The Big Dill Extended (BDE)

The BDE started out as a joke on a Discord server but after some tinkering and designing, we realized we had a surprisingly functional board on our hands. And since this started out as a ‘for fun’ project, we managed to pack quite a few features into this compact package.

Product Page

The Big Dill Extended (BDE) is a pretty simple do-it-yourself kit that can be used to teach some of the more basic principles of keyboards and can also an opportunity for some low-stakes solder practice. If you have any problems during your build, feel free to stop in to the MechWild Discord Server and ask for assistance. I hope you have as much fun building it as we did designing it!

Required Tools and Components

These tools and components are required to complete the project and are not included in the kit. The linked names of the components will generally link to a place where you can buy them.

These tools are not necessary to complete the build, but might make the process a little easier for you or help you correct mistakes if you make them.

Included Components

These components are included in your kit.

Note: You will likely have extras of some components. This is normal and is to account for small mistakes.


1x PCB



1x Switch Plate


1x Bottom Plate


41x 1N4148 Diodes

1N4148 Diodes


41x Kailh Hotswap Sockets

Kailh Hotswap Sockets


1x ATmega32U4 ProMicro with headers

ATmega32U4 ProMicro with headers


1x 6x6mm Reset Button

6x6mm Reset Button


8x M2 12mm Standoffs

8x M2 12mm Standoffs


16x M2x6 Screws

M2x6 Screws


8x Rubber Feet

Rubber Feet


Step 0: Choose Numpad Orientation

Alright. This is it. Game time. Time for you to make the most difficult decision you have ever had to make. 

This decision could very well change the rest of your life.

Get ready.

Do we put the numpad on the right…..or the left?

BDEs with both configuration options

That wasn’t too bad, was it? Well, even if it was, good news is that was one of the hardest steps in this entire guide.
Remembered your choice. We will be using it the whole time. For the sake of this guide, I will be showing a build with the numpad on the right. For the rest of this guide, I will be referring to the different builds as “righty” and “lefty”.

Step 1: Check Components and Flash Pro Micro

This step is simple, but will make sure we are starting things off on the right foot. Two main things to do here: Count everything, and plug in the pro micro to ensure that it is working correctly. If you are not familiar with how to test out or flash your pro micro, first give this guide a read. If you plug in your pro micro and the red led comes on, that is the first good sign. I highly recommend that you attempt to flash the BDE firmware with your chosen orientation at this point. You really REALLY don’t want to solder the pro micro into place and then realize it doesn’t work.

  • Ensure that your part count matches the list of included components
  • Plug in your pro micro and verify that it is being powered on
  • Flash it with firmware that you built using the following command:
    make mechwild/bde/:default                 
    For example, to flash the righty version for the build I am doing as part of this guide, I would build with the following command:
                                                                    make mechwild/bde/righty:default
    And then flash it like I normally would (from command line or QMK Toolbox, as described in the newbies guide linked above.)


Looks like success!


NOTE: While there is currently an option for a keymap with VIA support, it is not currently supported by the VIA software. You can flash the VIA build of the firmware to your board and when VIA is updated and the BDE is approved for inclusion, it will show up and allow you to customize it that way.

Step 2: 1N4148 Diodes

Now to start soldering. First, make sure we are working with the correct side of the board.

For me, since I am build a righty version, I will look for this text at the top center of the PCB:

The side that it says to solder is going to be the side you put all the components on. This side for righty or the other side for lefty.

Now we are going to prepare the diodes to be soldered. You can either bend then against the edge of a table (or some other straight edge) or do this with a lead bending tool like this (the diodes fit perfectly in the keyhole at the end of this larger sized one, so I use that):

Bending the leads nice and uniformly is optional but people on the internet will probably make fun of you if you don’t do it very neatly. I will be bending all of the leads with this tool since you will have to look at them as we go.





Make sure to insert your diodes to match the symbol underneath. The black line needs to be on the same side as the line in the symbol.

Once the diode is in place, what I like to do is hold it in place, and bend the leads outward a little bit to keep it from falling out. This allows me to go and put a handful of diodes in, then solder then one after another.

Now you are going to solder your diode into place. Going into detail on how to solder is a little beyond the scope of this guide, but here is a link to SparkFun’s guide, an excellent resource for hobbyists.


After you have soldered the diode into place, we are going to trim the leads so that they sit as low as possible.

Now that we’ve done one together, go ahead and do the same for all of them. The direction of the line is not the same for all rows (though it is the same for the entire row) so please make sure to pay attention to that.

Diodes done!

Step 3: Kailh Hotswap Sockets

Now for our next component. The hotswap sockets. These Kailh hotswap sockets are surface mount, which is a different type of way that the component gets attached to the board. That means you’ll have to solder slightly differently. We only want to solder one side of each socket for now, then we will go back and hit the other side afterwards.

For a quick summary, you will put the socket into place on the board, place the tip of the soldering iron into the little area on the metal part on the back of the socket, and then feed some solder underneath. When the solder has flowed up and onto the outside metal leaf on the socket (where the iron is), you need to hold the socket in place, and pull your soldering iron away. In this example picture, I am using tweezers to hold it into place:

Sometimes, if you aren’t very careful, the socket might come up a little bit. Don’t worry, this is pretty easy to fix by reheating the solder and pushing it down. This is why we are only doing one side at a time, since trying to reheat both sides at once is a little more tricky.



Good alignment on the left, one that needs to be fixed on the right.

After you have each socket seated properly, make sure to go back and solder the other side to complete the connection.

Lookin’ good so far!

Step 4: Pro Micro and Reset Button

Next step we are going to give our keyboard a way to talk to the computer. Let’s start off with this step by putting the button on to the board. In the top right of the board on the same side as all the other components, you are going to take your reset button and put it in the holes near the symbol labeled “SW42”, then you will flip the board over, bend the bits of the pins that are coming through the pcb down as flat as you can, and solder it into place.

After that, we need to put the pro micro on here. The pro micro is always attached on the right side of the board on the same side that you soldered the rest of the components on. To do that, we will be putting headers on the board and soldering them to the pro micro and also soldering them to the PCB itself. Since the header pins pass through the board, in order to do this step we need to prop up the board a little bit, in my example picture here, I am using the lead bender I used early, but you can realistically use anything nearby as long as it isn’t moving around a lot. 


Now after both header pins are seated flat against the board with the short nubs facing you, place the pro micro onto the pins like this:

Next we are going to go ahead and solder the first and last pins on each half of the board so that all 4 corners are soldered into place while making sure that the pro micro is seated snugly against the spacers on the pins.

Now it is secured to the pins enough for us to flip the PCB over and solder the other side of the pins to the board. You no longer want to prop up the PCB and instead want to let the PCB rest on the pro micro itself. Be gentle and do not put a lot of weight on it, but we want to let gravity help us out here and use the weight of the PCB keep the pro micro seated nicely in place while we solder. Once you are sure it is sitting as snug against the PCB as you can, solder the corners into place to make sure it doesn’t move, then go ahead and solder all the pins on this side.

After that, you can flip the board back over and solder the rest of the pins on the pro micro as well.

After all the pins are soldered, you now need to flip the board back over so the pro micro is on the bottom, and clip all the long pins left sticking out so they don’t interfere with the switches.

Perfect! We are all done soldering and mostly done with the build! Time to check our work.

Step 5: Test

Not a whole lot to do here. Plug it in and use your favorite key tester to check to make sure all the sockets are working by touching both metal solder points with a pair of tweezers at the same time. It is a lot easier to fix the troubles now before putting everything together.

Step 6: Stabilizer

This step is only necessary if you are using a PCB mount stabilizer. If you are using platemount, you can add it after assembling the case. I will be using a PCB mount, so I’ll show that here.

Step 7: Assemble Case

The way that I have found this to be easiest for me is to screw one end of each of the standoffs into each of the holes on the bottom case portion, then putting the PCB on top and letting it rest on the bottom of the case, while you screw the screws through the holes on the switch plate into the other ends of the standoffs. When this is done correctly, the PCB won’t be connected to anything and will be able to move back and forth a little bit and will just be guided where it is supposed to be by the standoffs that are passing through it.



The final thing we need to do with the case is put the little rubber feet on the bottom. For my build, I am only using 4 of the 8 that come with the kit, one in each corner, but you can also put one near each of the screws on the bottom of the case for the best grip.

Step 8: Insert Switches

No instructions really needed here, but go ahead and throw your switches of choice into it. I like to start with the corners in order to hold the PCB into place for the rest of the switches, since the PCB can move around. To hold the PCB in place for the first couple switches, use your finger on the side of the case like this picture.

Then do the corners.

Next put the rest of the switches in.

Alrighty. All done and your board should be sturdy feeling now with the PCB unable to move since all the switches are seated into it.

Step 9: Test Again

You guessed it, time to do the final testing on the keyboard switch tester on your computer to make sure every switch is working as expected.

You know what to do.

Step 10: Keycaps

Now grab your favorite keycaps…

No. Not those.

Your favorite ones.

No, your actual favorite ones that you won’t let other people type on. 

Yes. Good. Those. Grab those and put them on here.

Step 11: Customize and Enjoy!

Now you have a fully functional and feature packed keyboard to go off and type out your deepest thoughts with. Go ahead and check in to the MechWild Discord server and chat with us using it. Typing on the BDE takes a day or two to really get the hang of, but make sure not to give up as it is oddly satisfying when you get the hang of it. If you have any questions about how to do some things (such as use modifiers on a 30% keyboard) drop into the Discord and ask while trying it out.