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Raspberry Pi Pico 4x4 Macropad

Raspberry Pi Pico 4x4 Macropad

As seen on the Tindie Blog! as well as on the Adafruit Blog

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Description​

This is a 4x4 Keyboard/keypad/macropad kit for you to build a 16 key macropad with a Raspberry Pi Pico. All you need are 16 MX mechanical switches and keycaps and about an hour for assembly.

Entering the Bootloader & flashing CircuitPython​

Firmware​

Libraries needed​

You need to download the Adafruit CircuitPython Bundle 7.x from the CircuitPython Libraries page.

Uncompress it and copy the library called adafruit_hid to the lib folder of your macropad.

Code​

Copy the following to code.py

# SPDX-FileCopyrightText: 2021 Pierre Constantineau
# SPDX-License-Identifier: MIT
# Raspberry Pi Pico 4x4 Macropad 
"""
    Code adapted from the following sources:
    MACROPAD Hotkey (https://learn.adafruit.com/macropad-hotkeys/project-code)
    Pico Four Keypad  (https://learn.adafruit.com/pico-four-key-macropad/code-the-four-keypad)
"""
import board
import keypad
import usb_hid
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keycode import Keycode
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS

kpd = Keyboard(usb_hid.devices)
keyboard_layout = KeyboardLayoutUS(kpd)

# define keys for 4x4 v1
keys = keypad.KeyMatrix(
    row_pins=(board.GP0, board.GP1, board.GP2, board.GP3),
    column_pins=(board.GP4, board.GP5, board.GP6, board.GP7),
    columns_to_anodes=True,
)


keymap = [
    ("Select all", [Keycode.LEFT_CONTROL, Keycode.A]),
    ("Cut", [Keycode.LEFT_CONTROL, Keycode.X]),
    ("Copy", [Keycode.LEFT_CONTROL, Keycode.C]),
    ("Paste", [Keycode.LEFT_CONTROL, Keycode.V]),
    ("Hello World", "Hello World"),
    ("Cut", [Keycode.LEFT_CONTROL, Keycode.X]),
    ("Copy", [Keycode.LEFT_CONTROL, Keycode.C]),
    ("Paste", [Keycode.LEFT_CONTROL, Keycode.V]),
    ("Select all", [Keycode.LEFT_CONTROL, Keycode.A]),
    ("Cut", [Keycode.LEFT_CONTROL, Keycode.X]),
    ("Copy", [Keycode.LEFT_CONTROL, Keycode.C]),
    ("Paste", [Keycode.LEFT_CONTROL, Keycode.V]),
    ("Select all", [Keycode.LEFT_CONTROL, Keycode.A]),
    ("Cut", [Keycode.LEFT_CONTROL, Keycode.X]),
    ("Copy", [Keycode.LEFT_CONTROL, Keycode.C]),
    ("Paste", [Keycode.LEFT_CONTROL, Keycode.V])
]

print("keymap:")
for key in keymap:
    print("\t", key[0])

while True:
    key_event = keys.events.get()
    if key_event:  
        if key_event.pressed:
            print(keymap[key_event.key_number][0])
            sequence = keymap[key_event.key_number][1]
            for item in sequence:
                if isinstance(item, int):
                    if item >= 0:
                        kpd.press(item)
                    else:
                        kpdrelease(-item)
                else:
                    keyboard_layout.write(item)
        else:
            # Release any still-pressed modifier keys
            for item in sequence:
                if isinstance(item, int) and item >= 0:
                    kpd.release(item)

Schematic​

schematic

PCB​

Top of PCB​

Bottom of PCB​

Build Instructions - Summarized​

Bottom PCB

  • Solder RPI Pico on bottom plate

Top PCB

  • Solder Diodes on Top Plate - make sure that the band on the diode is near the heavier line of on the silkscreen - or the square pad (depends on the top plate)

diodes

Join Top/Bottom PCB

  • Cut the headers and sockets in group of 4.
  • Join/connect the Header and Socket groups together
  • Line up the top/bottom PCB so that the sockets are all on the same side (top or bottom - I usually have the pins at the bottom)
  • make sure that the top plate can be read and has the same orientation as the bottom plate (Need pictures)
  • Solder the Sockets
  • Solder the pins

Solder Switches

  • Disconnect the top/bottom PCB making sure to pull straight not to bend the pins
  • Install the switches through the PCB. If you have a switch plate (a grid) push the switches through the switch plate as you install them on the PCB
  • Inspect that all switch pins go through the PCB.
  • Solder the switches
  • Reconnect the Top/Bottom PCB
  • Install keycaps

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