Homebrew_PCBs

Anyone up for making a simple PCB (layout & board) from a simple
schematic over at http://sanisis.netfirms.com/. Also you can e:mail
me about the prices, et cetra.

k2k

Looks like a wireless to IR relay. Questions:
Is pin 8 of the PIC supposed to be connected to Vdd?
What's with the feedback resistor on the shift register?

mickeym

kaytea2k wrote:

>Anyone up for making a simple PCB (layout & board) from a simple
>schematic over at http://sanisis.netfirms.com/. Also you can e:mail
>me about the prices, et cetra.
>
>k2k
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...>
wrote:

> Anyone up for making a simple PCB (layout & board) from a simple
> schematic over at http://sanisis.netfirms.com/. Also you can e:mail
> me about the prices, et cetra.
>
> k2k

Why not just put it together on a breadboard ?

$25 bux and you can make circuits in a few hours.

http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?
prmenbr=91&prrfnbr=347181&cgrfnbr=501&ctgys=

Nice thing is that you can fix things very quickly.

One thing you'll learn one way or another is that quite often the
schematics posted, in magazines or on the web, are not complete.

The more complex, the better chance there is a flaw.

Nope Pin 14 is for power. But the feedbak resistors are there
because the receiver gives some interference.

--- In Homebrew_PCBs@yahoogroups.com, mickeym <whitemouse@m...> wrote:
>
> Looks like a wireless to IR relay. Questions:
> Is pin 8 of the PIC supposed to be connected to Vdd?
> What's with the feedback resistor on the shift register?
>
> mickeym
>
> kaytea2k wrote:
>
> >Anyone up for making a simple PCB (layout & board) from a simple
> >schematic over at http://sanisis.netfirms.com/. Also you can
e:mail
> >me about the prices, et cetra.
> >
> >k2k
> >
> >
> >

--- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha" <dave_mucha@y...>
wrote:

> --- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...>
> wrote:
> > Anyone up for making a simple PCB (layout & board) from a simple

it is pretty simple design-wise. An input, a timer, a memory, and a
processor. Albeit I haven't tested it, but that is why I brought it
to forum.

> > schematic over at http://sanisis.netfirms.com/. Also you can

e:mail

> > me about the prices, et cetra.
> >
> > k2k
>
>
> Why not just put it together on a breadboard ?
>
> $25 bux and you can make circuits in a few hours.
>
> http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?
> prmenbr=91&prrfnbr=347181&cgrfnbr=501&ctgys=
>
> Nice thing is that you can fix things very quickly.
>
> One thing you'll learn one way or another is that quite often the
> schematics posted, in magazines or on the web, are not complete.
>
> The more complex, the better chance there is a flaw.

--- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...> wrote:

> --- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha" <dave_mucha@y...>
> wrote:
> > --- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...>
> > wrote:
> > > Anyone up for making a simple PCB (layout & board) from a simple

> it is pretty simple design-wise. An input, a timer, a memory, and a
> processor. Albeit I haven't tested it, but that is why I brought it
> to forum.

You dropped your reply smack in the middle of the quoted text. Makes
it rather difficult to read. ;'/

If this needs to be tested still, why not head over to the
Electronics_101 list and ask for help there?

http://groups.yahoo.com/group/electronics_101

There's not much point in having someone make a PCB for you if it
isn't tested yet. It does not look like a complete schematic on quick
inspection.

Steve, the moderator

--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@y...>
wrote:

> --- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...>

wrote:

> > --- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha"

<dave_mucha@y...>

> > wrote:
> > > --- In Homebrew_PCBs@yahoogroups.com, "kaytea2k"

<kaytea2k@y...>

> > > wrote:
> > > > Anyone up for making a simple PCB (layout & board) from a

simple

>
> > it is pretty simple design-wise. An input, a timer, a memory,

and a

> > processor. Albeit I haven't tested it, but that is why I brought

it

> > to forum.
>
> You dropped your reply smack in the middle of the quoted text. Makes
> it rather difficult to read. ;'/
>
> If this needs to be tested still, why not head over to the
> Electronics_101 list and ask for help there?
>
> http://groups.yahoo.com/group/electronics_101
>
> There's not much point in having someone make a PCB for you if it
> isn't tested yet. It does not look like a complete schematic on

quick

> inspection.
>
> Steve, the moderator

This is what I was saying in my post. Many on-line schematics are
only partial.


The best way to do something is to breadboard it to see if and how
the circuit works and what is needed.

To post a link and then hope someone will read the schematic, layout
a board, troubleshoot it and then make you a board is asking for a
great deal of work as well as a lot of responsibility.

To lay out a board from a schematic and select/verify parts you can
be looking at a couple hours.

to lay out a board from that an eleminate any potential problems with
stray voltages and spurious signals may take another couple hours.

So, to read a schematic and layout a board could easily be a couple
hundred dollars. And there is no gurantee that the schematic will
actually work.

To review the engineering behind the circuit can be simple like the
power supply of the very first posted schematic, or it can be more
than a few hours. In monitary terms, another couple hundred bux.

If you have a tested board and have the schematic, most of us can do
a rather fast copy and paste into schematic program and make a board.

The tried and true method is to breadboard the circuit. That way,
you know the chips, and that the circuit works.

THEN make a board.

A much cheaper way is to buy perf board at radioshack and mount your
stuff on that.


Dave

> The tried and true method is to breadboard the circuit. That way,
> you know the chips, and that the circuit works.
>
> THEN make a board.
>
> A much cheaper way is to buy perf board at radioshack and mount your
> stuff on that.
>
>
> Dave

Basically i agree on what you say, the above which i snipped off.
But i do not agree that every any any board has to be breadboarded first.

If you have a schematic which you understand, where there are no doubts and
guess work there is a good chance the first pcb will be useable.

You can make many mistakes on a breadboard, and maybe destroy more
components
than see any results. this depends a lot on your personal working methods.

I often make breadboards (the white spring-loaded type), but only if i am
unsure
of the circuit and want to experiment.

It also depends a lot on how long it takes you to make a board (and how
much it costs).
If it takes actually less time to get a finished board than wire up a
breadboard why not
just make one? With good schematics and layou software (no corel draw
steve ;-) ) the
possibility of making fatal errors (for the parts) is much less.

I have confused the important wires and pins often enough to know what
happens
if you reverse the power connections.....

To the perfboard: well, this is Homebrew_PCBs, and i trust the people here
know the difference between perfboard and a custom pcb...


ST

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@g...> wrote:

>
> > The tried and true method is to breadboard the circuit. That way,
> > you know the chips, and that the circuit works.
> >
> > THEN make a board.
> >
> > A much cheaper way is to buy perf board at radioshack and mount

your

> > stuff on that.
> >
> >
> > Dave
>
> Basically i agree on what you say, the above which i snipped off.
> But i do not agree that every any any board has to be breadboarded

first.

>
> If you have a schematic which you understand, where there are no

doubts and

> guess work there is a good chance the first pcb will be useable.

I agree, especially if you have confidence you KNOW the circuit
works.

On my boards, I will often add extra pairs of pads on all power
connectors. I just make a project that was intened for use with a
wall wart, but didn't find out all they had was 24VDC. with 3 pins
and pads, it was easy to add a dual stage voltage regulating circuit
and drop the power in stages to allow for the heat sinks.

Ditto for the switch connection. jumpers and pads for resistors so
there are about 5 ways to use the switch. pull-up, pull-down, 2
different pins on the micro and even jumper to another pin on the
micro.

also, I always inlude a set of pins from the micro out to a header in
the event I may want to add a serial connection to something....

BUT, what we have on the list is one person asking to have someone
else make a board, and that the group check the schematic. : )

If the circuit was simple, and/or tested, I'd be happy to make the
boards. But since the schematic is clearly part of another larger
system, there is no way to know the boards will work...

...OK, I KNOW *MY* boards will connect per the schematic, but I don't
know the CIRCIUT will work as expected.

but, as they say, people who never make mistakes, never get to see
the exciting kinds of electrical displays and fireworks that I do !

Dave

> If the circuit was simple, and/or tested, I'd be happy to make the
> boards. But since the schematic is clearly part of another larger
> system, there is no way to know the boards will work...

If the board is made correct, and the schematic is wrong, the guy making
the board can not be held responsible (or so it is written in the bible
;-) )

> ...OK, I KNOW *MY* boards will connect per the schematic, but I don't
> know the CIRCIUT will work as expected.

That's too true...

>
> but, as they say, people who never make mistakes, never get to see
> the exciting kinds of electrical displays and fireworks that I do !
>

yes, all the funny smoke and tabletop fireworks... amazing...

I hope you don't laugh if i tell you i blew up my soldering station today.
The temperature display was off 30 degree and i NEEDED to adjust it.
i dropped the board on the metal chassis, power on (as always) and sparks
were
flying. Well, i can easily fix it, need to exchange a socketed IC only but
still
damn stupid thing to do....

yea well, i think i will go back to my soldering again.
(Good thing you can use the ersa ptc irons without the station on a
variable supply.
the temperature stays within 10 C and that must do until i get the new IC.)

ST

I don't know what the problem is but I know that the design is
sound. I have experience with design from the number of
electrical/electronic engineering courses I took in college. Though
EE is not my major I understand the components and how they work.
The schematic posted @ sanisis.netfirms.com is a schematic I redid
inorder to make it easier for a fabricator.

I have gone over the schematic here with some professional
fabricators and I am HERE trying to get you all to help. Any poster
should know that a schematic should be tested and working. I believe
once I have a layout and prototyped board then there should be no
problem as far as adding and removing.

If you have any constructive suggestions or are able to DO the work
then please reply to my e:mail. kaytea2k@....

Karega

--- In Homebrew_PCBs@yahoogroups.com, "kaytea2k" <kaytea2k@y...>
wrote:

> I don't know what the problem is but I know that the design is
> sound. I have experience with design from the number of
> electrical/electronic engineering courses I took in college.

Though

> EE is not my major I understand the components and how they work.
> The schematic posted @ sanisis.netfirms.com is a schematic I redid
> inorder to make it easier for a fabricator.
>
> I have gone over the schematic here with some professional
> fabricators and I am HERE trying to get you all to help. Any

poster

> should know that a schematic should be tested and working. I

believe

> once I have a layout and prototyped board then there should be no
> problem as far as adding and removing.
>
> If you have any constructive suggestions or are able to DO the work
> then please reply to my e:mail. kaytea2k@y...
>
> Karega

Please don't take our conversation as criticism. If you review the
posts, we chat about things all the time and stray from the topic
with a little energy to keeping it generally about electronics and
making boards.

The schematic is a very general outline.
http://sanisis.netfirms.com/

The are no notations on the caps on the power supply. probably
0.01uf or 0.1uf,

all resistors could be 1/4 watt

no spec for the diode

RX433 is not a standard part, but a part in kit form. there are a
few variations on that part.

No antenna connection device is listed.

The 555 capacitor is not listed for pin spacing, it could be 100 mil
or 400 mil as different caps have hugely different pin spacing.

The transistors for the LEDs are not called out, they are probably
TO92 case, but are the EBC, BCE, ??

Power connections are not called out, are they solder pads for wires
or spacing for screw terminals or pins for a Molex or other ?
if screw terminals, are they 100mil ? 3.5mm ? 5 mm ? 5.09mm ? 3/8
inch?

A lot of people tie MCLR to Vcc with a 4.7k or 10k and not 100k to
ground.

There is no ISCP listed, so the PIC would need to be pulled for
programming.

I'm not saying that we can't do such a board, but that with roughly
140 holes there would be 20 mil for resistors and caps, 29 for the
DIPs, something for the connectors, and something for the antenna.

The only way most of us would consider making such a board is if we
had all the parts to measure or if all the parts were fully listed on
the schematic.

For example, I just made a board for a customer and the manufacture
of the switches gave me physical dimmentions for the pins and
electrical connections. Only problem is that the information was
wrong. on a switch pins 1 and 3 were common when pins 1 and 2 were
listed as common. instant short. required modification of the
board. Luckily, the customer gave me the data from the
manufacturer. Customers are sooo much more understanding when they
make the mistakes.

It may be a simple matter to download ExpressPCB and use that free
layout software, or WinQCad as that is free and has a very shallow
learning curve.


Please understand that making a board requires multiple layers.

The most general is done, your schematic.

next is parts selection followed by the math for verification that
the ranges are compatible.

Next is re-selection of parts as needed followed by manufacture or
supplier part numbers.

that is followed by package physical dimensions, hole sizes, pin
spacing clearance around parts for heat, ventilation, connection,
clearance etc.

then the board can be laid out with hopes that there are no
mistakes. A TO-92 BEC may be purchased when a EBC was laid out.
requires some attention when stuffing the board. ie: my switch
problem.

Then of course, there is the final step of making sure it will fit an
enclosure or housing, and that it has holes for mounting.

I didn't take the time to write this to make fun, but to try to
convey that it looks really really simple, but this is one area of
endeavors where the devil is in the details.

Electrical spec details
connection details
physical layout details
and physical properties details.

All those have to be 100% compatible or the thing won't work.

I listed enough questions that would prevent me from making such a
board from this schematic and I bypassed some of the more obvious
ones in case others want to point out some of the missed requirements.

But, I can say with total certainty, that the board as laid out with
the parts listed in the schematic will not work. There is at least
one flaw that will prevent proper operation.

Dave

Excellent, Dave!


[Non-text portions of this message have been removed]

The free Eagle program has all of the symbols. I had some time so I
started the schematic.

But, I asked about pin 8 because the schematic shows it as a control
signal AND connected to Vdd.

I wonder also about the PNP transistors, should probably be NPN. Is Vdd
really a battery?

Not a showstopper, but do you really need all three shift registers?
Plus, I would throw in a pair of small caps onto the crystal.

And those feedback resistors still bug me (the RX433 bothers the shift
register?). Power decoupling is needed, too.

I presume all DIP packages and big LED's? I don't mind helping, just
have to have details.

mickeym


kaytea2k wrote:

>Nope Pin 14 is for power. But the feedbak resistors are there
>because the receiver gives some interference.
>
>--- In Homebrew_PCBs@yahoogroups.com, mickeym <whitemouse@m...> wrote:
>
>
>>Looks like a wireless to IR relay. Questions:
>>Is pin 8 of the PIC supposed to be connected to Vdd?
>>What's with the feedback resistor on the shift register?
>>
>>mickeym
>>
>>

> Please don't take our conversation as criticism. If you review the
> posts, we chat about things all the time and stray from the topic
> with a little energy to keeping it generally about electronics and
> making boards.
>
> The schematic is a very general outline.
> http://sanisis.netfirms.com/
>
>

Thanks for the reply. Some knowledge of things that should be always
considered is helpful.

Karega