looking for a way (connector) to interconnect identical pcb's - Page 1
Forum section: electronics / projects

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2018, 11:45:49 am
content: Hi folks,for an upcoming project, I would like to interconnect pcb's that are similar.something you can add identical pcb's each time you need itso I need to have one female and one male connector, that are horizontal and at the edge of the pcbthey must support mains voltage (as well as small voltages also)I would like not to use wires between the pcb's.what are my options for this ?thanks.

author: Benta
author_rank: Super Contributor
timestamp: November 02, 2018, 01:25:05 pm
content: An idea of the size would help.

author: max_torque
author_rank: Super Contributor
timestamp: November 02, 2018, 01:44:39 pm
content: Important factors to be considered (in no particular order right outta my head)1) Number of mate/de-mate ops (some connectors not designed to be connected and disconnected often can have surprisingly few cycles before their resistance increases2) Voltage levels - do you need to protect the operator for any "High" voltages (anything over 50Vdc is typically considered "high" from an H&S perspective)3) Environmental/sealing - do you need any? bare pins, waterproof, vibration resistance etc etc4) Keying - will all connectors be able to fit into all sockets? or will some need keying to ensure they only get inserted where they should5) Mechanical strength and support - relevant to 1) also. How strong and does the connect need to interface (be supported by, or sealed too) the enclosure in which the electronics may sit6) Current carrying requirement7) ESD protection (touch proof pins etc)Volume - how many do you need and how are they being assembled9) Cost10) Signal bandwidth and shielding requirementsAs you can see, just asking "what connector" is not really enough.Solutions range between 1 cent bare pin headers and $1000 space rated interconnect systems depending on the answers to those ^^ questions

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2018, 01:55:08 pm
content: Quote from: Benta on November 02, 2018, 01:25:05 pmbetween 3 and 10 pins. 2.54mm spacing or eventually 1.27mmI think 2.54mm for mains pins spacing is the minimum ?

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2018, 01:58:00 pm
content: it is to transmit mains and some signals (i2c, spi, or low frequency signals) from one pcb to another (same pcb to another if needed)no vibration, waterproof not needed, low volume hobby use.they won't be connected/disconnected often, only during first tests after that they will stay forever connected.

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2018, 01:59:29 pm
content: something like this is ok for me, but I want no screw and no wire, only a male and female connector

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2018, 02:01:51 pm
content: and yes I want to protect the operator from mains voltages, so the pins must not be exposed.( except under the pcb of course)

author: olkipukki
author_rank: Frequent Contributor
timestamp: November 02, 2018, 02:35:26 pm
content: Quote from: max_torque on November 02, 2018, 01:44:39 pmIMHO, very well highlighted how to choose and narrow down selection from a million and one optionsI would add an extra item to above list 11) Availability

author: mariush
author_rank: Super Contributor
timestamp: November 02, 2018, 04:25:08 pm
content: You can spend hours looking on Digikey and other sites at board to board connectors, for example :https://www.digikey.com/products/en/connectors-interconnects/rectangular-connectors-arrays-edge-type-mezzanine-board-to-board/308you should also consider Flat flex cables and connectors, you can buy cheap ribbon cables in small lengths (like 10cm for example) and connectors are cheap in volume, cheaper than edge or board to board connectors. And, you should be able to easily carry both mains and low voltage signals as long as you leave some spacing on the ribbon cable between them.you can get a 30 contact ribbon cable for less than a dollar and connectors are below 0.50 in quantity.

author: Nusa
author_rank: Super Contributor
timestamp: November 02, 2018, 05:26:04 pm
content: Card edge connectors would be another way to go. Either in a backplane setup or a side-to-side chain arrangement.

author: nctnico
author_rank: Super Contributor
timestamp: November 02, 2018, 05:44:53 pm
content: Quote from: kripton2035 on November 02, 2018, 01:59:29 pmWurth has PCB male / female versions of these plugs. They call them reverse gendered.http://katalog.we-online.de/en/em/TBL_3_81_3103_HORIZONTAL_PCB_HEADER_W_FLANGES_6913103400XX

author: Ian.M
author_rank: Super Contributor
timestamp: November 02, 2018, 07:06:20 pm
content: Quote from: kripton2035 on November 02, 2018, 01:55:08 pmThe pad width subtracts from that 2.54 mm spacing, so its extremely unwise, and probably dangerous to put mains on a 2.54mm spacing connector. Its possible to omit one pin (remove all metal parts) in the connector between Line and Neutral to get 5.08 mm spacing which with narrow PTH pads will let you maintain 4mm clearance, but you'll probably need to omit more than one pin to get adequate clearance between mains and low voltage circuits. You may also need to slot the PCB under the connector to get adequate creepage distances.If you are omitting pins anyway for clearance, its worth putting insulating plugs to block the unused positions in the female half connector to key it so it cant be mated with a similar connector with a different arrangement of mains and low voltage contacts.

author: max_torque
author_rank: Super Contributor
timestamp: November 03, 2018, 07:16:02 pm
content: IMO, even for hobby use, putting potentially lethal voltages in the same connector as low voltage signals is bordering on negligent. Certainly, in the (extremely unlikely) case of someone being injured, in the UK at least, you'd expect to be pulled up in front of the courts, potentially getting a fairly lengthy prison sentence!Put the mains, on a separate, suitably rated, and suitably insulated, and very well labelled connector(s)HV voltage 4mm banana sockets (touch proof and colour coded) are one (good) optionOr use "Booted" faston spade terminalsYou can thank for for saving your life later........