Homebrew_PCBs

I've seen this done and was wondering if anyone has some words of
wisdom as to how to do it. Basically, I want to attach a ribbon
cable directly to a PCB. The non-PCB end will use an IDC connector
but I can't afford the size of header pins on the PCB. I've seen
several LCDs that have 50 mil spacing hole/pads. The insulation was
stripped of the ribbon cable, the wires inserted in the holes and
soldered. The solder is about 1 mm high. I need 2-3 mm clearance so
that works for me. Clearance on the bottom is a little less a
problem but even SMT connectors are too big.

Are there special tools for this? It sure looks tricky to do. What
size holes/pads?

Phil

You could try simple pads along the edge of the board and solder the
stripped wires directly to the pads. This will give you the
clearance and is easier than drilling all those very tiny holes.

Simply tin each pad and wire seperately than heat them down. Very
easy.

Mark Higgins

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> I've seen this done and was wondering if anyone has some words of
> wisdom as to how to do it. Basically, I want to attach a ribbon
> cable directly to a PCB. The non-PCB end will use an IDC connector
> but I can't afford the size of header pins on the PCB. I've seen
> several LCDs that have 50 mil spacing hole/pads. The insulation
was
> stripped of the ribbon cable, the wires inserted in the holes and
> soldered. The solder is about 1 mm high. I need 2-3 mm clearance
so
> that works for me. Clearance on the bottom is a little less a
> problem but even SMT connectors are too big.
>
> Are there special tools for this? It sure looks tricky to do.
What
> size holes/pads?
>
> Phil

that is an interesting way to do it. certainly could work for a
prototype. Not sure it would do for a small production run though.
thanks.



--- In Homebrew_PCBs@yahoogroups.com, "Mark Higgins" <dirtylude@h...>
wrote:

> You could try simple pads along the edge of the board and solder

the

> stripped wires directly to the pads. This will give you the
> clearance and is easier than drilling all those very tiny holes.
>
> Simply tin each pad and wire seperately than heat them down. Very
> easy.
>
> Mark Higgins
>
> --- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...>

wrote:

> > I've seen this done and was wondering if anyone has some words of
> > wisdom as to how to do it. Basically, I want to attach a ribbon
> > cable directly to a PCB. The non-PCB end will use an IDC

connector

> > but I can't afford the size of header pins on the PCB. I've seen
> > several LCDs that have 50 mil spacing hole/pads. The insulation
> was
> > stripped of the ribbon cable, the wires inserted in the holes and
> > soldered. The solder is about 1 mm high. I need 2-3 mm

clearance

> so
> > that works for me. Clearance on the bottom is a little less a
> > problem but even SMT connectors are too big.
> >
> > Are there special tools for this? It sure looks tricky to do.
> What
> > size holes/pads?
> >
> > Phil

I have soldered the wires directly to "strips" of copper.
(like a edge connector)
Holes would be tiny, or offset, and the wire is not solid and hard to
insert.

The strip pads are possible with a small enough pitch (same as cable)

You should add some mech. restraint, maybe glue.

worked fine for me.

ST

On Fri, 02 Apr 2004 23:01:08 -0000, Phil <phil1960us@...> wrote:

> I've seen this done and was wondering if anyone has some words of
> wisdom as to how to do it. Basically, I want to attach a ribbon
> cable directly to a PCB. The non-PCB end will use an IDC connector
> but I can't afford the size of header pins on the PCB. I've seen
> several LCDs that have 50 mil spacing hole/pads. The insulation was
> stripped of the ribbon cable, the wires inserted in the holes and
> soldered. The solder is about 1 mm high. I need 2-3 mm clearance so
> that works for me. Clearance on the bottom is a little less a
> problem but even SMT connectors are too big.
>
> Are there special tools for this? It sure looks tricky to do. What
> size holes/pads?
>
> Phil
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:

> I've seen this done and was wondering if anyone has some words of
> wisdom as to how to do it. Basically, I want to attach a ribbon
> cable directly to a PCB. The non-PCB end will use an IDC connector
> but I can't afford the size of header pins on the PCB. I've seen
> several LCDs that have 50 mil spacing hole/pads. The insulation

was

> stripped of the ribbon cable, the wires inserted in the holes and
> soldered. The solder is about 1 mm high. I need 2-3 mm clearance

so

> that works for me. Clearance on the bottom is a little less a
> problem but even SMT connectors are too big.
>
> Are there special tools for this? It sure looks tricky to do.

What

> size holes/pads?
>
> Phil

It sounds like you addressed the problem.

Drill holes, offset from one another, diameter to all the wire to
pass.

Insert the wire in the holes and solder. Nip the ends and you have a
solid connection.

You could do two row parallel or staggered as you need.

Dave

sounds reasonable. I'm looking right now at an LCD display that has
the wires inserted through the holes. This makes a good mechanical
connection.

I can proto with what you are suggesting. But I have an eye towards
building a number of them - 50-100 initially - so I need to
understand how it would get done in a manufacturing environment.
mechanical strength is important and maybe epoxy or some such
adhesive would work but I'd really prefer to avoid that step.

By the way, Eagle's DRC really doesn't like putting pads next to
board edges. I'm ignoring it for now but will have to figure that
out.

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

> I have soldered the wires directly to "strips" of copper.
> (like a edge connector)
> Holes would be tiny, or offset, and the wire is not solid and hard

to

> insert.
>
> The strip pads are possible with a small enough pitch (same as

cable)

>
> You should add some mech. restraint, maybe glue.
>
> worked fine for me.
>
> ST
>
> On Fri, 02 Apr 2004 23:01:08 -0000, Phil <phil1960us@y...> wrote:
>
> > I've seen this done and was wondering if anyone has some words of
> > wisdom as to how to do it. Basically, I want to attach a ribbon
> > cable directly to a PCB. The non-PCB end will use an IDC

connector

> > but I can't afford the size of header pins on the PCB. I've seen
> > several LCDs that have 50 mil spacing hole/pads. The insulation

was

> > stripped of the ribbon cable, the wires inserted in the holes and
> > soldered. The solder is about 1 mm high. I need 2-3 mm

clearance so

> > that works for me. Clearance on the bottom is a little less a
> > problem but even SMT connectors are too big.
> >
> > Are there special tools for this? It sure looks tricky to do.

What

> > size holes/pads?
> >
> > Phil
> >
> >
> >
> > Be sure to visit the group home and check for new Bookmarks and

files:

> > http://groups.yahoo.com/group/Homebrew_PCBs
> > Yahoo! Groups Links
> >
> >
> >
> >
> >

Phil
I don't know if you are familiar with SurfBoards (
http://www.capitaladvanced.com ), a SMT to SIP converter board series,
but they have pads on the edge of the board, and a header pin with a
fork in the end that slips over the edge and is soldered to the pad.
If you can find a source for those, then you can just use a regular
female connector on the cable, and the whole thing is only as deep as
your connector is wide.
Richard

interesting idea. I've got one here. It looks like they will only
work for 100 mil pitch but it does have the right height and its
mechanically fairly solid. Worth trying though I'm trying to keep the
production cost reasonably low.

--- In Homebrew_PCBs@yahoogroups.com, Richard Mustakos
<rmustakos@a...> wrote:

> Phil
> I don't know if you are familiar with SurfBoards (
> http://www.capitaladvanced.com ), a SMT to SIP converter board

series,

> but they have pads on the edge of the board, and a header pin with

a

> fork in the end that slips over the edge and is soldered to the

pad.

> If you can find a source for those, then you can just use a

regular

> female connector on the cable, and the whole thing is only as deep

as

> your connector is wide.
> Richard

How about using an edge mounted IDC header such as those found on many hard drives? You'd need about 3.5mm of clearance which is more than you wanted but it's far less labor intensive than stripping, tinning, and soldering a ribbon cable to 100 boards.

Paul Davis

On Fri, 02 Apr 2004 23:01:08 +0000, Phil wrote:
> I've seen this done and was wondering if anyone has some words of
> wisdom as to how to do it. Basically, I want to attach a ribbon
> cable directly to a PCB. The non-PCB end will use an IDC connector
> but I can't afford the size of header pins on the PCB. I've seen
> several LCDs that have 50 mil spacing hole/pads. The insulation
> was stripped of the ribbon cable, the wires inserted in the holes
> and soldered. The solder is about 1 mm high. I need 2-3 mm
> clearance so that works for me. Clearance on the bottom is a
> little less a problem but even SMT connectors are too big.
>
> Are there special tools for this? It sure looks tricky to do.
> What size holes/pads?
>
> Phil
>
>
> Be sure to visit the group home and check for new Bookmarks and
> files: http://groups.yahoo.com/group/Homebrew_PCBs Yahoo! Groups
> Links
>
>
>
>

Phill
I have not looked for them, but I expect they come just like headers,
I'll check my Mill-Max catalog and see if they have any. I checked,
and while they have a million kinds of pins, I don't see any like
that. I'll send an email to the surf board people, and see if they
will tell me where they get the connectors. I suspect who ever sells
them can sell them at 0.05", as well as 0.1" centers.
Richard

> interesting idea. I've got one here. It looks like they will only
> work for 100 mil pitch but it does have the right height and its
> mechanically fairly solid. Worth trying though I'm trying to keep the
> production cost reasonably low.
>

--- In Homebrew_PCBs@yahoogroups.com, Paul Davis <paul_davis@s...>
wrote:

> How about using an edge mounted IDC header such as those found on

many hard drives? You'd need about 3.5mm of clearance which is more
than you wanted but it's far less labor intensive than stripping,
tinning, and soldering a ribbon cable to 100 boards.

>
> Paul Davis
>

If I'm doing it personally, I'd agree but I'm looking to get it built
by some one and want to understand the manufacturing process enough
to make sure it gets done right.

I'll take a look as modular is goodness in my mind.