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Where to get .NET Gadgeteer and Netduino GO compatible 10 pin IDC sockets, and how to solder them

Pete Brown - 16 April 2012

When creating modules for the .NET Gadgeteer or Netduino GO, one of the harder parts to source is the 10 pin IDC socket. This is the tiny 1.27mm pin pitch socket you see on the boards.


Manufacturers will get those by the reel in most cases, directly from China. There are several places the average hobbyist can get them from:

All of these sockets are black. The Netduino blue sockets were a custom run by them, and so are not available to us mere mortals :)

Sockets may come in tape, tube, or loose. In a section of cut tape, it looks like this (purchased from community member Valentin):


Samtec tends to ship in tubes, and most sellers selling individual sockets will ship them in bags or loose. It looks like Digikey ships in tubes as well. It takes a fair bit of effort to unzip these and sell them individually, so expect to pay quite a bit more for small quantities.

A comparison of socket implementations

Although they are completely compatible for our purposes, there are some physical differences between the Samtec sockets and the other widely available sockets. The Samtec parts are more expensive, but for hand-soldering, they're friendlier. Why? Because they have a slight undercut or bottom bevel which makes it easier to get a soldering iron in to heat the pad and pin.

In the pictures below, the generic part is on the left, the Samtec part on the right.


Look! A lens flare! I could edit the next Star Trek now

You can clearly see the undercut on the Samtec part on the right. You can also see that the sides of the part extend down further than the body, enabling it to sit on the plastic and not just on the pin headers. This second feature is nice, but probably overkill for most modules. IOW, it's quality, but I'm not sure it's worth the price premium. The extra bump/key on the outside is helpful for positioning during assembly, but doesn't serve any mechanical purpose on an assembled Gadgeteer or Netduino GO board. All you need is the notch. Note that every commercial module and main board I've bought all use the more generic chinese parts.

The undercut is helpful, though. Just look at how much more of the pin it exposes to your iron.

So, if you are new to soldering, I recommend using the more expensive Samtec part. If you have a reasonable amount of soldering experience and/or can make the pad a little longer than the stock footprint (see next section), you can get the inexpensive sockets.

Techniques for designing and soldering the connector

For your own modules, I recommend making the size of the pads a bit longer than the specifications. This will take up a tiny bit more room on the board, but make it easier for you to get your iron. Below are the two profiles: default on left, my current one on the right. Note that I intend to adjust the hand-solder one a bit to make the pads longer so they come into the center a bit better. As they are right now, you can't get a fillet on the heel of the pins. That's hard to do anyway, but I want as strong a connection as possible.


When hand-soldering, first apply flux to all the pads. You may also want to apply flux to the pin bases on the socket -- it certainly won't hurt, especially if the pins look a little dirty/oxidized.


Step 1: Tin one pad

I recommend then tinning one pad in the corner with a little solder. You don't want a giant blob here. As long as you get the whole pad tinned, less is better.


Step 2: Install the socket

Then, holding the socket in place with your fingers (by the plastic), melt the solder to wet the one pin and hold the socket in place while applying downward pressure to make sure it seats flat. I used to tin all the pads, but I've found it much easier to tin a single pad. You're not looking to make an electrically sound connection here, just something to hold the socket flat.

If you need to adjust the position of the socket, make sure you completely melt the solder on that pad. If it's only half-melted, the leverage you have with the socket will rip up the pad. I did this once. Not good!

Look at the board edge-on and make sure the connector is seated flat and the pin is touching the pad, not suspended above it on a blob of solder.


Step 3: Secure the socket at the opposite corner

Then, once the socket is in the correct position and all pins are centered on the pads (or close) and sitting completely flat, solder the opposite pin to firmly hold the connector in place. Don't apply too much pressure, or you'll move the socket and possibly tear up the first pad you soldered. Once you get past this part, all the tricky parts are done.


Step 4: Solder the remaining pins (including the first one)

Then, solder each pin, including the first one you tinned. The pins are a bit chunky for drag soldering, so you really need to do one pin at a time.

I do this by using a relatively fine chisel tip on my iron. I touch the side of the pin along with the pad at the same time and then add enough solder to ensure a strong connection. Make sure you heat both the pad and the pin. You can see here how the larger pads really help with hand-soldering. If you have a larger tip, you will end up heating more than one pin at a time, but it will be more difficult to get the pads. In that case, apply a bit of downward pressure to try and transfer heat between the pin and the pad.


The sockets are pretty robust, but try not to touch the plastic with the iron. It's normal for flux to smoke a little, but you don't want that extra special kind of smoke that comes from burning plastic.

Step 5: Inspect and Check

I tend to use a little too much solder on these joints. You can use a bit less than what I have here. Getting a nice fillet with these sockets is hard, though. Even the commercial modules and main boards tend to have a bit too much solder here, so I wouldn't worry too much about it as long as the connection is sound and the solder isn't adhering to the plastic.



That's it! Visually inspect the board from a number of angles to make sure everything is soldered correctly and that there are no bridges. Using a multimeter, you can check each pin against some other connected part of the board to ensure continuity.

posted by Pete Brown on Monday, April 16, 2012
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8 comments for “Where to get .NET Gadgeteer and Netduino GO compatible 10 pin IDC sockets, and how to solder them”

  1. Petesays:

    Thanks. The Samtec part is what's actually specified in the Gadgeteer document. The problem is they're so expensive (almost $2.00 each even in quantity). Get a free set of 10 samples if you can.

  2. Petesays:

    Good point. That will help make up for the lack of flux during a reflow.


    I used to tin all the pins, but what a pain in the butt. You can't get anything level that way. I found tinning just the one works much better. That's probably pretty obvious to some folks, but it took me a few tries to realize it :)


    I totally agree. Thanks.


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