Connectors for modular system - Page 1
Forum section: electronics / projects

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 08, 2016, 02:16:01 pm
content: I am making a system of modules that need to connect together in a way so that adding or removing a module is easy.There will be two different 'end' modules which need a male on one and a female to match on the other. 'Middle' modules will have a both male and female connectors to line up with the ends and each other.The idea is that the modules will be plugged together to form a line, say left to right, so you can unplug a middle module and either remove it or add in another one.The challenge:1. Power supplies are 100v DC and are 15A maximum so the pins need to be either high current or enough of them.2. Only two pins need to be high current, the others are for data3. I actually only need to move 6 signals but it would be nice to have a few more.4. Small enough to go vertically in a 1U box - not a show stopper if not but it gives an idea of the size5. The power end has to be shielded so no one gets zapped when some unsuspecting bod unplugs it when there is power applied.6. Consumer prices rather than military!I was thinking about DIN41612 but they're a bit big.All suggestions gratefully received

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 08, 2016, 02:52:24 pm
content: Thank you for the suggestion blueskull - you are absolutely right.I missed out that they need to poke out / in in a way so that they are inside the enclosure of the module. The module is sealed up apart from the connectors.That might still be possible with 0.1" but I can't quite see how to make it mechanically sound. I'll add a couple more things to the list ( my first time asking so please bear with me )7. Need to overcome a 1/8" enclosure thickness8. Mechanically sound so the pins don't get bent by miss-alignment before pushing together...

author: H.O
author_rank: Frequent Contributor
timestamp: June 08, 2016, 05:05:58 pm
content: How about Molex MicroFit?Certainly more expensive than .1" pinheaders but they are keyed, latching and capable of more current per pin. Check the datasheet for derating factors etc.

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 09, 2016, 06:18:52 am
content: Thank you blueskull - I understand what you meanI'll need to work out the mechanics of that to make sure it will actually go togetherMy only reservation, and it's not a big reservation, is that the pins can be bent when the modules are disconnected / moved aroundand thank you H.O. the molex microfit idea is also a good one; except that latching (not sure if they do a non latching version) would mean that the modules couldn't be separated once connected together. Something like that was what I was imagining before the blueskull idea (which is tempting)

author: H.O
author_rank: Frequent Contributor
timestamp: June 09, 2016, 07:40:33 am
content: Certainly the latch will/should end up outside the enclosure?Are you saying that the outside of the enclosures should be right up against each other once mated?You could of course just cut off the latch....There's also the DSUB type connectors with different pin sizes but then you're getting into the "military price range"....The thing with pin headers is that even if you put the powersource on the socket (which you should of course) you can still "get to" to bare pins when they are partially mated. For this reason I'd say you need to do the opposite of what blueskull suggests, that is let the female header protrude outside its enclosure and have the male pins slightly recessed in its enclosure so that there's no way to get to the pins once the two module makes contact.

author: ruffy91
author_rank: Regular Contributor
timestamp: June 09, 2016, 09:16:11 am
content: I think 0.1 female right angle headers (protruding out the case) and shrouded male right angle headers (recessed inside case) should do the trick.Gesendet von meinem JAZZ mit Tapatalk

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 09, 2016, 11:06:52 am
content: Thank you blueskull, H.O and ruffy91Just to cover the H.O point about latching; yes the modules push together so that there is no gap between them and then there is a 'nifty' way to stop them coming apart (that I haven't thought of yet) - the idea being to make a solid line of modules you can pick up and swat flies with (or whatever you fancy; which I realise is an anti-fly statement but am only trying to convey the idea)blueskull is right again, the female versions are nearly in hen's teeth country, certainly compared to the male ones (unless someone knows better). I think I must have entered some sort of time warp because those female ones used to be easy to get, in all sorts of numbers of pins.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: June 09, 2016, 11:09:26 am
content: I don't much like 0.1" pin headers when mechanical issues are important. If I were you, I'd leaf through Samtec's catalog; they have plenty of solutions that look like they would be good fits for you. ThePETC/PESC seriesmight be a good place to start.

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 09, 2016, 11:21:00 am
content: sane scientist, thank you, now that's the sort of thing I was dreaming aboutI will have a trawl through to find prices - 40A! imagine the bang potential of that at 100v

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 09, 2016, 11:52:09 am
content: Ah,Those certainly are lovely connectors madscientist and I am sure that they are worth every cent but unfortunately at £6 each are a bit out of my league (£12 per unit)They are also 2" long which is like DIN41612, a bit big for preference.Maybe tackling it as two connectors, one for two power pins and the rest small?

author: H.O
author_rank: Frequent Contributor
timestamp: June 09, 2016, 06:45:40 pm
content: Another idea:Get a dual row female header with longer pins, as thick pins as possible (wire wrap headers might be ideal) and mount it on the edge of the PCB (one row soldered to the top, the other to the bottom) with enough clearence between the PCB edge and back of header to protrude enough thru the enclosure.

author: Someone
author_rank: Super Contributor
timestamp: June 10, 2016, 05:07:30 am
content: Quote from: H.O on June 08, 2016, 05:05:58 pmThese are one of the few cheap options that will keep both genders shrouded, and they come in solid through hole versions that don't have the latch. Seems like a perfect fit.

author: mariush
author_rank: Super Contributor
timestamp: June 10, 2016, 07:30:04 am
content: Have a look at JST JQ connectors :http://www.jst-mfg.com/product/detail_e.php?series=149It looks like it has a sort of locking mechanism but maybe if you pull the modules hard enough, the connection disconnects and the plastic lasts for at least a few cycles.May also want to have a look at JST LEB ... it's a connector for LED circuits but it looks nice :http://www.jst-mfg.com/product/detail_e.php?series=601Downside is that it looks like it's only for 2 positions maximum, so you'd need several of them for the six signals and power and i'm not sure if it's smart to use surface mount soldered parts for this.Think about what happens if two modules are interconnected and they fall down on the floor, your product should at least have some plastic or metal pins/protrusions/bumps/whatever with holes or depressions on the opposite module so that when the modules are linked, 2-4 of these would lock the modules in place and take the mechanical stress instead of the connectors.Btw .. for the signals .. if the data rate is not high and it's not bidirectional, have you considered using some very narrow angle LEDs for one side and optical sensor for the opposite module? This way you'd have a simple rectangle cutout with some glass/plastic on both modules covering the leds or sensors. Basically, you'd make a bunch of optical isolators, it's common in some multimeters for example, to isolate serial data between PC and multimeter.

author: Chris Mr
author_rank: Regular Contributor
timestamp: June 10, 2016, 10:31:17 am
content: The MicroFit are nice enough I agree someone, and probably high or on top of the list for fully shrouded.mariush, thank you for your suggestion too. I especially like the idea of making our own opto isolators. The data rate is a bit high, just under 100Mb/s but the distance is tiny and darkThere's also the option of using poke-out PCB via ferrite to do something similar. Like the separateable transformer used in electric toothbrushes. That'd be neat.So that left hook idea, mariush, could mean we only need 2 high current pins - like short banana connectors