Ploopy: Project Ruby – Trackball Mouse

I am in the process of ordering some boards to test. I am hoping it will work right off the bat, but a lot has been added! Read below for more info.

Copied from my readme file

Ploopy v1.01 – Project Ruby – modified by Keys of Kings ~ King Icewind

I’m a daily user and big fan of trackballs, so many thanks to the original creators of Ploopy. This has been a fun project. I’ve dubbed my modification as Project Ruby or also known simply as Ruby.

The Ploopy was originally built in Altium. I’ve rebuilt the board in KiCad and have done some revisions. I’ve stuck with the same component naming as the original. The PCB is similar to the original but has many added features. Please also check out notes in the schematic.

Digikey parts list is also available. Just upload the excel file to an empty cart. Quality capacitors and resistors were chosen. **You will need to buy the PMW3360 sensor and XZTHI56W-1 LED elsewhere.** ***Please read notes about components below BEFORE ordering.***

Revision Log 1 – 1.9.20

-Rebuilt in KiCad: files will be available
-4 layer change: SIGNAL, GND, VCC, SIGNAL
-Add-on Board: connects via a ribbon cable. This board has a breakout shield (16×10) with the intent of adding a Bluetooth module. It also has WS2812B underneath so the full mouse can have underglow. The Adafruit Bluefruit SPI Friend will fit along with others
-Boards are attached as one PCB for ease of ordering from manufacturer
-Lithium-ion Battery charging capability added to Main Board with TI BQ21040. Off switch also added to bottom of board. Fast Charge set to 500mAh
-Main and Add-on board now mount via grounded and non ground screw locations. Can still be used as it was previously
-WS2812B RGB underglow added to Main Board and Add-On Board. Please note that you will not be able to use underglow if you’re powering the board via battery. PD3/TX is used to signal the WS2812Bs, which is often used in conjuction with Bluetooth
-3 buttons on bottom for intended use of turning off/changing RGB underglow, DPI, etc.
-Piezo buzzer added: use for fun sounds like low battery, cable connected, etc. Capacitor optional
-Capacitors and Resistors now 0603 to better accommodate the additional parts

-USB B port replaced with through-hole USB C for ease of hand soldering (hot air) and strength
-VBUS now has a PTC resettable fuse
-USB GND changed to just ferrite

-AP2202K-3.3 replaced with TPS73133DBVR for even less voltage drop, less noise, and more protection features
-AP2204K-1.8 replaced with TPS73118DBVR “” “” “”
-BYPASS capacitor used for TPS73118DBVR for low noise operation

5V (VBUS), 3.3V, 1.8V LED indicators added

-RESET button added for easier flashing with QMK. You may still flash through the headers, although many of these pins are also tied to the Add-on Board/Bluetooth, so it may be best to disconnect the Add-On board if flashing the ATMEGA32u4.
-CS, SCLK, MOSI, MISO, PB7, PDO/SLA, PD1/SDA, PD3/TX, PD5, PC6/PWM, 3V3, 5V, GND are now broken out to a ribbon cable connector which attaches to the Add-on Board for additional mods
-Crystal grounded
-AREF connected to battery to measure voltage. With programming the piezo buzzer can be used to notify low battery

-THE XZTHI56W-1 and comparable spec IR LEDs are hard to find: Footprint was modified to support through hole IR LEDs and 2-SMD/Boomerang (AA4040SF4S-P22). These may require modification of the wheel

-Files available in Autodesk Fusion 360 – I don’t have the original design files, so these are imported STL files
-USB port modified to support USB C
-Case extended to support holding a lithium-ion battery. Internal battery cover also added. A 1000mAh lithium-ion battery will fit.
-Extra screw mounts for PCB
-Bottom Reset and other button access
-Side piece that supports the Main and Vertical board has been modified to support a mounting screw underneath
-PLA markings removed from bottom
-Keys of Kings crown badge added
-Additional case files added: Case modified to support printing with smaller resin SLA/DLP 3D Printers
-Additional case files added: Left handed case added with above changes


-USB C CC lines pulled down with 5.1K resistors: Max current 900mA. Though you shouldn’t exceed 500mA
-LFXTAL055663 (crystal) quantity is low on Digikey: suggested part change to ABMM2-8.000MHZ-D6-T
-TPS73118DBVR and TPS73133DBVR are more expensive but worth the cost in my opinion. If you must save $0.60 replace with TLV70018, TLV0033.
-LED PWR Indicators are optional. The MCU is equipped with a LED, but, lighty lights. Resistors used were 1k and 100 ohm to save on unique parts as they were already used in the project. Please read schematic for more info.

Squire ~ Hand-wiring

Hand-wiring your Squire

What is needed

  • Case + Stand Offs
  • Plate
  • Pro Micro or Teensy 2.0
  • 22-25 x Switches (Cherry, Gateron, Matias, etc.)
  • 22-25 x 1N4148 Diode
  • Key caps
  • Wire – Recommended: 26 gauge Solid Strand
  • Optional: Small Switch to easily reset Pro Micro (included with the Squire)


  • Solder Gun – Recommended: Hakko 888D
  • Solder
  • Wire Stripper – Recommended: Klein Katapult
  • Wire Cutter
  • Safety Glasses & Mask

Getting Started
This guide is specifically about handwiring your Squire. It will, however, also apply to other keyboards.  I suggest reading over the guide before you start. You may also choose to flash your Pro Micro or Teensy before hand.

I won’t be going into specifics in how to solder for this guide. If you’re new to soldering, I do suggest your iron be set to around 330C. Please make sure to wear eye protection and properly place your soldering iron back into its holder. The area you solder in should be well ventilated and if using lead solder please wear a mask.

(L)First Prototype Squire with unusual keys – (M)Prototype Keycaps with 2U keys – 25 1U Layout

1. Layout & Switch Placement
This is your time to decide if you want a standard Numpad (2U size key caps on the 0, +, and Enter keys), or all 1U size key caps.

1. Start by inserting each switch into its designated hole. The switches need to be placed in a particular way. The connections for 1U spacing should all be on the top, with the left being higher than the right. For vertical 2U keycaps (+ and Enter) rotate the switch counter clockwise, so the connections are on the outside of the plate. Please look at the picture to see the correct orientation and location.






Squirt some hot glue between the left/right sides of the switches and plate to help keep them from coming out. Do this from the bottom side of the plate. This is particularly helpful when pulling off keycaps.

2. Diode Direction & Soldering
Next, you will be soldering the diodes to your switches. We need to pay attention to the correct orientation. The black band (cathode, negative) on the diode will always be at the bottom/south, and solder to the left connection of the switch. Please refer to the image below for the correct direction.






1. Start by placing a small amount of solder on the left connection of each switch. You can save time and do it for the right side as well.
2. Trim the terminal below the black band of your diode so there’s only about 0.1″ remaining.
3. Place your diode flat against your switch and in the middle. Make sure the black band is at the bottom. I recommend only doing a row at a time.
4. Melt the solder onto the diode.
5. Trim the terminal connection as close as you can to the solder. You may also choose to trim this terminal before soldering.
6. Repeat steps 1-5 for each switch.

3. Wiring – Columns 
For this step, start by wiring up the right connection of the switch. These connections are connected vertically which make up your columns. The Squire does not have a staggered layout; it is very straightforward on what your columns are. For staggered layouts: choose a side, start from the top, and simply work your way down to determine your columns. Not every column will have the same amount of switches, or be perfectly straight. Please refer to the image below for proper wiring of the Squire.

Easiest, but not as tidy
1. Cut individual wires which span from switch to switch
2. Solder the wire to switches

Cleanest, but tougher to properly solder
1. Cut one entire length of wire from top switch to bottom
2. Solder the top switch connection to the wire
3. Use your solder to melt the plastic or get fancy with wire strippers where the next switch connection is located
4. Solder the wire to the switch, working your way down.

4. Wiring – Rows
Your rows are similar to the columns, however, they are obviously horizontal. You will need to solder the wire to each diode below the black band (cathode, negative). Please refer to the image below for proper wiring of the rows.

Easiest, but not as tidy
1. Cut individual wires which span from switch to switch
2. Solder the wire to switches

Cleanest, but tougher to properly solder
1. Cut one entire length of wire from top switch to bottom
2. Solder the top switch connection to the wire
3. Use your solder to melt the plastic where the next switch connection is located
4. Solder the wire to the switch, working your way down.

5. Wiring – Microcontroller (Pro Micro/Teensy)
You are almost done soldering! Each row and column needs to be connected to the correct pin in the microcontroller. You should wire your keyboard so the columns are all connected to pins next to one another, and typically the same for rows. Start with the columns. When you connect a row to the MC, make sure it’s not on a switch connection (needs to be below the black band of the diode).






Squire Pin Locations using a Pro Micro
0 – B3
1- B2
2 – B6
3 – D0
4- D4

0 – F4
1 – F5
2 – F6
3 – F7
4 – B1






Additionally, you may set up LED lighting for the Num Lock (D1) and optional back light control (B7). The supplied hex file is programmed to support LED lighting with 5 different brightness levels. I will add hand-wiring LED lighting to this guide at a later time.

-Optional- This makes flashing your Pro Micro immensely easier.
1. Cut two pieces of wire about 1″ length
2. Solder one wire to GND
3. Solder the other wire to RST
4. Solder these wires to the provided switch/button or your own. A full size Cherry switch will not fit once you put the case and plate together, but you can use it for flashing purposes. Please look at the image below for soldering to the correct terminals on the provided switch.

6. Mounting your Pro Micro
I use about .25″ of hot glue on the underside of top middle switch and press the Pro Micro so it’s parallel to the plate. It’s been strong enough to hold the Pro Micro on with plugging/unplugging a cable. Aside from a dedicated PCB, if you have a more elegant method, please let me know.

You will want to check to make sure the Micro USB port is in the middle of the hole.

This sums up hand wiring the Squire. In the next tutorial, I will go over flashing the Pro Micro.