Comments on: Opinions Wanted: Connectors for LED Driver

By: Keith Neufeld

Keith Neufeld — Sun, 21 Mar 2010 17:05:07 +0000

Asmodeus, thanks for pointing out the obvious technique of separate holes for the breadboard and off-board connections! That’ll work marvelously and the Tyco connectors you found are perfect.

By: Chris

Chris — Sun, 21 Mar 2010 16:30:58 +0000

Futurlec sells the connectors/pins/etc that you want. I’ll vouch for Futurlec, I’ve ordered 3 orders from them, each over $150 and they’ve all arrived in about 2 weeks with their standard shipping, you can pay more and get them faster.

http://futurlec.com/ConnPolHead.shtml

Only issue I ever had was they delayed shipping my order by 5 days to get 1 part in stock, I followed up and told them to ship without the part and they had it out that day.

By: Eric

Eric — Sun, 21 Mar 2010 16:22:05 +0000

A few thoughts:

1) For input, you could consider putting a FW bridge on the input so that you can plug it in either way. Extra cost though. Or, you could make it a three-pin connector, with ground in the middle and Vcc connected on the board to either side. That gives you an unpolarized connector – as long as they get the pins aligned, it wors.

2) For the LEDs, you could consider doing the same thing, though that would require more board space. I think it’s okay if the LEDs just don’t work if you hook them up backwards. You could also consider a 2x connector.

By: Asm

Asm — Sun, 21 Mar 2010 14:44:22 +0000

Hm. But you don’t have to widen it a whole lot; a single millimeter is enough, if you want to keep the same hole-to-board-edge spacing.

Did a quick mockup of the difference: http://dump.gpio.org/headerwidth1.png

So if you instead use a pinout like this, which will allow both .100″ spacing for breadboarding as well as these connectors:

http://dump.gpio.org/fixedspacing.png

Ough to work, and doesn’t really take much more space.

If you do end up using them: Sure, I’d love one. I’ve got some 3s16p LED arrays which should be right on target, and I was planning on building a driver for them at some point in the future (http://www.dealextreme.com/details.dx/sku.13190).

By: Keith Neufeld

Keith Neufeld — Sun, 21 Mar 2010 14:10:37 +0000

Drat. Asmodeus, the female housings have sidewalls thick enough that these won’t fit side-by-side on adjacent male pins. I’d have to leave a space between two-pin LED connectors — and to keep this possible to plug into a breadboard using different connectors, it’d have to be a .1″ space.

I’m staring at the datasheet and I just can’t get around that.

I’ll look at widening the PCB — it may be worth it in order to use these connectors.

By: Keith Neufeld

Keith Neufeld — Sun, 21 Mar 2010 13:59:38 +0000

Cham and others — I was already intending to provide at least one extra crimp pin per connector. Since the pins are relatively inexpensive compared to the rest, I could provide two or three each.

Devlin — I like IDC ribbon cables, but I don’t recall seeing them for only two pins. I want the three LED strings to be independently pluggable, not attached together into a three-string block out of necessity.

Asmodeus — you found exactly the connector I had in mind when I searched Digi-Key, and I didn’t run across them. You now have the connectors to beat! (And a driver or two owed to you once they’re assembled, if you’re interested.) Thank you!

By: Asm

Asm — Sun, 21 Mar 2010 10:57:03 +0000

Links (didn’t want to stick them in the other comment due to the spamishness):

Crimp pins: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A100453CT-ND
2-pin header: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A19450-ND
2-pin housing: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A99613-ND

3-pin header: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A19451-ND
3-pin housing: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=A99614-ND

By: Asm

Asm — Sun, 21 Mar 2010 10:22:47 +0000

Cost savings, my favourite topic!

Well, Sparkfun also has very cheap polarized 6-pin headers – just search for “ICSP” on their site. 8 cents/piece for 100+.

Anyway, a cheaper option: Use 3-pin polarized connectors for input power, and three separate 2-pin polarized connectors for output.

Input: A99614-ND housing (.0868), A19451-ND header (.0869), 2x crimp pins (.0222/piece), for a sum of 22 cents.

Output: A99613-ND housing (.0412), A19450-ND header (.0631), 2x crimp pins (same as above, .0222/piece), for a sum of 15 cents/piece, and since you need three, 45 cents total.

So per box you end up at 67 cents for connectors, and you can’t mistake input and output connectors either. Not too shoddy. Note, I’m using pricing for 100+ connectors, but you can get all of these in single-unit quantities too (for not much more).

Good luck!

By: Jean-Claude Wippler

Jean-Claude Wippler — Sun, 21 Mar 2010 10:17:07 +0000

Asking people to put 3x 2-pin plugs in a 6-pin one might defeat the purpose of polarized: if you put them in wrong, you will connect things in reverse anyway.

Another way to prevent reversed connections is to connect only 2 pins of a 3-pin header. Then you could use simple unpolarized 0.1″ headers.

By: Devlin

Devlin — Sun, 21 Mar 2010 08:25:31 +0000

I can think of a few things:
IDC connectors like the MakerBot’s motherboard to motor driver rainbow cables.
Look at how a lot of fluorescent ballasts do it:
Some use screw terminals and just print stickers to label the terminals. Some even come with the ability for the screw part to unplug from a male header on the board.
Similar to the screw terminals, is a terminal that is spring loaded and has to be pushed down in order to insert a wire.
Wires soldered directly to the board. The installer (customer) has to connect each wire to the appropriate wire with wire nuts.

Other than that, you could use connectors with twice as many pins as are needed and only use the odd (or even) numbered pins, leaving the remainder unconnected on the board (not even grounded). This would allow a non-destructive reversed connection.

Maybe you could make some parametric open-source 3-D printable connectors?

Hope this helps. Good luck!