EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: djacobow on January 23, 2014, 10:19:01 pm
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tl;dr: What is the easiest way to make simple cables for connecting between headers?
Longer:
I've started making PCBs and, of course, the standard 0.1" header is simple and beautiful for getting signals on and off a board.
But I'm getting driven crazy trying to make pluggable connections for them. Whether I put sockets on the board and make pin cables or put pins on them and make socket cables, it's a PITA. I know I could buy appropriate-sized ribbon cables with connectors on them, but since the number of pins I need is never the same, nor do I need the same lengths, etc, it seems stocking a variety is expensive and hassle-filled. And you never have in your box exactly what you need, so it's back to DigiKey to pay shipping again.
What I do now is break up chunks of pin headers and solder #24 wires to them, then heat-shrink the whole mess. It's super-tedious, especially considering my rapidly diminishing near vision.
What do hobbyists who want cheap, easy,and quality results do?
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I bought an Engineer PA-20 crimping tool from eBay (an Ireland or UK importing them from Japan, he shipped it me from UK). Good tool, does headers, molex, pci express conectors, etc no problems with it.
Here's the actual eBay page for it, I still have the order email in my mail client: http://www.ebay.co.uk/itm/universal-mini-crimping-tool-molex-jst-amp-crimp-terminal-pliers-engineer-pa-20-/261110204270?ssPageName=ADME:L:OC:US:3160 (http://www.ebay.co.uk/itm/universal-mini-crimping-tool-molex-jst-amp-crimp-terminal-pliers-engineer-pa-20-/261110204270?ssPageName=ADME:L:OC:US:3160)
I buy my stuff usually from Farnell because the shipping is cheap.
As usual (murphy's law) when I want to give you links the Farnell site is down (some dns error).. anyways, copying the product numbers from invoices, you can paste the numbers in search box on farnell's site and they should point you to actual products.
I bought the metal connectors from Farnell, in bags of 100: http://uk.farnell.com/harwin/m20-1180046/contact-socket-30-22awg-crimp-pk100/dp/1022220 (http://uk.farnell.com/harwin/m20-1180046/contact-socket-30-22awg-crimp-pk100/dp/1022220)
Kind of expensive (around 10$ after vat and all that) because it's Harwin but I was too lazy to search for their "Multicomp" (farnell's brand, buying bulk from others) versions of the connectors, or te connectivity brand or some other.
The plastic headers are super cheap, there's a whole series on Farnell under their Multicomp brand ... some examples of what I stocked below
code , min quantity, price each, series, description (at least that's what it in July 2013 when this invoice was made)
1593506 10 .0540 2226A-02 CRIMP HOUSING, 1 ROW, 2 WAY
1593509 10 .0720 2226A-05 CRIMP HOUSING, 1 ROW, 5 WAY
1593522 10 .2700 2226B-10 CRIMP HOUSING, 2 ROW, 10WAY
2291047 is the number for rolls of 30 meters of 28AWG wire, black, but it's kind of expensive at around 14$ for one roll. I needed black with as little text as possible on the wire itself for some computer case cabling mod so the price was not an issue.
If you only need small lengths you can cheat and buy from eBay or pc stores IDE cables for under a dollar a piece, and you basically have 80 x 40-60 cm and 80 x 20-30cm (smaller strip between the two ide connectors) of awg30 cable. For example, here's a set of 2 cables for 4$, 3.5$ each if you order at least 3 sets.
For hobby at home you can also cheat and get stranded network cable (for flexibility).. you get 8 insulated wires inside (i don't know the exact gauge, maybe awg24?) AND they're all different colors for way under half a dollar a meter. The cheaper cables are copper clad aluminum but for small projects aluminum or copper won't make much of a difference.
For example, monoprice has 305 meters (1000 feet) of stranded network cable for 85$ : http://www.monoprice.com/Product?c_id=102&cp_id=10233&cs_id=1023304&p_id=886&seq=1&format=2 (http://www.monoprice.com/Product?c_id=102&cp_id=10233&cs_id=1023304&p_id=886&seq=1&format=2)
Be careful not to get solid CCA (copper clad aluminum) cable if you go this route, the aluminum will break easily with bending of the wires.
Farnell.com is element14.com or Newark.com in US. Codes above should work on newark or farnell or element14 when the site works.
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I have a drawer full of various IDC ribbon cabling - old floppy, ide, CDROM, scsi, serial/parallel fingers... make the interconnect to fit what's available in the drawer.
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And for those not in the UK area you can get engineer products direct from japan via rakuten
http://global.rakuten.com/en/store/monju/item/800-pa-20/ (http://global.rakuten.com/en/store/monju/item/800-pa-20/)
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Just don't buy the velleman VTECT2 (http://www.velleman.eu/products/view/?country=es&lang=en&id=372846). It looks good on a photo, but is junk.
Maybe the orignal VTECH (http://www.vellemanusa.com/products/view/?id=350879) was better, I remember I once had a good Velleman crimper, why I bought one again, but the VTECT2 is a waste of money.
Edit: No, the VTECT is for cord-end, not for terminals. I wonder what the model was I used to have 2 decades ago. Or whom I lend it too.
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Thanks, guys!
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Can IDC cable of n width be reliable turned into n-m width cable? Like by "peeling off" a piece?
If so, I could just buy a bunch of 2.54mm pitch, say 20pin cable and use it to make 4, 5, 8, 12 pin cables as necessary.
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In my experience, yes. You can reliably tear off one or more wires if you first cut-in a few mm.
Though I could imagine there may be some plastics that will not tear nicely, I have so far not seem them on any ribbon cable I have held, they always tore nicely without exposing any wire core.
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Can IDC cable of n width be reliable turned into n-m width cable? Like by "peeling off" a piece?
Yup. Do it all the time.
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Whether I put sockets on the board and make pin cables or put pins on them and make socket cables, it's a PITA.
I know I could buy appropriate-sized ribbon cables with connectors on them, but since the number of pins I need is never the same, nor do I need the same lengths, etc, it seems stocking a variety is expensive and hassle-filled. And you never have in your box exactly what you need, so it's back to DigiKey to pay shipping again.
Put pins on the boards, not headers (Putting headers on the board became popular with those stupid Arduino stuff ...).
Settle on a few typical pin numbers per connection, i.e. if you need seven connections round up to your nearest "standard" size like 2x5. Keep IDC headers of those sizes you settled on in stock. And keep a roll of 20 or 40 wire ribbon cable.
You don't need any special IDC header crimping tool. At least not if it is for hobby purposes. You can simply press the headers onto the ribbon cable using a vice. The key to assemble IDC headers is that the pressure needs to be equally distributed when you press, and you can manage this easily with a vice slowly tightening it
For the few special cases where you need non"standard" connections have a few of those ready (only an example, many other sellers on eBay): http://www.ebay.com/itm/40PCS-Dupont-wire-20cm-cable-Line-color-1p-1p-pin-connector-/400651670622 (http://www.ebay.com/itm/40PCS-Dupont-wire-20cm-cable-Line-color-1p-1p-pin-connector-/400651670622)
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One solution I have found are these female-female "DuPont" cables from many vendors on eBay. The ribbon cable has individual 1-position female sockets and you peel off the width you need. They will stay put on square header posts – a bit of force is needed to pull them off.