) had a
favorite word he had tatooed to his blackboard; "xenocryptophobia". He
knew what he was talking about!

--
Keith
 
Joerg wrote:
Hello John,

You can get dumb otp uPs for under a dollar, and it usually costs more
to place cheap parts than the parts cost themselves.

Yes, a four-bitter and maybe even an 8bit uC. But when I asked my
distributor about that he said that TI does not promote the use of their
MSP430 OTPs anymore. That leaves the range below 90c pretty much vacant,
unless you want to go Far East for the uC. Also, there usually isn't an
ADC on chip when under $1, something that one really needs when
replacing lots of mixed signal stuff.
Click to expand...
Joerg,
Considered Atmel's ATTiny13 series?
http://dkc3.digikey.com/PDF/T052/0334.pdf
Only 8 pins, but fast, with a reference and 10-bit A/D, for $0.75 in
100's from DigiKey.

Regards,
James Arthur
 
Terry Given wrote...
Winfield Hill wrote:
Terry Given wrote...

I especially like the photodiode that Fairchild made just
for us, QSB34CGR. Y'all can buy them now too :)

That has an IR filter?

No, they left it off for us :)
Click to expand...
Is that why there's an extra character in the part number?


--
Thanks,
- Win
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top