Stackable Headers for Propeller Platform Modules
jazzed
Posts: 11,803
In the PPLA thread ...
I already have buyers lined up for half of the 10.5mm tail the the parts, but I may be sitting on more parts than i need after that. One way or another, I'll make good on my previous commitments.
Here's what I'll do: I'll offer the stackable headers at $.20 each for the 4 pin headers and $.40 each for the 8 pin headers. This would make user cost $2.00 per Propeller Platform module (single row both sides). A 25% discount will be given for 100 piece orders. These numbers are competitive with Sparkfun's parts. If anyone is interested in this deal, please let me know.
I'll order some of 15.5mm parts and see if they can be used.
I've started this thread to keep from polluting Brian's PPLA thread.
I've had my eye on the 4uconnector.com parts since January and have an account. My initial plan was to order 1000 each of the 4 and 8 pin 10.5mm tail connectors. The mechanical stackup should yield an 8.9mm (0.35" inch) between each board. The 15.5mm tail parts would yield 0.54" between each board which has about the same clearance as a current PropellerPlatform sandwich.Ding-Batty wrote: »This site only has two sizes with that length tail: 6-pins (Item number 19874), and 8-pins (Item number 19875). I think the ones with 10.5mm tails would not be tall enough (unless you used two of them stacked to get enough height).
I already have buyers lined up for half of the 10.5mm tail the the parts, but I may be sitting on more parts than i need after that. One way or another, I'll make good on my previous commitments.
Here's what I'll do: I'll offer the stackable headers at $.20 each for the 4 pin headers and $.40 each for the 8 pin headers. This would make user cost $2.00 per Propeller Platform module (single row both sides). A 25% discount will be given for 100 piece orders. These numbers are competitive with Sparkfun's parts. If anyone is interested in this deal, please let me know.
I'll order some of 15.5mm parts and see if they can be used.
I've started this thread to keep from polluting Brian's PPLA thread.
Comments
Current specification uses 3M 2340-6211TG pin headers, they extend .408" off the bottom of the board (.308" of pin + .100" for the plastic frame that holds the pins together).
Using those headers, empty space between boards mics out at .508.
With the 12.5mm stackable headers (.492"), you lose 60 mil through the board and the pins will extend .430". Adding the sockets and you get .530".
With the 12.5mm stackable headers, there's enough clearance, and the height is almost exactly the same. 10mm headers will mostly work, but it will bang into RCA jacks. It also won't leave room for TH stuff on top of the power jack or screw terminal.
I like the 21x2 with 13mm tails, it would be easy to just remove the extra pin.
The headers I have that used for the Arduino boards have 10.5 mm tails, not the longer ones. When stacked together, the top header surfaces are 12.7mm apart. Subtracting the thickness of the board, and a little for mounting slop matches what I measured below.
I have the long-tail headers on the GG PP SDRAM board, and on the GG PP Prototype board. With them connected together, and on top of the original PP board (kit, through hole) I measured 11.1mm from the top of one board to the bottom of the board above it, in both combinations. This is high enough for the upper board to clear the power barrel jack on the PP board.
I don't have any boards with an RCA connector for comparison.
So, 10.5 mm might be a little short for some boards, but I can always stack another set of female headers on to get an additional 12.7mm of height, when I need it. But longer pins would be easier, or just put the board with tall components on the top of the stack.
Thanks for following up.
--Steve
Let me know if you settle on the 1x21 8.5+10.5mm as I could cut them down too.
I am also doing RA 1x13 male #17366 or 1x20 male #00637 and female #00629 if you are interested.
As a first approximation, if 10.5mm tails give 11.1mm clearance, then 10.5 + 2.5mm == 13mm tails would give 11.1 + 2.5mm == 13.6mm clearance. (Use a delta of +0.6mm clearance.) So, to clear 12.7mm you would need 12.1mm tails as a minimum.
However, it's more complicated than that. On looking at the 4uConnectors mechanical drawing for the 10.5mm length female header, all of the relevant dimensions are +- 0.20mm or +- 0.25mm, so a "10.5mm" tail might be 10.25mm or 10.75 mm. Similar variance would be present for the plastic housing height, the insertion depth, etc.
The mechanical drawing indicates the female header body height is 8.5mm with 6.5mm insertion depth, which would make the board-to-board (top surface to top surface) distance 12.5mm, very close to my measured 12.7mm (perhaps a measurement error, perhaps manufacturing variation, who knows?). Subtract the 1/16 inch board thickness (probably more than 1.6mm due to plating/soldermask/silkscreen) and you get a spacing of 2 + 10.5 - 1.6mm = 10.9mm, pretty close to my measured 11.1mm.
So for fully-seated 10.5mm headers, you would not have enough clearance for a 12.7mm high component. BUT... the geometry of the contacts within the female socket suggests that you would get full contact with a shallower insertion depth. The drawing does not show measurements, but the drawing seems to show that the contact point is much closer to the top opening than the bottom of the socket, so you might still get full contact with only a 3 or 4 mm insertion depth. This would give a board spacing up to 3mm larger (or thereabouts), which would give a spacing up to 14mm between boards, which should be high enough. In this case, you might want some kind of mechanical spacers between the boards to hold them at the right distance, because the mechanical connection from just the connectors would be weaker.
In short, If you are comfortable with only 1/2 to 2/3rds insertion depth, and using spacers between the boards for stability (not required of course), then 10.5mm length tails might be good enough.
For my M44D40+ module that is in the works, I am looking into the Samtec SSQ series of extended tail headers for this same purpose. In particular, I am looking at 8, 10, and 20 pin connectors. (SSQ-108-03-L-S, SSQ-108-03-L-S, and SSQ-108-03-L-S respectively) These have 10.5mm tail lengths and are equivalent to the 4UCON 18688 (at Sparkfun as Item 9279) The Samtec parts have a lower contact resistance (10mOhm vs 20 mOhm) and higher current rating. Plus, I just prefer Liquid Crystal Polymer over the Polyester material. The Samtec parts are more expensive ($1.52 for the 20 pin, 0.60 for the 8 pin), but worth it in my opinion.
PC104 uses a 0.6" spacer in between boards, which means a 12.7mm D connnector or PS2 connector still has 0.1" above it for soldered through hole legs on the board above (or SMT on the underside of the board above)
Samtec ESQ-120-14-g-d is a 20 x 2 connector specifically designed for PC104. It has 12.19mm (0.48") tail. There is a similar ESQ-132-14-G-D for 32x2
The tallest components being discussed are "about" 12.7mm high (RCA Audio jacks), which is 0.5". Happily, "standard" stand-offs come in 0.5" lengths as well, so I will consider using a 0.5" stand-off (12.7 mm) plus a washer/lockwasher, which will add about 0.5mm to 1.0 mm to the inter-board distance. For now, I will ignore the variance in lengths for the headers (+- 0.25mm worst case for each measurement, or about +-0.5mm total worst case).
So, the board-top-surface to board-top-surface distaince is standoff-size + washer-thickness + board-thickness == 12.5mm + 0.5mm + 1.6mm == 14.6mm.
The header body is 8.5mm and the tail is 10.5mm. So, for a 14.6mm distance, we will get an insertion depth of (8.5mm + 10.5mm) - 14.6mm == 4.4mm (give-or-take 0.5mm). That should be enough for good electrical contact -- it gives a wiping distance on the pin of about 2.0mm to 2.4 mm (depending on the precise geometry of the contacts in the female portion of the header -- and testing would be a good idea as well, which is now on my small project list...)
This should be enough for an RCA connector, with a few layers of electrical tape on top
However, it may be possible to reorder the board stack to avoid some of those component alignment problems. So I think that 10.5mm length tails are good enough.
I like the Samtec headers. It's hard to understand their part numbers though.
The PC104 standard is pretty good, but I always thought the header placements were a little strange.
I'm hoping to avoid using stand-offs, but it's fine to use them for mechanical stability.