Using rp2040 as a keyboard AND a mouse through micropython

[dov]

I'm working on writing a micropython program for the the Pico W to make it into a websocket controlled USB-keyboard and mouse. I'm using the the micropython-lib packages usb-device-keyboard and usb-device-mouse. The keyboard part now seem to be working and I wanted to add mouse support as well. But when initializing the mouse, the keyboard part stops working.

Here is how to reproduce the problem.

1. Install the dependent packages:

mpremote connect /dev/ttyACM0 mip install usb-device-mouse
mpremote connect /dev/ttyACM0 mip install usb-device-keyboard

2. Add the following to main.py:

import usb.device
from usb.device.keyboard import KeyboardInterface, KeyCode, LEDCode
from usb.device.mouse import MouseInterface
import time

time.sleep_ms(5000) # Sleep so that we can interrupt at start

kb = KeyboardInterface()
mouse = MouseInterface()
usb.device.get().init(kb, builtin_driver=True)
# usb.device.get().init(mouse, builtin_driver=True)   # <--- If I do this init, I can no longer send keyboard events!

# Send the character 'a' twice a second
while True:
    kb.send_keys([KeyCode.A])  # <--- This is only received if I don't init the mouse
    kb.send_keys([])
    time.sleep_ms(500)

3. Restart the MCU and wait for the incoming 'a' characters
4. Change main.py and uncomment the mouse initialization
5. Redo and verify that there are no incoming 'a' characters.

So my question is, how can I initialize both the keyboard AND the mouse?

My version of micropython is:

MicroPython v1.25.0 on 2025-04-15; Raspberry Pi Pico W with RP2040

[dov]

See also:

micropython/micropython-lib#921

I also copied in this question into github copilot, and the response that I got was more or less that it is currently not supported in micropython, and it offered to help me write a combined keyboard and mouse module.

Here's github copilot's summary:

In summary:

You cannot implement a true composite Keyboard+Mouse HID device for USB on RP2040 MicroPython using only Python and the current micropython-lib. It requires C-level changes or a custom firmware build.

Would you like guidance on how to approach the C-level changes, or are you interested in workarounds or alternative approaches?

So it doesn't look like it is possible to do my project in micropython at this time. :-(

[Cerothen]

I was taking a look at this project and found the following solution to work for my testing purposes. The LED assignments are just so that I can visually see what the current HID device is.

Basically we keep the current state of the HID device, then swap to the other one if needed which seems to work well enough in this example.

# Reference Material
# https://github.com/orgs/micropython/discussions/17475
# https://github.com/micropython/micropython-lib/blob/fbf7e120c6830d8d04097309e715bcab63dcca67/micropython/usb/examples/device/keyboard_example.py
# https://github.com/micropython/micropython-lib/blob/fbf7e120c6830d8d04097309e715bcab63dcca67/micropython/usb/examples/device/mouse_example.py


import usb.device
from usb.device.keyboard import KeyboardInterface, KeyCode, LEDCode
from usb.device.mouse import MouseInterface
import time
from machine import Pin

# Debugging Status Indication
mouseLED = Pin(15, Pin.OUT) # BLUE
keyboardLED = Pin(8, Pin.OUT) # GREEN

# Default LED States
mouseLED.on()
keyboardLED.off()

lastDevice = 0 # 0-NONE, 1-KEYBOARD, 2-MOUSE
defaultDelay = 150

print("Initializing")
for i in range(10):
    print(i)
    mouseLED.toggle()
    keyboardLED.toggle()
    time.sleep_ms(500)

# Default LED States
mouseLED.off()
keyboardLED.off()

print("Device Setup")
kb = KeyboardInterface()
mouse = MouseInterface()

def mouse_init():
    # Initialize Mouse If Needed
    global lastDevice
    if lastDevice != 2:
        usb.device.get().init(mouse, builtin_driver=True)
        while not mouse.is_open():
            time.sleep_ms(100)
        time.sleep_ms(250)
        lastDevice = 2
    keyboardLED.off()
    mouseLED.on()
        
def kb_init():
    # Initialize Mouse If Needed
    global lastDevice
    if lastDevice != 1:
        usb.device.get().init(kb, builtin_driver=True)
        while not kb.is_open():
            time.sleep_ms(100)
        time.sleep_ms(250)
        lastDevice = 1
    mouseLED.off()
    keyboardLED.on()

def mouse_left_click(leftRight=1, hold=0):
    mouse_init()
    if leftRight == 0:
        mouse.click_left(False)
        mouse.click_right(False)
    elif leftRight == 1:
        mouse.click_left(True)
        time.sleep_ms(100)
        if hold == 0:
            mouse.click_left(False)
    elif leftRight == 2:
        mouse.click_right(True)
        time.sleep_ms(100)
        if hold == 0:
            mouse.click_right(False)
    time.sleep_ms(defaultDelay)

def mouse_move(posX, posY):
    mouse_init()
    mouse.move_by(posX, posY)
    time.sleep_ms(defaultDelay)

def send_key(keyVal):
    kb_init()
    kb.send_keys([keyVal])
    kb.send_keys([])
    time.sleep_ms(defaultDelay)


mouse_move(-100,0)
mouse_move(0,100)
mouse_move(100,0)
mouse_move(0,-100)

send_key(KeyCode.A)
send_key(KeyCode.B)
send_key(KeyCode.C)
send_key(KeyCode.D)

mouse_move(-100,0)
mouse_move(0,100)
mouse_move(100,0)
mouse_move(0,-100)

send_key(KeyCode.A)
send_key(KeyCode.B)
send_key(KeyCode.C)
send_key(KeyCode.D)