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Shield assembly - installing the stacky headers

Save yourself some pain:

Don't even turn on your soldering iron until you're absolutely confident you know where the headers are supposed to go.

There are two sets of holes along the sides of the boards. Aside from position, they're identical in every way. That's an open invitation for Murphy's Law to smite the unwary. Trying to unsolder header is a pain in the neck, and stacky header is doubly so.

The headers go into the outside row of holes, closest to the edge of the shield. They're outlined in green to the right. The hardwire holes are the inside row, closest to the jacks. They're outlined in red.

Use the Arduino as an alignment jig

Lay the board on your Arduino and press the stacky headers through the holes. Not only does this ensure that you're putting the headers in the right place, it guarantees that the pins will line up with the Arduino in the future.

Believe it or not, that matters. For ease of insertion, you want the ends of all the pins to line up with the Arduino's headers to within about 10 thousandths of an inch.. roughly the thickness of the pin itself. That's not the kind of thing you can freehand, especially considering the slop in the holes, the room for angular error, and the length of the stacky header pins.

Trust me. This works better.

One more time:

This is how it should look. Headers to the outside, hardwire holes to the inside.

And now we're ready

Flip the assembly over, and press the shield down so it's flush to the headers.

Ladies and gentlemen, start your irons... it's time to solder.

Tack the headers in place

You don't have to solder all the pins like this. You just need to make a quick connection at the first and last pins of each header.

The joints don't even need to be very good. You only need enough to hold the header in place when you pull it out of the Arduino and solder the rest of the pins on the workbench.

Tacked

Here's a shot of the tack joints I made for the sample board. As you can see in the full-sized photo, they're nothing great. The ones to the upper right don't even wrap all the way around the pin. That's okay though. They were good enough to last five minutes.

When you get the board onto the bench, solder the center pins first, then go back and redo the end pins. That way you always have a solid mechanical connection holding the headers in place.

(Note, BTW, how nicely the ends of the pins line up)

And done

When the header pins are soldered to your satisfaction, you're ready to move on to the next step (whatever that is).