I have just received a small(12mmx22mm) motion sensor module which is all surface mount and has very small edge pads for interconnections. The module is reasonably expensive and for prototyping and just getting it going I would like to connect it up without soldering it down. My thinking is to make some small springy bent L edge connectors sort of like shown below and solder these on to a copper clad board as a breakout

   \                /
  _/................\_              ....... Module
  -------------------           ----- PCB

Now I am no watch-maker, I have tried similar things in the past and whilst in my head they always look professional, the end result is usually a lash-up. So are there any other ideas of how to do this or any tips on forming tiny parts, it is all going to be hand made and hand soldered. Not all the pins I need to connect are on one edge and the big concern is accuracy of making and positioning the spring connector so that they both hold the board and make reliable contact.

 

I would use zebra strip connectors (Google it) but that needs PCB pads that match your board so it's a chicken and egg solution.

A picture of the board or link would help.

 

google 'header pin connector'
you csn drill small holes for the pin and solder them. you could silicon the pins snd connect with small wires instead of drilling. using pins makes the board removeable

 

Thanks those elastomeric connectors look like the right sort of thing but none of the regular suppliers seem to stock them. Making a PCB of the right dimensions is not a problem in fact I drew up a part in Eagle last night before I got to thinking that soldering it initially is probably not the best approach. I'll post a picture this evening.

But... what I am now thinking is to make my own elastomeric connector - solder loops of wire to pads on a PCB at the correct spacing for the module contacts, embed these in something like bathroom silicone and press the module down onto this once the silicon has set.

 

pressing against metal and relying on the spring tension to keep the connection secure will work for awhile. eventually the metal sets in the new position and all the spring tension disappears. FYI

 

I know what you are getting at but it's all about elastic vs plastic deformation, the shocks in my car haven't set in a new position yet. As I said this is just for initial trials before the unit gets permanently fixed into the final project.

 

If you measure the pad size, you could check out the various insertion pin/sockets for miniature & sub-miniature in line connectors, if you find a suitable type, a solid or flex wire could be attached as it would be in a connector.
Digikey is one of the best sources.
Max.

 

Hi,
You can get this type of compression 'pin contact', used on auto testing PCB's.
http://www.coda-systems.co.uk/catalog/ATE_Probes_and_Receptacles.html

E
Look at the 'How to Use' / Fitment link on that page

 

be careful using silicon calk on electrical connections, chemicals in it can corrode some metals.

 

I would use zebra strip connectors (Google it) but that needs PCB pads that match your board so it's a chicken and egg solution.

Be warned that there are 2 types of elastomeric connectors. The ones used in LCD modules are carbon loaded and have a high resistance. Others have "needles" and have low resistance. You may not be able to the carbon ones. You can take apart a broken LCD character or graphic display to get some zebra strip to play with.

Edit: I should have mentioned that the strips must be very well supported or they flop over and don't work.

 

Thanks all I'll investigate those suggestions. As promised, here's some pictures

 

It is a little hard to tell the center-to-center distance. It looks around 3 mm. If it is actually 2.54 mm or 4 mm (or some nice multiple), then a standard pinheader will work with solder.

John

 

It is 3mm, and in one case 5.5mm, extract from datasheet attached and here's a link to the DS
http://www.pnicorp.com/download/527/434/Sentral MandM Technical Datasheet_rG.pdf

 

The pads are not horribly off a 0.1" grid such as a breadboard. I took the pad layout on sheet 28 and sketched it in autocad and pasted that on a breadboard grid.

Not too bad a match, and you can use the breadboard to hold some fly wires; I use 30 AWG for stuff like this.

 

That's great, thanks for taking the time, another set of eyes is always a good thing, I think I was a bit bogged down in 2.54 != 3.0

 

One last thing: (two actually) when I say "breadboard" I mean the ones I use which that are a sea of plated thru holes on 0.1" centers, not a solderless breadboard.

But do be careful there are no features on the device's backside that could be shorted by the unused pads.

 

Thanks, may well make up a little board and as you said earlier just connect it with short flying leads