Maker Pro
Maker Pro

Couple of noob questions

Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.

Thanks for any advice!

Dan Lenski
 
P

Puckdropper

Jan 1, 1970
0
[email protected] wrote in @f14g2000cwb.googlegroups.com:

*snip*
* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

Good heat transfer, a clean tip, and lots of practice. I usually go from
one direction to another, either right to left, left to right or middle
outwards. You'll mess a few of these up before you get it down.

*snip*
* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.
*snip*

I don't know about the DC area /per say/, but there's lots of
mail/internet order places around. Radio Shack recently (last 5 years)
has focused mainy on consumer electronics, so mail/internet may wind up
being your best/only option.

Puckropper
--
www.uncreativelabs.net

Old computers are getting to be a lost art. Here at Uncreative Labs, we
still enjoy using the old computers. Sometimes we want to see how far a
particular system can go, other times we use a stock system to remind
ourselves of what we once had.

To email me directly, send a message to puckdropper (at) fastmail.fm
 
D

Dan Lenski

Jan 1, 1970
0
[email protected] wrote in @f14g2000cwb.googlegroups.com:

*snip*


Good heat transfer, a clean tip, and lots of practice. I usually go from
one direction to another, either right to left, left to right or middle
outwards. You'll mess a few of these up before you get it down.

Thanks for the tips!
*snip*

I don't know about the DC area /per say/, but there's lots of
mail/internet order places around. Radio Shack recently (last 5 years)
has focused mainy on consumer electronics, so mail/internet may wind up
being your best/only option.

Thanks, I've ordered a few things from Jameco so far. The trouble is that
I don't have a good "spare parts box" yet... so if I suddenly decide I
need a 74190 IC, I have to wait a few days or pinch 'em from the lab.
Perhaps I ought to buy a couple of those big component assortments from
Jameco...

Dan
 
R

Rich Webb

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?

Without solder. Look for the connectors that use crimp connections, like
these http://www.mpja.com/viewallpict.asp?dept=376&main=83 that crimp
onto a ribbon cable (commonly called IDC for Insulation Displacement
Connector).

Or the kind that crimps individual wires like these from Jameco
http://www.jameco.com/Jameco/catalogs/c254/P108.pdf. You'll need a
proper crimp tool, though. I like my ol' AMP Service Tool (p/n 696202-1)
for this.

I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

Get one of those alligator-clip jobbies commonly called a "third hand"
tool. A small, inexpensive bench vice is handy also; doesn't have to be
terribly large, since most of what you'll probably be working on is
relatively light weight.
* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

The prototype boards with "three holes per" are probably the quickest
and easiest for one-off items. Even perf board without solder pads will
work; just solder to the component leads.

The toner transfer method is probably the easiest for at-home etching
<http://www.pulsar.gs/PCB/a_Pages/4_Products/5b_Transfer_Paper/Transfer_paper.html>
but there are also lots of commercial sources for low quantity prototype
runs that aren't terribly expensive.

See the message <[email protected]> in the thread "Which is
the best hobby do-it-yourself method for making PCB's?" (actually, read
the whole thread).
* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.

Mail order. Digikey. Or Jameco, Mouser, Newark, MPJA, AllElectronics,
....
 
J

James T. White

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

I find the best way is to not solder them at all by using DB connectors
designed to use crimp-on pins. You strip the wire, crimp on the wire
and insert the pins into the DB connector shell in the correct hole.
You will need a crimp tool and extraction tool designed for the pins
you'll be using. You can use simple hand crimpers which cost $20 or a
crimp tool that holds the pin for you, crimps both the wire and
insulation at once, and are controlled so you can't over or under crimp
the pin for $100+. Two of the reasons I prefer the DB crimp connectors
are that there aren't any exposed wires on the back of the connector and
the shells can easily be re-used by simply extracting the pins.

If you must use solder DB connectors, there are a few things you will
need to make this a lot easier. First, you need a good soldering iron
with a small enough tip that you can easily contact just one pin at a
time. If you plan to do much electronics work you should invest in a
temperature controlled solder station with interchangeable tips.
Second, you'll need some type of vise to hold the connector so you can
use one hand to hold the iron and the other to hold the wire. Third,
you will want some small (1/16" or 3/32") heat shrink tubing to insulate
the pins after you solder them. You will want to use 22 to 24 AWG
stranded wire for DB connectors whether you use solder or crimp-on
connectors.

Now for technique. First, strip the insulation from the wire (1/8" or
so), tin the ends and slip a short piece of heat shrink on each wire.
Then fill the solder cups on each pin in the DB connectors you will be
connecting wires to with solder. Then heat the connector pins until the
solder re-melts and slowly insert the pre-tinned wire in being careful
to get all the wire strands in the pin cup. While holding the wire
steady, remove the soldering iron and allow the connection to cool
without moving it. Then slide the heat shrink tubing down the wire,
over the pin and apply heat to shrink it in place.

Good luck with electronics.
 
S

Steve

Jan 1, 1970
0
* What's the best way to solder to a DB-25 parallel port
connector?

The trick to doing this without needing three hands is to
tin both the wire and the solder cup first, then reflow the
solder.

Tin the wires. Unreel six inches or so of solder and bend it
so it sticks up vertically from your bench top. Now you can
hold the iron in one hand and the wire in the other while
you tin the wire.

Hold the connector in a small vise (Panavise or similar.)
Partially fill the solder cups with solder. Hold the wire
against the cup and touch the cup and the wire with the tip
of your soldering iron to reflow the solder. There should
be a tiny bit of solder on the tip to aid in heat transfer.
 
B

Bob Monsen

Jan 1, 1970
0
On Mon, 05 Dec 2005 17:57:30 -0800, dlenski wrote:
<soldering DB25s>

I bought some stuff from these folks:

http://www.winfordeng.com/products/cat_pbc.php

You can also buy those angle connectors directly from digikey, but you
then need to make a PCB to use them.

--
Regards,
Bob Monsen

The concept of fiction was nowhere in Mike's experience; there was
nothing on which it could rest, and Jubal's attempts to explain the
idea were so emotionally upsetting to Mike that Jill was afraid that
he was about to roll up into a ball and withdraw himself.
 
P

Pooh Bear

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

You need to 'tin' the stripped wire before placing it in the solder buckets
of the connector.

I'll bet that makes a *huge* difference.

Graham
 
J

Jasen Betts

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

strip half an inch twist it, put some solder on it, trim it back to about 1/8"
or less and then solder that into the little pocket.
* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

I still use stripboard
* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.

I don't know of any in that area, but I have found the yellow pages to
be helpful. "electronic component suppliers" is the category to look under.

Bye.
Jasen
 
M

Michael A. Terrell

Jan 1, 1970
0
Jasen said:
strip half an inch twist it, put some solder on it, trim it back to about 1/8"
or less and then solder that into the little pocket.

Bye.
Jasen

Your method wastes time and materials. You need to learn how to do a
better job when you solder. Just strip it to 1/8" and tin the wire.
Remember to touch one side of the wire with the hot soldering iron and
apply the solder to the other side. Do not apply the solder directly to
the iron or you will burn away all the flux which will cause bad looking
solder joints.

As far as holding the connector, I like to plug it into a mating
connector mounted on a metal bracket, or clamp it gently in a drill
press vise. Small ones are under $10 in a lot of places. These are good
for holding the bare wires for tinning as long as you don't close the
jaws too tight.
 
B

Bob Masta

Jan 1, 1970
0
On 5 Dec 2005 17:57:30 -0800, [email protected] wrote:

* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

Complete tutorial with hints and tips about the direct felt-tip
method at:
www.daqarta.com/lptxh.htm

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator
 
J

John Popelish

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:

* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end,

That is way too much bare wire. I usually strip about a tenth inch.
And carefully rewrap the strands so that fit the solder cup.
then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess.

Fine solder (.031 or .020 inch diameter, activated rosin core, 60% tin
40% lead, or 63 % tin 37% lead). Narrow, but short tip on a
temperature controlled iron also helps. Too hot, and the wire
insulation melts back and the rosin burns off. Too cold and the
solder doesn't flow well. Here is an example of a low cost one:
http://www.web-tronics.com/lesostc.html
and an even lower cost one:
http://www.web-tronics.com/aueltecosost.html
Is there a
good way to hold things in place for this operation?

You can stick the metal case of the D connector to a magnet from an
old speaker. Or get a small vise:
http://www.hobbylinc.com/htm/dre/dre2214.htm
http://www.hobbylinc.com/htm/pvp/pvp201.htm

Then the trick is to use something like an alligator clip
on a flex joint to hold the wire in the cup, so you have two hands to
operate solder and iron.
http://www.hobbylinc.com/htm/xac/xacx75170.htm

But eventually, you will probably develop the dexterity to hold the
wire between two fingers, and the solder between a thumb and finger on
the same hand.
* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

I'll leave this for the moment. There have been some good threads on
this subject ,lately, that you can look through with Google Group
searches.
* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.

You may discover why we love Digikey and Mouser. They both have
lovely detailed paper catalogs and good web sites with search
capability. Mouser has no minimum order, and Digikey allows you to
choose first class mail postage for small items.
 
J

JeffM

Jan 1, 1970
0
N

noti

Jan 1, 1970
0
Hi all,
I've gotten into electronics thanks to a class I'm taking (only took
until grad school to find out that I enjoy this stuff :)) I've just
built my first microcontroller project and am trying to get myself
outfitted to do electronics work at home. A couple of questions:
* What's the best way to solder to a DB-25 parallel port connector?
I've done it successfully, but made a horrible mess of things. I
started with some stranded 26ga (I think) wire and stripped off about
1/4" from the end, then put it in the little hold on the back of the
pin, got out the soldering iron, and made quite a mess. Is there a
good way to hold things in place for this operation?

You could get a "Helping Hand". The best way to solder stuff is

1) Get a good soldering iron. Preferably a Metcal, but at least something
thats ESD safe, heat controllable and designed for electronics work. Make
sure you have a good, appropriate sized tip.

2) Have the appropriate tools, including: helping hand, vise, flux (good
flux, not crappy RS icky golden crap), solder wick, good soldering iron
(see above), tweezers, pliers, brushes, isopropyl alcohol (and dispenser),
different types of solder, sponge, solder paste, heat shrink, etc. A good
clean workbench with magnifying light as well should go without saying.
These things aren't that expensive, so don't cheap out, get them all and
good quality stuff.

3) If you have stranded wire twist the wires together at the end before
you do anything. Always wet the tip of the soldering iron with solder and
make sure its nice and shiny and clean. If neccessary put some flux on
the wire (probably isn't neccesary in this case). Wet the ends you wish
to join with solder. (You can put them in a vise indepently to hold them
while you wet them). Then simply insert the wire in the pin as best you
can and heat it up with the iron which will reflow the solder as
appropriate. Seal with heatshrink if you feel its neccessary. Good
soldering skills take practice but it also takes decent equipment.
* What's the best way to do home made PCB boards? Clearly breadboards
and wire wrapping will only take me so far :) I've seen the toner
transfer method and a couple of others. What's the easiest one to get
started with? I have access to either laser jet or ink jet printers...

The best way is to stop screwing around with nasty ass chemicals which are
incredibly toxic and will give you crappy results. You think any company
would seriously do this stuff? Even for prototyping? For prototyping if
it has to be done in house its usually done with a milling machine.
Otherwise, you could just design PCBs on some CAD software (Eagle for
instance) and then send them out to a board house. They don't charge that
much. Why would you want to expose yourself to those chemicals if you
don't have to? What do you plan to do with them once you've used them?
Please don't tell me you are going to dump them down the drain.
* Are there any stores in the DC area that sell electronics components?
The local Radio Shack is terrible and I feel guilty taking a diode or
two from work.

You feel guilty about taking a part from work that costs a couple cents,
but not playing with nasty chemicals which you have no good way to dispose
of? Sheesh, I take pens from work which cost more than diodes inadvertantly
all the time. I can't imagine they'll miss it. However, it depends where
in the "DC area" you are. Mark Electronics and Electronics Plus (both in
Beltsville) are reasonably decent. There are plenty of distributors
(Allied, Active, Newark, etc) in this area, although they may not want to
deal with a hobbyist.
 
D

Dan Lenski

Jan 1, 1970
0
The best way is to stop screwing around with nasty ass chemicals which are
incredibly toxic and will give you crappy results. You think any company
would seriously do this stuff? Even for prototyping? For prototyping if
it has to be done in house its usually done with a milling machine.
Otherwise, you could just design PCBs on some CAD software (Eagle for
instance) and then send them out to a board house. They don't charge that
much. Why would you want to expose yourself to those chemicals if you
don't have to? What do you plan to do with them once you've used them?
Please don't tell me you are going to dump them down the drain.

Point taken :) I *do* work in a lab and know something about handling
hazardous chemicals, however I agree that I'd best avoid working with them
at home!!
You feel guilty about taking a part from work that costs a couple cents,
but not playing with nasty chemicals which you have no good way to
dispose of? Sheesh, I take pens from work which cost more than diodes
inadvertantly all the time. I can't imagine they'll miss it. However,
it depends where in the "DC area" you are. Mark Electronics and
Electronics Plus (both in Beltsville) are reasonably decent. There are
plenty of distributors (Allied, Active, Newark, etc) in this area,
although they may not want to deal with a hobbyist.

Wow!!!! I *live* in Beltsville for 1.5 years now. I'd never heard of
either of those places. Will check 'em out ASAP. Thanks for the tips.

Dan
 
D

Dan Lenski

Jan 1, 1970
0
Thanks for all the advice, everyone!

I had been hesitant to try Veroboard because it seems expensive and I know
I'll make lots of mistakes. Today I practiced point-to-point soldering
and was awful at it, so I think I need to use some method that will
require me to not solder little wires to little leads! Today I found this
site with some amazingly cheap Veroboard-type stuff:

http://www.elexp.com/pro_pb16.htm : Veroboard $1.65
http://www.elexp.com/pro_pb19.htm : DIP prototyping board $0.95

Thought I'd pass those links along... about 5x cheaper than anything I'd
seen before!! They also sell kits of capacitors, resistors, ICs, etc.
that seem quite well priced.

Dan Lenski
 
Bob said:
No, stick with it - sooner or later, you're going to pretty
much HAVE to be able to "solder little wires to little leads,"
so you might as well practice it now. You'll catch on. A
couple of tips:

Thanks for the tips, Bob. I think my problem may have been that I was
using a plastic perfboard with no copper cladding. Whenever a drop of
solder touched the perfboard, it would cling to the nearby metal. This
made a mess when trying to solder wires close to the surface of the
board.

Is it correct that solder will NOT adhere to a plastic surface?

I had a much easier time soldering two wires which weren't right next
to the metal surface. I guess the board with copper pads is easier to
work with because the solder will adhere to it.

Dan Lenski
 
B

Bob Myers

Jan 1, 1970
0
Dan Lenski said:
Thanks for all the advice, everyone!

I had been hesitant to try Veroboard because it seems expensive and I know
I'll make lots of mistakes. Today I practiced point-to-point soldering
and was awful at it, so I think I need to use some method that will
require me to not solder little wires to little leads!

No, stick with it - sooner or later, you're going to pretty
much HAVE to be able to "solder little wires to little leads,"
so you might as well practice it now. You'll catch on. A
couple of tips:

1. Don't make the common mistake of pulling the iron away
the moment the solder starts to flow; you WANT to get the
melted solder good and hot, so that it flows properly around
(and into, for stranded wire) the conductors. With the
exception of some semiconductor devices, you don't need
to worry about overheating the components - and for those
that do have this concern, you just need to put a heatsink of
some sort (they're sold in clip-on form, or you can simply place
you needle-nose pliers between the joint to be soldered and
the body of the component, if you're blessed with three hands...:)

2. Make sure the pieces to be soldered are clean - surface
oxidation (or worse yet, some insulating material left on a
wire) with really interfere with the soldering process.

3. Don't use so much solder that you wind up with a huge
glob, but don't skimp, either - a little practice will teach you
the proper amount.

Remember, a good solder joint will be clean and shiny, and
the solder will have flowed well onto the entire surface of the
conductors to be joined - it should be well-adhered to these
surfaces, and not look like it's just barely sitting on top of the
surface ready to be picked off. You should expect to see
some smoke from the joint during the soldering process - that's
also no problem, and is not a sign that you're overheating
anything; it's just flux and other impurities burning off.

Bob M.
 
B

Bob Myers

Jan 1, 1970
0
Is it correct that solder will NOT adhere to a plastic surface?

In general, that's correct - it will, of couse, melt many plastics
while hot, and can really make a mess of things.

Not all metals are solderable, either; copper conductors
obviously are, including wiring which has been "tinned"
(coated with a thin covering of solder or some other
metal/alloy, which both improves the solderability as well
as protecting the bare copper surface from oxidation).
Aluminum, on the other hand, is not easily solderable
with standard tin/lead solders - you can get it hot
enough, of course, but regular solder will just bead
up on an aluminum surface and refuse to "stick."

I had a much easier time soldering two wires which weren't right next
to the metal surface.

Yes, that's pretty typical - beside the solder adhering to
the "wrong" surface, having your wires in contact with
metal for no good reason just makes for that much more
metal you need to heat up - and some smaller irons might
not be up to the task, thus making "cold" solder joints
a lot more likely.

Bob M.
 
Q

quietguy

Jan 1, 1970
0
As a suggestion Dan try and pick up an old electronic device or two or three at
the tip - radios, cassette player, video player etc - their boards have lots
of bits on then that you can practice unsoldering and resoldering, and
soldering wires etc etc, and it will not matter if you ruin them (which you
probably will until you get real good at soldering)

But don't use old monitors or TV sets - these are best left for much later

David
 
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