arduino (pro) micro macro keyboard V3

A macro keyboard using Arduino (pro) micro with selectable macro profiles and an OLED screen to indicate the profile selected. It uses a PISO shift register to determine what key is pressed instead of a diodes and resistors. It uses Cherry MX switches or clones of it to really capture that keyboard feel. It can do a lot more than simulate key presses though, it can replicate a mouse, launch programmes and much more! I've left an easter egg in profile 5 :).

I built this macro keyboard because I was spending way too much time with repetitive keystrokes, I also needed a quick way to trigger media functions without needing to switch windows. The ones in the market were way too expensive and finally, after looking up many designs of people who've built their own macro keyboards and finding only a few with a display, none of them could meet my criteria, thus I had to build my own.

I decided to implement an OLED display that's compact and instead of a diode-resistor configuration I've decided to go with a shift register instead, simply because the complexity of the PCB is brought way down with fewer components to fail and its a lot easier to replace a socketed dip-16 IC than it is to desolder a diode and the number of GPIO pins I save using a shift register allows for future expansion.

Apart from the code and required libraries, the PCB gerber files, 3D CAD files for the housing, parts list and snapshots of the different skews are included as well. Do note that the Arduino (pro) micro that is compatible with the current PCB and 3D CAD is 17.9mm in width and it has either USB type C or micro-usb connector, the mini-USB version will not fit!

Features:

1. OLED display
2. Profile selector button
3. Reset button
4. Rotary encoder
5. By default there are 18 possible macro combinations per profile but it can go up to 22 for normal humans and 254 for geniuses who can remember that many combinations, but do mind the amount of available memory

Blown up view of components:

Code and usage:

1. Ensure you have the Arduino IDE installed
2. Download and unzip 'required libraries.zip' and 'arduino_micro_shift_register_piso_rot_enc_psbtn_OLED_V3.zip' files.
3. Go to the 'libraries' folder in your arduino installation and paste the 2 subfolders inside the 'required libraries' folder into the 'libraries' folder in your arduino installation.
4. Then open the arduino_micro_shift_register_piso_rot_enc_psbtn_OLED_V3.ino file.

How to modify the code to suit you is explained in this youtube video: https://www.youtube.com/watch?v=DriOpHgIRV4

Dont hesitate to drop me a message if you need additional clarification, I'll get back to you as soon as I am able to.

PCB:

Top:

Bottom:

The current PCB uses cherry MX or similar key switches as buttons, feel free to use any switch you like! The 10K resistors on the side can either be in the SMD 2010 from factor or THT. If you're using the SMD 2010 form factor resistor, you have the option of soldering them either on the top or bottom of the PCB depending on which version of the CAD housing you want to print. If you want to see how both skews look, scroll down to the next section or open 'comparison.png' in the snapshot folder.

I used JLCPCB.com to make the PCB, they're pretty fast and reliable, hence the "JLCJLCJLCJLC" on the bottom side. I put that there because I wanted the ugly order number to be hidden from view, if you do use JLCPCB.com to make the PCB, upload the entire "PCB_Gerber.zip" file and make sure under "Remove Order Number" you select 'Specify a location', its at no extra cost.

PCB components: (all links available in 'parts list pdf.pdf' file)

1. 1x Arduino (pro) Micro
2. 1x Rotary encoder with round PCB
3. 9x Cherry MX clone keyboard switches
4. 9x Cherry MX compatible keycaps
5. 1x 128x32 OLED
6. 1x 12mm tactile push button switch with switch cap
7. 1x DIP-16 74HC165 PISO shift register
8. 8x SMD-2010 or THT 10K resistors
9. 2x 4 pin female PCB header pins
10. Optional but highly recommended 1x Rotary encoder knob
11. Optional 1x DIP-16 socket or 2x DIP-8 sockets

IMPORTANT NOTE: YOU NEED TO SOLDER THE COMPONENTS IN A CERTAIN ORDER!

Soldering order as follows:

1. Solder the SMD or THT resistors

2. Solder the 12mm tactile switch to the top of the PCB

3. Solder the DIP-16 socket or 74HC165 directly to the PCB with the identifying indented notch on Pin 1 pointing towards the left where the "O" on the PCB is

   

4. Solder the Arduino (pro) Micro to the bottom of the PCB

5. Optional snip off the Micro's pins that extend from the top of the PCB

6. Solder the 2x 4pin female PCB header pins for the OLED

7. Solder all the Cherry MX or clone key switches

8. From the bottom of the Rotary encoder, remove the extra black plastic holding the male header pins and attach a piece of tape to the bottom of the rotary encoder covering the resistors etc.. This is done to stabilise the rotary encoder. I used the tip of a wire cutter to remove it.

   One tip to ensure the encoder is level, is to dab a little soder on 1 pin and then holding the soldering iron to the pin with the soder on it and straightning the encoder. Its a little tricky but take your time

9. Solder the rotary encoder to the top of the PCB

10. Finally, remove the extra black plastic holding the male header pins of the OLED display and snip about 2mm off the bottom and put some double sided tape on the bottom right side of the OLED. Place the OLED display in the 4 pin female PCB header pins to test the height and ensure its sitting level and it's right side rests on the other 4 pin female PCB header.

Congratulations, you're done! If you have a multimeter, I recommend that after every step of soldering, you go into continuity test mode and check that your connections are solid and you haven't shorted or connected any pins together or you'll be in for a bad time. I also recommend ensuring all your cherry MX or clone key switches work before soldering them on to the PCB.

If you've never done a continuity test before, you hold one probe to one pad or pin and then the other to the part it's supposed to be connected to, either a PCB trace or a neighbouring pin. If the multimeter buzzes, a connection is made, whether or not thats a good or bad thing will depend on whether a connection is supposed to be or not to be made.

3D Printable CAD housing

The main components of the housing are the PCB cover and the housing base. You can choose to laser cut the PCB cover if you want. Raw CAD files are in: 3D CAD files folder > raw step files. STL files are in: 3D CAD files folder > stl files.

There are 2 versions of the PCB cover, one version is when the SMD or THT resistors are soldered to the top of the PCB, the other is when the SMD (only) resistors are soldered to the bottom of the PCB, snapshots of what both versions will look like are in the 'snapshots' folder. I decided to solder my SMD resistors to the top of the PCB as I quite like the look of it.

Mounting options

You have plenty of options for mounting the PCB to the housing base since I've made the holes slightly smaller which gives you the option to use self-tap screws or machine screws with nuts or machine screws with tapped holes; you can literally use whatever you have at hand but keep in mind that the screws I intended to use are M3 so make sure you have the correct size.

I've opted to drill 3mm holes in the housing base and PCB cover, then used M3x20mm screws with plastic M3 spacers to fasten the screw from the bottom of the base to the top of the PCB cover. Finally, I've added anti-slip pads to the bottom of the housing base to prevent it from slipping.

Optional- Cover piece for extra style points

The additional rotary encoder/reset button/OLED cover piece is nice but not necessary. If you do decide to 3D print or laser cut it, you will need to:

1. Ideally tap M3 threads into the 3 holes in the PCB cover or less ideally heat up an M3 screw and screw into the cover piece to create the thread

2. Screw 3x M3x6mm brass spacers into the holes

3. optional drill 4mm holes into the cover piece if the screws dont go in right

Optional Optional- Transparent acrylic OLED cover for style points over 9000

This transparent acrylic cover will cover the OLED, I used my cutting table to make it but you can use a laser cutter to cut it out as well. The thickness of the clear acrylic should be from 1 to 3mm, the thinner it is the better. If you do decide to include this, replace the bottom 2 M3x6mm screws holding the cover piece to the PCB cover and replace it with 2x M3x10mm screws

Special thanks to:

NicoHood for developing the HID library and Henning Karlsen of Rinky-Dink Electronics for developing a lightweight OLED library. DroneBot workshop for providing the basic code to run the 74HC165 PISO shift register. Their libraries are included in the ZIP file.