generic backplane ? - Page 1
Forum section: electronics / projects

author: RustyShackleford
author_rank: Regular Contributor
timestamp: November 26, 2017, 07:01:27 am
content: I'm looking to build a small system that consists of 8-10 small identical boards. Boards will be 4"-square (at most), and need to be spaced 1.5-2" on-center. There are less than a half-dozen signals (including power and GND) that need to be bussed across all boards, and each board needs to have about 3 dedicated connections (that only go to that board). No board connection will carry more than an amp. The power/GND busses need to carry up to 8 amps or so.Designing and fabricating my own backplane will be pretty expensive (since it needs to be 12-20" long and at least 4" wide). I'm wondering if there's any sort of "generic" backplane/backplane-connector system that is available for a need such as this ?

author: German_EE
author_rank: Super Contributor
timestamp: November 26, 2017, 09:25:33 am
content: Get yourself some Veroboard (Vectorboard / Matrix board) with the copper strips 0.1 inch apart, then use standard 0.1 inch connectors on the PCBs and your 'backplane'. I've seen pieces for sale up to 20 inches long.Bonus: you can use tracks in parallel for better current handling.

author: daqq
author_rank: Super Contributor
timestamp: November 26, 2017, 09:39:29 am
content: Well, you can go with a cable "back plane" - you can use multiple IDC connectors on one long flat cable. You can use this kind:http://cvilux.manufacturer.globalsources.com/si/6008800528260/pdtl/IDC-connector/1003334023/Ribbon-Cable-Connectors-IDC.htmif you want to mount the connector in a stationary system and pull the cards out. Or you can just use regular connectors and plug and unplug the bus as you would a standard cable.

author: bd139
author_rank: Super Contributor
timestamp: November 26, 2017, 10:02:44 am
content: +1 for IDC cable backplane. Works a charm. As used in the RM 380Z series of computers.

author: RustyShackleford
author_rank: Regular Contributor
timestamp: November 26, 2017, 09:27:20 pm
content: Anybody got another link for the IDC connectors (with mounting flanges) ? The one @daqq gave seems to be for large quantities (since they don't list prices and want you to "inquire"). This one looks reasonable:https://www.mouser.com/Search/ProductDetail.aspx?R=583718-1virtualkey57100000virtualkey571-583718-110-positions should be plenty, and I like the 0.1" spacing (instead of 0.050") though 0.1"-pitch ribbon cable looks harder to find.For the 3 un-bussed connections to each board, I suppose I could peel off 3 strands from the ribbon cable (at each board), or simply solder 3 wires.

author: C
author_rank: Super Contributor
timestamp: November 26, 2017, 09:44:37 pm
content: You are missing a simple fact.A ribbon cable connector is two rows of pins.If pins are on 0.1 spacing then you need 0.05 space ribbon cableOne row of pins on connector connects to odd wires in ribbon cable.One row of pins on connector connects to even wires in ribbon cable.there are ribbon cables for 0.05 space connectors this gives 0.025 space ribbon cable.For the unbussed just remove some wires from ribbonyou could then use these removed ribbon wires for special connections to a connector.For PC computersthe floppy drive cable is for 0.1 connectors and has 0.05 space cable.first IDE drive cables had 0.05 space cable.to get speed of last generation they added a ground wire between original wires and used 0.025 cable.Old computer could give you the ribbon cable you needIf you want to talk really fast, put a ground wire between signals on ribbon cableUse one row of pins for signals and other row for ground.most ribbon connector pins are rated for 1 amp.If close to 1 amp power , use more pins.It is a good idea where you can to have ground signal ground on bus anytime.

author: daqq
author_rank: Super Contributor
timestamp: November 27, 2017, 07:27:10 am
content: A quick search on farnell:http://uk.farnell.com/3m/4640-6000/header-idc-lugged-40way/dp/469191Edit: Or there are IDC DSUB style connectors:http://uk.farnell.com/te-connectivity-amp/1658615-2/plug-idc-d-plastic-25way/dp/1098383