Low/zero-profile programming header ideas? 2.54mm pitch spring contact arrays? - Page 1
Forum section: electronics / projects

author: rs20
author_rank: Super Contributor
timestamp: June 14, 2015, 07:47:04 am
content: For many of my projects, the programming header is the tallest thing on the board. So I had the idea of routing the programming lines to the edge of the board, and making a one-off adaptor with a card edge connector* on it to program it. I like this idea in that there's a $0 cost per project, and it's zero-profile. However, there are some disadvantages with the idea; it might be inconvenient to route all the way to an edge of the board, it's highly nonstandard if I decide to share my designs, KiCad doesn't support component footprints that incorporate board cutoutsbecause someone though it'd be more useful to have a flawless 3D view than a useable EDA package, etc. So I'm wondering if anyone has any other clever ideas that meet the spec of being (near) zero-profile.In particular, I was thinking it would be awesome if you could have a standard 2x5 programming (JTAG) header on the board, but leave it unpopulated and connect to it with some kind of funky bed-of-nails springy connector that you just press down on the footprint, or maybe tiny versions of banana plugs that actually fit through the through-holes in the footprint in the same way that normal banana plugs press-fit to the 4mm holes in power supplies. But I have no idea if such things exist in the real world? The good thing about this is that some users could just choose to populate the part like a normal person.I can imagine just poking a standard 2.5mm male header through the holes in the footprint and hoping for good contact, but that seems like it'd be unreliable?Any thoughts / war stories appreciated* e.g.:

author: dom0
author_rank: Super Contributor
timestamp: June 14, 2015, 08:07:33 am
content: http://www.tag-connect.com/

author: kripton2035
author_rank: Super Contributor
timestamp: June 14, 2015, 08:07:49 am
content: use pogo pins ...http://protofusion.org/wordpress/2013/05/open-hardware-pogo-pin-programmer/

author: rs20
author_rank: Super Contributor
timestamp: June 14, 2015, 09:35:35 am
content: Awesome, thanks! Starting from those links, I found somepogo pins on eBaythat'll apparently fit right into a standard 2x3 / 2x5 IDC cable, and endow it with springy goodness. No need for an adapter board at all, and I can use a dead standard footprint! Win!Thanks again!

author: con-f-use
author_rank: Unknown
timestamp: June 14, 2015, 11:44:27 am
content: I use thetag-connectsystem.The variant with "legs" says in place but requires more board area.I find the one without "legs" more useful. If you need it to stay in place, I use this:

author: Psi
author_rank: Super Contributor
timestamp: June 14, 2015, 12:15:57 pm
content: I also use tag connect.It's not the cheapest connector, but at least the product side is free, just a PCB footprintConnector is like US$30-40

author: amyk
author_rank: Super Contributor
timestamp: June 14, 2015, 12:51:25 pm
content: Just embed a few pogo pins in a block of epoxy...Depending on the package you might not even have to place any extra traces for the programming pads if you just use a test clip on the IC itself.

author: alank2
author_rank: Super Contributor
timestamp: June 14, 2015, 01:16:55 pm
content: I just use 1x6 "inline" isp instead of 2x3, in 100mil and 50mil. A small adapter is all you need and it is cheap.PCB side is just through holes - here it is underneath a tiny1634 soic: