Easier Header Connectors

teaserHeader connectors are ubiquitous on dev boards for making connections between boards and for connecting all types of external devices.  The TAP-28 board uses 3-pin and 6-pin single-row header connectors for everything.

As prevalent as these connectors are, making connections isn't a trivial matter.  Crimp connectors are common, but assembling them isn't simple. A previous article provided some tips on putting these connectors together but it's still been a time-consuming, not-wholly-successful task.  After looking at the options, I've found a better method.

Amp's MTA connectors are IDC single row connectors for individual wires.  The connectors go together easily and are very inexpensive compared to crimp-type connectors.  The photo below shows a few examples of these connectors.  They are available with a range of contacts from a number of vendors.

photo_1


In this photo, you can see the metal IDC contacts and the barbs on the housing to hold the wires in place before they are inserted.  The contact cuts through the cable jacket so it's not necessary to strip the cable before assembly.  The blue arrows pointing to the white connector show an optional feature - alignment tabs.  If a keyed header is used, these tabs ensure that the connector is properly aligned (i.e., not put together one pin off).


photo_2

The two photos below show a connector mated to a keyed header.

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A special punchdown tool is required to assemble these connectors.  It's about US$25, which seems slightly expensive, but if you compare the cost of connectors and value your time, the value quickly becomes apparent.

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 Using these connectors couldn't be any easier (at least not without a much more expensive auto-insert tool).  Line the wire up, and poke it down using the tool.  I've built a little jig to hold the connector in place which reduces the need to have 3 hands.  The next photo shows the wire in place.

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And it's a simple matter to insert it using the tool.

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The five wires I need are finsihed in seconds.

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The connectors are available in two configurations.  The photo above shows a closed connector - the wires can only exit from one side.  They are also available in an open type - the wires can extend in both directions.  In the photo below, the white connector is the open type, the red is a closed type.

c_vs_o

Using open type connectors permits making daisy-chain cables with connectors along the length.  The cable I'm building here is for use with the TAP-20-USB board - an intermediate connector will be used to connect to the PICkit 2.  Each wire continues through the second connector.  The photo below shows the wires aligned and ready to be inserted.

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And the wires are simply poked home.

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Here's the final cable assembly.  The far end of the cable will be spliced to a USB-A cable.

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As handy as these connectors are, there is one major limitation.  The right gauge of wire must be used with each connector.  There is no tolerance in this regard.  The connectors are color-coded to indicate the wire size.

Color Wire Gauge
Red 22
White 24
Blue 26
Green 28

 

In case you're wondering why my connectors aren't assembled directly on the end of the USB cable, the power conductors in most USB cables are a larger gauge than the signal conductors.  One size of connector cannot accommodate the different gages.

Jameco Electronics has the best prices on these connectors that I have seem.  $0.09 each at quantity 1.  The punchdown tool is US$30 however.  It's considerably cheaper at Digikey.  Jameco Catalog Page.  You may find better prices elsewhere.


Posted: 6 years 4 months ago by MrDEB #8552
MrDEB's Avatar
nice solution but $25 for the tool.
I keep looking for similar but uses a ribbon cable
http://www.mouser.com/ProductDetail/Mol ... j7xavCU%3d
but want only 5 circuits unless you short the two rows together and use only one row?
have done that since the Junebug has a 10 pin header. made an adapter for.
Posted: 6 years 4 months ago by Jon Chandler #8553
Jon Chandler's Avatar
If you want to use one side of a dual row connector, there's no need to short the sides together - just be sure to use the same side of the connector on each end.

Comparing costs for a 6 pin connector from Jameco. The 6-pin IDC type is $0.09 each. The alternative crimp type is $0.45 for the keyed type, plus $0.05 per contact, making the total $0.95. Any kind of crimper that will work for these connectors is at least $10.

Just considering the connector costs for a 6-pin ICSP connector would be $0.18 for the IDC connectors or $1.90 for the crimp-type connector. Even if you don't value your time, the $25 tool is paid off pretty quickly.
Posted: 6 years 4 months ago by MrDEB #8557
MrDEB's Avatar
How can the $25 tool be of value for the hobbyist? YES the professional user would benefit from the use of the tool.
Being a hobbyist I found, and was suggested by ?? to use adapter plugs as pictured.
I like the ribbon cable for two reasons.
1 I like the neat compactness and ease of using an IDC plug similar to the one I posted and is pictured.
2 I have LOTS of free ribbon cable
When selecting parts etc the $$$ is one of the main concerns.
The Junebug uses a 10 pin header thus I needed an adapter.
I like those plugs you posted Jon but way outta my price range at $25 just for the tool to use them.
Thanks for the suggestion on them their plugs
Posted: 6 years 4 months ago by Jon Chandler #8559
Jon Chandler's Avatar
MrDEB, you're missing the point here.

The IDC connectors you've mentioned are for dual-row headers. I have seen the same thing for single row headers in the past, but as far as I can determine, they are no longer available.

My need, and the point of this article, is to make connections to single-row, 0.1" pitch headers that are found on almost every dev board. The 0.1" headers are a de-facto standard. Given the headers are everywhere, I need a way to make connections. This isn't a one-time need but a need every time a connection gets made to a board.

The alternatives that I know about are:
    1. Purchase pre-built cables

    2. Use crimp-type connectors

    3. Use the subject IDC connectors

Given this reality, the option here is the most cost-effective as I have outlined. Given that you're not often making connections to the real world, it may not be the best option for you. For me, the savings in time, frustration and even cost over option 2 are immense.
Posted: 6 years 4 months ago by W4GNS #8560
W4GNS's Avatar
I'm 100% certain you did not mean to do so, but you answered your own question. Each point you raise is specific to YOU (MrDeb) not the general hobbyist public. Not everyone has free ribbon cable or a MayBug and on down your list.
Jon made to post for everyone interested. Not just one person.
How can the $25 tool be of value for the hobbyist? YES the professional user would benefit from the use of the tool.
Being a hobbyist I found, and was suggested by ?? to use adapter plugs as pictured.
I like the ribbon cable for two reasons.
1 I like the neat compactness and ease of using an IDC plug similar to the one I posted and is pictured.
2 I have LOTS of free ribbon cable
When selecting parts etc the $$$ is one of the main concerns.
The Junebug uses a 10 pin header thus I needed an adapter.
I like those plugs you posted Jon but way outta my price range at $25 just for the tool to use them.
Thanks for the suggestion on them their plugs
Posted: 6 years 4 months ago by MrDEB #8561
MrDEB's Avatar
I realize that Jon is giving suggestions and my adapter board is an alternative method.
I wish they made single row IDC ribbon cable connectors.
The adapter in my picture uses a 8 pin IDC/PCboard/8 pin single row socket connector.It's a viable alternative for a single row connector.
Yes Jons information is helpful but in my situation too expensive. Just wish them single row IDC connectors were still available.
Posted: 6 years 4 months ago by Jon Chandler #8566
Jon Chandler's Avatar
Here's a picture of my completed cable. It's for programming the 18F14K50 with shared ICSP and USB pins.

Posted: 6 years 4 months ago by Jon Chandler #8572
Jon Chandler's Avatar
These IDC header connectors may not solve any need that MrDEB has, but they are working well for me.

If you've read any of my articles here or looked at the TAP-28 board, you know I like to use 6-pin keyed headers for most of my connections, including between the PICkit 2 and ICSP connector. I've collected a number of short back-to-back cables over the years but they always seem to be in short supply. Pre-built cables like this aren't always easy to come by. Here's Sparkfun's version, which you'll notice is out of stock.




I just saw a piece of ribbon cable on my desk that had some useless connectors on it, and two of the white IDC connectors. Aha, I can build one of these in just a couple minutes. Here's my version.



I used 18 cents worth of connectors and I got the length of cable I wanted.

Like I said, if these connectors solve any problem you have, the tool cost will be quickly amortized.
Posted: 6 years 4 months ago by Jon G #8574
 Jon G's Avatar
Not to mention, ribbon cable is EVERYWHERE, tons of it. I might have to get some of these... It does get tiresome having to fashion things together and what about when you want a "finished product?" You'll need something like this or you'll need to purchase a cable... Those are the options.

The tool itself doesn't look too sophisticated. If someone wanted to be really "cheap" they could probably make one using a Dremel and a screwdriver. Though if they planned on doing much more than just a few, the tool would be the best bet since you'll get the proper insertion depth every time. (that sounds dirty)
Posted: 6 years 4 months ago by MrDEB #8576
MrDEB's Avatar
I was ondering if ribbon cable could be used on the connectors Jon posted info on.
Looking at the picture I guess ribbon cable is back on the table.

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