How to Socket a Microcontroller for Repeated Use

Microcontrollers are great, but the cost of buying new ones for every project can easily burn a hole in your pocket. I like to build custom mechanical keyboards as a hobby, but the microcontrollers are $25 a pop - and I need two per project! That means if I can reuse them, I can save $50 every time I build a new keyboard.

So today I'm going to show you how I socket them for easy reuse.

Materials:

1. Microcontroller (I'm using nice!nano v2's)
2. Hotswap Sip Sockets (2 lines of 12)
3. 24x Hotswap Pins

Note: I bought mine from a keyboard-specific site, but you can also get them for cheap from a local electronics supply store or Amazon. I recommend buying extra sockets and pins.

Tools:

1. 3D Printer
2. Soldering iron
3. Solder
4. Masking tape

Optional:

1. Nail clippers - unconventional, but highly useful
2. High Temperature Tape - Can be used in place of masking tape if you've got it on hand
3. Needle-nose pliers

This jig is used to hold the sockets in place, which will in turn hold the pins and microcontroller. This model is designed for nice!nano v2's, but will work with similar boards like a Pro Micro. As you can see, the design is pretty simple, so if you're using a microcontroller that doesn't work with it, it would be very simple to CAD and print a new one.

If you don't have your own 3D printer, check local libraries or universities, as many will have very cheap 3D printing services.

Place the sockets in the jig, and a small strip of tape over the sockets. This will protect the sockets from the heat of the soldering iron and any potential molten solder from dripping down into the holes.

You can then push the pins through the masking tape into the sockets. I like to do this with needle-nose pliers, but you can do it by hand if you're careful. Consider making the holes with something like the lead of a mechanical pencil, then use the flat of a fingernail to push the pins into the sockets.

Now, place the microcontroller onto the pins, ensuring correct alignment. Nice!nano's have 13 pins per side, but I'm only socketing 12, because I don't need the top 2 pins for my keyboard projects. Triple check this, as it's easier to avoid mistakes here than fix them later.

Also note that I place my microcontroller face down on the pins. I like to do this for aesthetics, but it also helps protect the components on the front of the board.

Solder the pins to the microcontroller. This is pretty straightforward if you've done any soldering before. I'm no professional at this, but thankfully it doesn't have to be pristine to work. Just be careful not to accidentally connect two pins together with solder and you'll be fine.

If you've never soldered before, this is an easy place to start. Touch the heated soldering iron to both the pin and contact pad on the microcontroller, then push in solder until you have a solid connection.

Your results should look something like this.

This part is trickier than it should be - especially if you do it by hand. Since the parts are small, it's difficult to get enough of a grip on both the sockets and microcontroller to pull them apart. You've tried to pull flat LEGO pieces apart before, right? That's why I recommend doing it with nail clippers. They're something you probably have lying around, and they can wedge precisely between the socket and microcontroller without too much trouble.

Alternate between each side, rocking the sockets back and forth, gradually creating a gap and loosening the connection. Just be careful not to actually clip anything, and you should be able to pull the sockets off. Once that's done, you can remove the tape too.

All done! Repeat as necessary. To use, you can superglue the sockets into 3D printed cases, then solder wires to the sockets instead of the microcontroller. Alternatively, you can solder the sockets to an appropriate PCB, which is common with keyboard projects. Then, insert your newly modified microcontroller into the sockets.

This is a great way to save some cash if you work with microcontrollers a lot. It's also helpful for troubleshooting - if you're having trouble, you can easily replace the microcontroller to check if there's a hardware issue.

Happy socketing!