How to make an STDM cable for cheap
<b>This is from Jayte on pulsar-scope Tue Oct 3, 2000 7:30 am.</b>
Just get the connectors, and a length of cable, and make your own. It's really
not at all difficult. The trickiest part is pressing the two parts of the
connector
together (and it ain't that tricky). A vise would work fine, or, what I use,
one of those wooden clamps--you know, with the two big screws... you
might have seen them in highschool woodshop.
Anyway, I can't get to my Pulsar right now, but if the contacts are standard
0.1" spacing... well, here's the following part numbers from the Digi-Key
catalog:
Part# Price Mfg. part#
MCE20K-ND 4.62 3461-001
MCE20G-ND 1.26 89520-0041
Those are both 3M parts. The first uses gold plated beryllium copper contacts,
the second uses phospher bronze.
CCE20G-ND 3.22 (10 for 24.44)
CCE20T-ND 2.73 (10 for 20.68)
These two are made by CW Industries. The first has gold contacts, the second,
tin.
All four of these are just standard 20 contact card edge connectors with IDC
contacts. (strain reliefs are also available, but probably not necessary for
this
application.) Personally, I think I'd opt for the gold contact material, and
I've
never used the CW Industries products, so...
Then, there's the following ribbon cable:
MC20G-X-ND 3.95 / 5 ft 7.33 / 10 ft 16.36 / 25 ft
(replace the 'X' in the part number with the number of feet desired. eg. 5 , 10
, 25 ....)
It's just plain ol' gray flat ribbon cable, 20 conductors, 28AWG, 7x36 tinned
stranded copper. (the 7 x 36 means there are 7 strands of 36AWG in each
conductor. 'AWG' means American Wire Guage, if anybody's wondering.)
The prices are USD.
They also have color coded cable, if that trips your trigger...
Use a nice sharp pair of scissors, or something like a utility knife and a
steel ruler to cut the cable to length. Press the connectors onto the cable,
and you're in business. The IDC contacts will automatically make the
connections, so... don't try to strip the wires. (in other words, do _not_
strip the wires.) When you position the connector, try to get it at a
half decent right angle to the cable. Begin applying pressure with
whatever tool you're using, and continue until the two parts meet. Just
examine the connector, you'll figure it out...
Often times I'll press the connector on first, then carefully trim the excess
cable off with a _sharp_ blade, using a couple of passes. There are, of
course, tools available for attaching these connectors, but those kinds of
specialty items are, quite often, somewhat on the pricey side.
I've made these, *plenty* of times for hard drives... lot's of stuff, and
they've never failed to work.
Oh, and Daevid, the folks at Digi-Key usually tend not to be complete morons,
but if ya called 'em up trying to use Pulsar speak, or something like
that--yeah,
it's very likely they had no idea what you were talking about. Anyway,
I've
dealt with them repeatedly over quite a few years. They've always struck me
as being very good at what they do (and they package their parts very well,
and all that crap...) Just... thought I'd mention that.
Good luck!
Jeff
<a href=http://www.nb.net/~jetrn/home.html>http ... me.html</a>
<i>Thanks Jeff</i>
Just get the connectors, and a length of cable, and make your own. It's really
not at all difficult. The trickiest part is pressing the two parts of the
connector
together (and it ain't that tricky). A vise would work fine, or, what I use,
one of those wooden clamps--you know, with the two big screws... you
might have seen them in highschool woodshop.
Anyway, I can't get to my Pulsar right now, but if the contacts are standard
0.1" spacing... well, here's the following part numbers from the Digi-Key
catalog:
Part# Price Mfg. part#
MCE20K-ND 4.62 3461-001
MCE20G-ND 1.26 89520-0041
Those are both 3M parts. The first uses gold plated beryllium copper contacts,
the second uses phospher bronze.
CCE20G-ND 3.22 (10 for 24.44)
CCE20T-ND 2.73 (10 for 20.68)
These two are made by CW Industries. The first has gold contacts, the second,
tin.
All four of these are just standard 20 contact card edge connectors with IDC
contacts. (strain reliefs are also available, but probably not necessary for
this
application.) Personally, I think I'd opt for the gold contact material, and
I've
never used the CW Industries products, so...
Then, there's the following ribbon cable:
MC20G-X-ND 3.95 / 5 ft 7.33 / 10 ft 16.36 / 25 ft
(replace the 'X' in the part number with the number of feet desired. eg. 5 , 10
, 25 ....)
It's just plain ol' gray flat ribbon cable, 20 conductors, 28AWG, 7x36 tinned
stranded copper. (the 7 x 36 means there are 7 strands of 36AWG in each
conductor. 'AWG' means American Wire Guage, if anybody's wondering.)
The prices are USD.
They also have color coded cable, if that trips your trigger...
Use a nice sharp pair of scissors, or something like a utility knife and a
steel ruler to cut the cable to length. Press the connectors onto the cable,
and you're in business. The IDC contacts will automatically make the
connections, so... don't try to strip the wires. (in other words, do _not_
strip the wires.) When you position the connector, try to get it at a
half decent right angle to the cable. Begin applying pressure with
whatever tool you're using, and continue until the two parts meet. Just
examine the connector, you'll figure it out...
Often times I'll press the connector on first, then carefully trim the excess
cable off with a _sharp_ blade, using a couple of passes. There are, of
course, tools available for attaching these connectors, but those kinds of
specialty items are, quite often, somewhat on the pricey side.
I've made these, *plenty* of times for hard drives... lot's of stuff, and
they've never failed to work.
Oh, and Daevid, the folks at Digi-Key usually tend not to be complete morons,
but if ya called 'em up trying to use Pulsar speak, or something like
that--yeah,
it's very likely they had no idea what you were talking about. Anyway,
I've
dealt with them repeatedly over quite a few years. They've always struck me
as being very good at what they do (and they package their parts very well,
and all that crap...) Just... thought I'd mention that.
Good luck!
Jeff
<a href=http://www.nb.net/~jetrn/home.html>http ... me.html</a>
<i>Thanks Jeff</i>
-
- Posts: 236
- Joined: Sun Jul 29, 2001 4:00 pm
- Location: Rotterdam, The Netherlands
You're right, it is absolutely possible to construct those kind of cables yourself. But, do you have any experience in how long this cable can be. I don't prefer to place the boards in adjacent slots because of air flow and because of hardware-interrupt-sharing on some slots. So I would like for example, place the boards in slot 1, 3 and 5. Will the length of the cable be a problem??
Cheers,
Rob
Cheers,
Rob
-
- Posts: 2310
- Joined: Sun Mar 25, 2001 4:00 pm
- Location: Canada/France
I bot 2 CW boards by internet, they shipped w/o STDM cable. Emailed dealer, and got an awful runaround. So, . . .
Carried cards into a local electronics repair/hobby shop - the kind of place that sells a million different kinds of electoinics components. The guy took one look at my board, pulled the right connectors out of a little drawer in his giant parts cabinent, reeled a few inches of the right cable, crimped the connectors onto each end with a big press he had behind the counter, and charged me ten bucks. Problem solved, works just fine.
As for cable length, too long will just get messy, so just figure out which slots you're going to use (this IS important usually, everyone's boards and configuration is a bit different, but there's lots of posts here to review on this, then measure the distance between the targeted slots, and add an inch or so for wiggle room. Note that the STDM pins on the top of the CW cards may be a bit forward or back, requiring the cable to run at a angle. Figure length accordingly.
Good luck
Carried cards into a local electronics repair/hobby shop - the kind of place that sells a million different kinds of electoinics components. The guy took one look at my board, pulled the right connectors out of a little drawer in his giant parts cabinent, reeled a few inches of the right cable, crimped the connectors onto each end with a big press he had behind the counter, and charged me ten bucks. Problem solved, works just fine.
As for cable length, too long will just get messy, so just figure out which slots you're going to use (this IS important usually, everyone's boards and configuration is a bit different, but there's lots of posts here to review on this, then measure the distance between the targeted slots, and add an inch or so for wiggle room. Note that the STDM pins on the top of the CW cards may be a bit forward or back, requiring the cable to run at a angle. Figure length accordingly.
Good luck
Is there a reason why you're using .1" pitch connectors and .05" pitch cable? Is that just how it works?subhuman wrote: Anyway, I can't get to my Pulsar right now, but if the contacts are standard
0.1" spacing... well, here's the following part numbers from the Digi-Key
catalog:
Part# Price Mfg. part#
MCE20K-ND 4.62 3461-001
MCE20G-ND 1.26 89520-0041
Those are both 3M parts. The first uses gold plated beryllium copper contacts,
the second uses phospher bronze.
Then, there's the following ribbon cable:
MC20G-X-ND 3.95 / 5 ft 7.33 / 10 ft 16.36 / 25 ft
- next to nothing
- Posts: 2521
- Joined: Mon Jul 29, 2002 4:00 pm
- Location: Bergen, Norway
thant's how it works.soundz wrote:Is there a reason why you're using .1" pitch connectors and .05" pitch cable? Is that just how it works?subhuman wrote: Anyway, I can't get to my Pulsar right now, but if the contacts are standard
0.1" spacing... well, here's the following part numbers from the Digi-Key
catalog:
Part# Price Mfg. part#
MCE20K-ND 4.62 3461-001
MCE20G-ND 1.26 89520-0041
Those are both 3M parts. The first uses gold plated beryllium copper contacts,
the second uses phospher bronze.
Then, there's the following ribbon cable:
MC20G-X-ND 3.95 / 5 ft 7.33 / 10 ft 16.36 / 25 ft
Yes, IDE cable works fine. One word of caution though:
If you ever have to remove the cable from an existing set of connectors (for whatever reason), be careful. You can accidentally pull the contacts out if you're not really careful. These are insulation displacement style connectors which means that each contact is actually like a little scissors (for lack of a better description). When you force the cable down onto the contacts, they actually pierce through the insulation and make contact with the copper wire.
If you ever have to remove the cable from an existing set of connectors (for whatever reason), be careful. You can accidentally pull the contacts out if you're not really careful. These are insulation displacement style connectors which means that each contact is actually like a little scissors (for lack of a better description). When you force the cable down onto the contacts, they actually pierce through the insulation and make contact with the copper wire.
yes, direct soldering, it's what I've done, easy when I get only two boards, a bit harder when I have added the third one
the probem is that now I'm obliged to always move the 3 boards together, hopefully, I don't do that every dayz...
the hint is that you can use the 10 saved bucks to invest in some other electronics parts that make your system really more powerfull...
the probem is that now I'm obliged to always move the 3 boards together, hopefully, I don't do that every dayz...
the hint is that you can use the 10 saved bucks to invest in some other electronics parts that make your system really more powerfull...