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Pogo pins and 2x hat standard [Solved]

Posted: Fri Feb 09, 2018 2:18 pm
by bullen
Hi, what is the standard diameter for the GPIO holes? Is there a standard? Edit: 1mm apparently!

Finally we are getting pogo pins for hats:

https://shop.pimoroni.com/collections/n ... -pogo-pins (edit: these are not ideal, 0.9mm foot makes them wobble)

But these are too long... 4mm is the right distance for a compact design!

The standard should be I2C, SPI0 for front (screen/buttons) and SPI1 for back hats (radio/sensors/battery etc.), 4mm clearance and no soldered header so we can have 2x hats per rpi zero (one above and one under)...

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Re: Pogo pins and 2x hat standard

Posted: Sat Feb 10, 2018 1:55 pm
by bullen
https://www.aliexpress.com/item/100pcs- ... 16758.html

I ordered the PGTH450, we'll see... if they work it will be interesting to unsolder the headers! :S

Re: Pogo pins and 2x hat standard

Posted: Tue Mar 06, 2018 12:07 pm
by bullen
Ok, these fit! Argh, no they don't work... since the top spring pin is same diameter as the bottom pin, it needs to be bigger!

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Also the length came back wrong, you need to ignore the instructions and order as if PGTHXXX where XXX = C not A.

So for me that means PGTH350 for 4mm spacers between the pi and the HAT.

But it might have been a one time error, I have ordered more in different lengths and will post back when I receive them to inform if it's reproducible or not.

Edit: it was human error but the foot is smaller when the pin length is shorter so this also makes it wrong.

BTW new logo, hex spacers and bolts:

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https://www.ebay.com/itm/M2-5-brass-sta ... 2665666825
https://www.ebay.com/itm/M1-6-M2-5-M2-6 ... 3045875509

Re: Pogo pins and 2x hat standard

Posted: Tue Mar 06, 2018 4:37 pm
by davidcoton
bullen wrote:
Fri Feb 09, 2018 2:18 pm
The standard should be I2C, SPI0 for front and SPI1 for back hats, 4mm clearance and no soldered header so we can have 2x hats per rpi zero (one above and one under)...
Edit: one could make the habit to use I2C for input/output hats (screen/buttons) and SPI for headless hats (radio/sensors/etc.).
The problem is that the Hat standard (pHat on Pi0) requires that only one Hat is connected, because they use an on-board ROM for auto-setup and the wiring/coding does not allow two Hats to co-exist.
There are many add-on boards that can be stacked, however, they should not be called Hats because they do not conform to the Hat specification.

Re: Pogo pins and 2x hat standard

Posted: Tue Mar 06, 2018 4:45 pm
by bullen
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Re: Pogo pins and 2x hat standard

Posted: Thu Mar 08, 2018 2:55 pm
by bullen
Ok the second order of pogo pins came back even more wrong, be careful in ordering these.

This is the standard for Raspberry Pi and should probably exist in more lengths than 8mm.

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I'm going to give this a pause now and buy a better soldering iron, time usually solves all problems.

Edit: I think this is the optimal 4.00mm spacing Zero HAT solderless pogo pin:

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Re: Pogo pins and 2x hat standard

Posted: Fri Apr 13, 2018 6:25 pm
by bullen
Custom pins from Hong Kong arrived today.

8x pins bend the PCB slightly, so you probably can't use more than 20x at the same time.

But other than that, these are perfect!

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Found 1mm bolts and nuts to clamp the PCBs in the middle if you need more pins:

https://model-motorcars.myshopify.com/c ... ware/bolts
https://model-motorcars.myshopify.com/c ... dware/nuts

Or if you wanna go cheap just twist them together with some metal thread!

Edit: did a 30-pin just to try, it bends a bit but may work...

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It has the 10 in the second row at the far ends so mileage may vary...

of course the problem then becomes cost; mo pins, mo problems!

Re: Pogo pins and 2x hat standard

Posted: Sun Apr 15, 2018 12:01 pm
by bullen
Now you can buy 1020 of these for 11.5015.50$ (expensive I know, but only volume, as in orders, can bring the price down; classic catch 22):

10x pogo pins https://www.aliexpress.com/store/produc ... 87525.html

To complete the build you need some hex spacers and bolts:

spacers M2.5x4mm https://www.ebay.com/itm/M2-5-brass-sta ... 2665666825
bolts M2.5x3mm https://www.ebay.com/itm/M1-6-M2-5-M2-6 ... 3045875509

Re: Pogo pins and 2x hat standard [Solved]

Posted: Thu Apr 19, 2018 11:29 am
by bullen
Ok, last post, a $9.50 kit with 10x pins and everything else you need for 1x HAT:

https://www.aliexpress.com/store/produc ... 55268.html

I haven't bought this so I don't know how well each component works, but to the looks of it this should be a good buy if you want a compact Zero + HAT combo!

At least much better than the Pimoroni deal.

Disclaimer: I'm not getting anything for this, just did the legwork (specification) and really enjoy a compact standard for the GPIO.

Update 01/06: There seems to be problems with connectivity sometimes (same is happening with Pimoroni's pogo pins) due to the foot not being fast tapered, a workaround is to solder a tiny amount in the crease (I used my x-acto knife to cut a thin slice of solder wire):

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