Designing connector between two PCBS - similar to SD card

Hi Everone

I would like your opinions & ideas on a problem I am having.

I am currently designing a prototyping platform (everything is still very beta, but I might post some general info on the project in a separate thread.) The system is modular, and basically consists of a motherboard, with multiple modules which you can connect to it. There are ~ 11 - 15 signals (as I said, things are still beta.) which need to be connected between a module and the motherboard. Currently we are connecting things with regular pins, like the Arduino shields. However, the modules are so small (33mm x 33mm, smd components), that almost 30% of their bulk is created by these connectors. I am currently looking for alternate methods of connecting them.

Does anyone have any suggestions?

I really like the way SD cards connect. I was thinking that it might be able to create a similar system. Does anyone know the name of the little connectors in the SD card connector? (I attached an image in which I circled what I am talking about.) I am speculating, that if you could get those individually, that you could create your own sd-card-style connector. (this also has the benefit of ensuring that power connects before logic level signals connect, which we don’t have at the time.)

Alternately the MMCplus has a layout that would work for our system. However, I was unable to find anyone offering connectors for MMCplus. I am either using the wrong search-term or… they are no longer being fabricated or they are some ultra secret licence? (I was searching on and similar sites)

here is a picture of what I am talking about:

Thoughts and Ideas would be appreciated… and if someone knows the name for that tiny part I am looking for, that would help me heaps as well.




Could you reduce the number of pins dramatically by using something like spi? carries whole lines of small connectors. Browse here
Here’s a pic with 1.5mm pitch connectors I am working on now.
The RF module plugs into a header with 0.05" spacing.

Thanks crossroads. This is going in the right direction. Browsing their website now.

Does anyone know what connector they use for the mama-shield?

@bill - pin number is determined by a bunch of factors - we need some parallel communication and have various power options. We can reduce by a couple of pins, but that would not change the initial problem.

This I like:
However, I need it to be about half the size, and I only need 25% of the pins.

Other alternative is this guy:

Still open for other suggestions.

If you put a couple of those SCG connectors from JST side-by-side, you could have a dozen contacts in a small space.

But beware of attempts to "hot-plug" in that configuration, because you'd have contacts sliding past things they shouldn't be connected to.

I generally don't like "push-push" SD sockets in embedded systems: too much chance for shock or vibration to pop something loose. If you go with SD, I'd suggest looking for the non-spring-loaded kind used in many USB card readers.

I'm just the opposite - I like the push-push for SD.
My Sony Vaio has that, works great. So does my Canon camera. I pop the card back & forth all the time for pictures, way faster than downloading via cable. Also does not use up battery.
When it's clicked in, its in.

My wife's HP does not - have to yank the card out. Always awkward.

Were we talking uSD also? Have not seen anything but push-push for circuit cards. Push/pull in uSD/SD adapter only.