MurphPad Build Guide

MurphPad

The MurphPad is a numpad through hole DIY kit with an OLED and rotary encoder. We developed this numpad kit as we couldn’t find a numpad with enough keys. We found that we were always wanting something more like some extra function keys or a knob so we made our own.

Product Page

The MurphPad is a through hole kit and won’t pose too much of a challenge, even to soldering novices. If you have any problems during your build, feel free to stop in to the MechWild Discord Server and ask for assistance.

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

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

1x PCB

1x Switch Plate

1x Bottom Plate

30x 1N4148 Diodes

1x Pro Micro & header pins

4x 6x6mm Reset Button

7x M2 8mm Standoffs

14x M2x5 Screws

 

4x Rubber Feet

1x Rotary Encoder

1x Encoder Knob

1x I2C OLED

Step 0: Inspect PCBs and Components

Take your kit components , lay them out, and make sure you have everything listed above. Additionally, while we try and make sure to not send any defective PCBs out to you guys, mistakes happen. Make sure you check over your PCB and look for anything out of place. If you solder everything together before noticing a problem with the PCB, we will be less able to help you get a replacement (as it is harder to verify we sent a defective one and you didn’t damage it yourself.)

Step 1: Test, Program, and Solder Pins on Pro Micro

Plug in your Pro Micro and flash it to make sure it works. You absolutely want to make sure the Pro Micro works before soldering it to the board, as removing a defective one can be quite bothersome.

MurphPad Firmware

QMK Toolbox (download the .exe)

If this is your first time flashing a Pro Micro, you will need to download QMK Toolbox as well as the firmware you’ll be flashing (both linked above, how generous). Run the program and allow it to install drivers when prompted. Next, you will Open your firmware file you have just downloaded. Your firmware file name may differ from the one in the following screenshot. Make sure the MCU field reads “atmega32u4” and the ‘Keyboard from qmk.fm’ field is left blank. Also, check the “Auto-Flash” box. Your QMK Toolbox window should look like this:

Now plug in your Pro Micro and locate the RST and GND pins.

 

You are going to form a connection between these two contacts using something like metal tweezers or a paperclip or a loose piece of wire. Very briefly make a connection between these two points and your QMK Toolbox should output a good number of lines. If you’ve successfully followed these steps, your QMK Toolbox window should look like this:

After you have it verified as working, place the short end of the pins into the PCB, and put the Pro Micro onto the long side of the pins with the components facing towards the board. This will leave the flat side facing upwards.

I then solder the four corners and ensure that the pins are perpendicular to the Pro Micro (straight up and down, basically.) After they are lined up, go ahead and solder all the pins, then trim the excess of the pins off as closely to the Pro Micro as you can. Then remove the Pro Micro from the PCB and place it to the side for now.

Step 2: LEDs

THIS STEP INVOLVES SOLDERING COMPONENTS TO THE PCB. FOR THIS ENTIRE KIT, YOU WILL ONLY EVER SOLDER COMPONENTS ON TO THE PCB WITH THE COMPONENTS PLACED ON THE SIDE OF THE PCB WHERE THEY ARE OUTLINED AND LABELED. THIS OFTEN MEANS THAT FOR THROUGH-HOLE COMPONENTS, YOU WILL BE SOLDERING ON THE SIDE WITHOUT ANY LABELS.

Remove the LEDs from the strip packaging and place them to the side.

I then like to arbitrarily pick a direction to have my board and start by soldering the top right pin of all the LED positions that are on the left and right sides. In the second picture below, it is the position circled in red. We are just putting some solder on the pad to prepare for the LED being attached, right now.

Now we will take the LEDs (one at a time) and line it up with the silkscreen. The corner of the LED that has a little triangle portion missing will line up with the corner on the silkscreen that is L-shaped. Line one up with one of the spots you prepared the soldered pad of, slide it towards the solder using your finger or tweezers, touch the tip of your soldering iron to the solder you placed beforehand to reflow it, and then make sure the LED is centered amongst the four pads. At this point it is not securely attached to the board and could still be ripped off if pulled too hard (or damage the LED), but it shouldn’t fall off if you tilt the PCB.

I then like to do that starting corner for all 4 I prepared, then do the bottom right corner second. I use the right side first for this because I solder with my right hand and it is easier to solder that side for me. If you solder with your left hand, you might have more success starting with the left sides.

After you have the right side of all four done, go ahead and flip it 180 degrees, and do the other side of those four LEDs.

When you are done with those four LEDs, rotate the whole board 90 degrees and do the remaining four LEDs the same way.

Step 3: Buttons

Put the four buttons in the positions outlined for them, flip the PCB, and solder them. You can clip the legs if you like, but it is not necessary.

Step 4: Diodes

We now need to bend all the legs for the diodes into 90 degree joints. You can bend them all at once using some kind of straight edge (I use tweezers) or, if you have a ridiculous amount of free time, you can cut them away from the strip, and bend them one at a time. If you bend them all at once, you next need to cut away the tape. You can safely cut some of the legs away without any issues, so don’t worry about losing a small amount of leg length.

Place your diodes into the board. Either do them all at once, or do them in groups. Make sure the black bar on the diode aligns with the solid bar portion on the outline of the diode in the silkscreen. It won’t work if you have it backwards.

Solder all the diodes in and clip the legs short. Same as any other board.

Step 5: Solder Pro Micro to PCB

Put the Pro Micro back into the PCB, flip the PCB, and solder it into place. I start with the 4 corners, make sure it is seated appropriately, then do the rest.

Once you have the pins all soldered, go ahead and trim it as close to the board as you can.

Step 6: OLED

Your strip of header pins might have 5 pins instead of the standard 4 for the OLED. If this is the case, DO NOT PANIC, as we have procedures in place for this exact situation. If your OLED came with a strip of 4 pins, you maybe continue to the next part of this step. If you have a strip of 5 pins, you will need to clip off one of the pins, preferably off the end of the strip. 

Line the pins up perpendicularly with the OLED, solder one of the non-ground pins (AKA not the one labeled as GND) and make sure it is aligned correctly, then solder the rest of the pins into place.

After all four pins are soldered, pull the plastic spacer off the long side of the pins. I find that this is easiest to do by working tweezers under them and then prying it upwards.

Place the OLED into the PCB and make sure that it is sitting parallel to the main PCB and Pro Micro, then solder one of the center two pins to hold it in place. From there, you now need to flip the board over and make sure it is aligned with the cutout on the PCB. Line it up as well as you can, since this is a very visible component on this kit. With only one pin soldered, you can bend the pin from right to left pretty easily to align it.

After the OLED is aligned, solder the rest of the pins, and clip them short.

Also make sure to clip the pins on the top side. I recommend clipping them one at a time and not trying to rush this as you may accidentally damage the screen itself if you are not cautious with the snips. I am totally not speaking from experience.

Step 7: Encoder

Line the pins up from the encoder, put it in on the top side (same side as the OLED) and then flip it and solder it into place. The pins might need to be lined up to make sure they fit correctly, as sometimes they get bent out of shape during shipping.

Step 8: Plug In and Test

If you didn’t flash the Pro Micro earlier, do that now. When you plug it in, the OLED should come on, and the SMD LEDs should all light up red. Eight red LEDs and a working OLED are the true marks of a successful build. If those are showing up correctly, go ahead and test out the encoder by turning it and clicking it in to see if you can control the volume and mute on your computer.

Step 9: Install Stabs and Switches

As with all other keyboard builds, your next step will be installing stabilizers onto the PCB. 

Once your stabilizers are in the PCB, you can set it aside for now and insert some switches into the plate. We recommend filling in the corners and installing some switches in the center of the plate.

You can now take this plate+switches assembly and place it on top of the PCB, making sure the switch pins poke through the PCB. From here, you can insert the rest of the switches and be sure to check each switch is fully seated in the plate and both switch pins go through the PCB.

When all your switches are seated in the plate, you can solder them in. I will not be doing this in this guide.

Step 10: Standoffs, Screws

If you have already soldered switches, you will be doing this step through the top plate using the passthrough holes in the plate itself. I recommend thumb screwing the standoff on the bottom case plate, resting the PCB on the standoffs, then putting a screw through the holes in the switch plate and screwing it into the standoff. Do this how you like, it is pretty hard to mess this step up.

Step 11: Customize and Enjoy

I recommend now having a celebratory party with your neighbors and loved ones. Make sure everyone is vaccinated and healthy though. Don’t want any uninvited germs.