> At the moment, I just have a circuit built up on my son's RS learning
> lab, and a spreadsheet of parts and costs.
I updated the web page with the current "functional" circuit and parts
list, but obviously removed the pcb since it doesn't apply any more.
http://www.delorie.com/pcb/smd-
>Ok DJ, you're having FAR too much fun with this. ;)
You've got to have fun at some part. Building 100 kits from the box
of parts I'll get, and mailing them out, isn't going to be as fun as
this part. And it's more fun that fixing the last remaining bugs in
the global puller code.
At the m
DJ Delorie wrote:
Ok, I prototyped this (yay radio shack electronics labs :) with two
0.01u/100k oscillators, each buffered, using up the hex inverter.
The outputs went to D and C of the D flip flop, resulting in the
oscillators changing too fast for the eye to see but the FF changing
about 2-3 t
> Ok, I prototyped this (yay radio shack electronics labs :) with two
> 0.01u/100k oscillators, each buffered, using up the hex inverter.
> The outputs went to D and C of the D flip flop, resulting in the
> oscillators changing too fast for the eye to see but the FF changing
> about 2-3 times a se
> I have some other resistors and caps from the same 1995 thru 2003
> born on dates I'll contribute if wanted. They are sizes like 0805
> and such, not the teeniest -- would be there to provide that
> function part.
I've only scheduled one 0805 (they're big :) and at the moment it's a
general by
For a little more money (~$3.00) take a look at the Nordic Semiconductor reference
design for the NRF24L01 radio transceiver. Lots of small parts and you get a functional
2.4GHz radio when done. I have some commercial modules ($14.95 from Spark Fun)
so the acid test would be easy to setup.
G
I have some other resistors and caps from the same 1995 thru 2003 born on dates
I'll contribute if wanted. They are sizes like 0805 and such, not the teeniest
-- would be there to provide that function part. No LEDs. They can be bought
on ebay "new old stock" too. They'll be with tin/lead p
> To make the challenge to be functional more interesting, I have some
> analog muxes I bought a reel of on ebay I will contribute 100 of if
> DJ will handle the kitting of them along with his boards. They may
> provide extra soldering challenge, since they were made in 2000, are
> on tape, and h
Hi y'all,
To make the challenge to be functional more interesting, I have some analog
muxes I bought a reel of on ebay I will contribute 100 of if DJ will handle the
kitting of them along with his boards. They may provide extra soldering
challenge, since they were made in 2000, are on tape, a
> > By showing phase instead of actual clocking, we avoid the need to
> > have <60Hz frequencies. The LEDs would show the beat between them
> > due to component tolerances, not the actual clocks.
>
>Now THAT is a fun idea!
Ok, I prototyped this (yay radio shack electronics labs :) with two
DJ Delorie wrote:
Hmmm... make two free-running oscillators with the same parts, and
hook two LEDS up between the outputs (one red, one green, in opposite
directions) so the LEDs indicate phase. Or have one clock the D-FF,
and the other provide the D input, use the Q and ~Q outputs to
indicate p
> Panasonic NP061A500A dual PNP with built in bias resistors is in a
> package with a 0.35 mm pin pitch. $0.51 in 100's at Digikey. Is 350
> µm fine enough? ;-)
I have down to 0.40mm pitch so far (the tvsop). The problem becomes
finding cheap FABs at that pitch - 0.40mm is 7.89 mils, so we m
> Does a Schmidt input inverter cost too much?
www.digikey.com ;-)
The tvsop is a hex buffer; if we swap that with a hex inverter it will
be much more useful, and we'd have six gates to play with. The D flip
flop can be set up as a divide by two.
Hmmm... make two free-running oscillators with
On Aug 5, 2006, at 12:56 PM, DJ Delorie wrote:
If we did multiple transistors, they'd have to be different sizes (not
a big deal) and you don't get the fine-pitch challenge with them, like
you do with the mini-gates (SOT-323-5 and TVSOP).
Panasonic NP061A500A dual PNP with built in bias resi
Hi,
On Sat, 2006-08-05 at 14:56 -0400, DJ Delorie wrote:
> > The success of this circuit depends on what `low' valued means here. To
> > get visual frequencies, for a couple of Hertz we might need between 0.1
> > and 1 microfarad or so. We would have to breadboard the circuit to find
> > out app
> Yes - and think about being able instantly identify if the soldering was
> successful or not by seeing the LED blink. 'Built-in diagnostics'...
> That's at least worth another $.02?
Definitely worth $0.02. Not worth $2.00. The trick isn't the
circuit, it's the budget.
__
> The success of this circuit depends on what `low' valued means here. To
> get visual frequencies, for a couple of Hertz we might need between 0.1
> and 1 microfarad or so. We would have to breadboard the circuit to find
> out appropriate values for the cross coupling capacitors. (Although
> p
On Sat, 5 Aug 2006 09:34:20 -0400
DJ Delorie <[EMAIL PROTECTED]> wrote:
> >Even just a little 555-based LED blinker or something would count
> > as "functional" in this case, I think.
>
> 0603 cap = 1 cent
> 0603 led = 7 cents
>
> Even the venerable 555 is too expensive in the small sizes ap
Hi,
Perhaps a bit more low-tech, how about an astable multivibrator? This
circuit needs 2 transistors, 6 (or 7) resistors, and two caps. Add two
LED's and you have a blinker. We used to build these out of leaded
components on a 1.5 x 1.5 inch piece of perfboard. We had students who
wer
>Even just a little 555-based LED blinker or something would count as
> "functional" in this case, I think.
0603 cap = 1 cent
0603 led = 7 cents
Even the venerable 555 is too expensive in the small sizes appropriate
to this project (about $0.60).
Now, if you can think of a circuit that use
Dan McMahill wrote:
I think we should pester Dave to fire up his SEM for some super close up
photos!
You know...My fiance' and I are hunting for a new house...one of the
biggest requirements is enough space for not only my big iron, but for
the SEM. It hasn't even had its vacuum system pum
DJ Delorie wrote:
I think there ought to be a functional test... so how about a simple
surface mount amplifier and input/output jacks.
Again, if you can come up with a working circuit that (1) uses all the
different footprints, (2) costs less than $2, and (3) fits in about
half a square inch, I
DJ Delorie wrote:
> Again, if you can come up with a working circuit that (1) uses all the
> different footprints, (2) costs less than $2, and (3) fits in about
> half a square inch, I'm all for it.
My former employer did a little pcb as a christmas gift for well known
customers. It is dual use:
Steve Meier wrote:
I think there ought to be a functional test... so how about a simple
surface mount amplifier and input/output jacks.
Steve Meier
I think we should pester Dave to fire up his SEM for some super close up
photos!
Actually just some decent optics with a camera mount would be
> I think there ought to be a functional test... so how about a simple
> surface mount amplifier and input/output jacks.
Again, if you can come up with a working circuit that (1) uses all the
different footprints, (2) costs less than $2, and (3) fits in about
half a square inch, I'm all for it.
I think there ought to be a functional test... so how about a simple
surface mount amplifier and input/output jacks.
Steve Meier
DJ Delorie wrote:
>>Is the intent to practice iron soldering, or test oven bake cycles
>>with solder paste?
>>
>
>Almost missed this comment.
>
>The intent is to s
> Is the intent to practice iron soldering, or test oven bake cycles
> with solder paste?
Almost missed this comment.
The intent is to see how small a part you can hand solder. There was
a thread about that a while back.
I, for one, want to try my hand at this so I know how small a part I
can
> My first thought is it could be a helpful test aid if it had
> graduated versions between close to chip legs/lands sizes and
> oversize that let lots of solder cling on. By oversize, I mean only
> in the direction of chip leg lengths, not fatter.
Well, the chips are the expensive parts. Other
Is the intent to practice iron
soldering,
or test oven bake cycles with solder paste?
DJ Delorie wrote:
The questions are: What footprints to use for a proper "challenge"?
We've got four each for the 0201 through 0805 parts, and I can make
the two ICs have either long or short pads. Plus, what
> You forget that DJ has to pay a premium to have the parts delivered
> up his driveway.
Actually, they *don't* get delivered up the driveway. I have to go
get them - they'll easily fit in my oversized mailbox.
In the winter, UPS and Fedex won't deliver up the driveway either.
They leave it at
> Here's a nickle .
Cool, that $5 more I can spend on PCB fab if needed. Actually, the
budget was for double sided, since it fits on single sided, that's
another $7. At the moment, I've got $16 slack, not counting paper and
tape and such. Unless we want different footprints on the other si
John,
You forget that DJ has to pay a premium to have the parts delivered up his driveway.
George
On Fri, 2006-08-04 at 20:12 -0400, John Luciani wrote:
On 8/4/06, DJ Delorie <[EMAIL PROTECTED]> wrote:
> Besides, at that price, all you get is some pF caps and a couple of
> inverter/buffer
On 8/4/06, DJ Delorie <[EMAIL PROTECTED]> wrote:
Besides, at that price, all you get is some pF caps and a couple of
inverter/buffer gates. The most expensive part on there is the US-8
footprint, which is a single D flip flop, at 31 cents.
Here's a nickle .
The On-Semi D flip-flop, NL17S
> What if the board actually did something if successfully soldered
> together?
Then you'd worry about destroying the components ;-)
By having it not do anything, I'm free to choose the least expensive
item in each footprint, and the user can solder and desolder as many
times as they like, and n
On 8/4/06, DJ Delorie <[EMAIL PROTECTED]> wrote:
Plus, what about soldermask? What's ideal? Or should we make it more challenging (andperhaps cheaper) by not having one at all?I vote for having a solder mask.
I'm also figuring score-and-snap to separate the boards. I can leavea bigger border
I've been poking at this idea on and off, I think I have a viable plan
in place, except that Olimex is on vacation this month, and they're
the best bet for getting the boards cheap enough, assuming they can do
0.40mm pitch (7.87 mil) with their 8 mil rules. If I have to go with
a more expensive f
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