nunchuk_mouse.py

# SPDX-FileCopyrightText: Copyright (c) 2022 esp32beans@gmail.com
#
# SPDX-License-Identifier: MIT

""" Convert Wii Nunchuk to USB mouse with two buttons. """

import array
import math
import board
import adafruit_nunchuk
import usb_hid

from adafruit_hid.mouse import Mouse

JS_DEBUG = 0
DEADZONE = 1
X_SPEED = 3.0   # Also known as sensitivity
Y_SPEED = 3.0   # Also known as sensitivity

mouse = Mouse(usb_hid.devices)

# This should work for all boards with STEMMA connectors.
i2c = board.STEMMA_I2C()

if board.board_id in ('adafruit_qt2040_trinkey', 'adafruit_qtpy_rp2040',
        'adafruit_feather_rp2040'):
    i2c.try_lock()
    i2c.scan()
    i2c.unlock()

nc = adafruit_nunchuk.Nunchuk(i2c)


# Experiment with mouse acceleration/sensitivity. For small deflections of the
# joystick move the mouse slowly. For larger deflections, move the mouse
# faster. The look up table is computed outside the main loop to avoid calling
# time consuming the math function on every loop. The X and Y tables use the
# same values but could use different values.
X_ACCEL = array.array('B')
Y_ACCEL = array.array('B')

for x in range(128):
    if x <= DEADZONE:
        # Dead zone around center to fix drift.
        # Joysticks do not alway report (x=0,y=0) when the stick is released.
        # When this happens the cursor moves slowly when it should not be moving.
        # This is sometimes called drifting. Drifting is fixed by treating
        # joystick values between -DEADZONE to +DEADZONE as 0. If the cursor is
        # still drifting increase the value of DEADZONE.
        X_ACCEL.append(0)
        Y_ACCEL.append(0)
    else:
        X_ACCEL.append(int((math.pow(x/127.0, X_SPEED) * 127) + 0.5))
        Y_ACCEL.append(int((math.pow(x/127.0, Y_SPEED) * 127) + 0.5))
        if x > 0:
            if X_ACCEL[x] == 0:
                X_ACCEL[x] = 1
            if Y_ACCEL[x] == 0:
                Y_ACCEL[x] = 1
    if JS_DEBUG:
        print(x, X_ACCEL[x], Y_ACCEL[x])

# The index into this array goes from 0 to 128 so make the last element
# have the same value as the element 127.
X_ACCEL.append(X_ACCEL[127])
Y_ACCEL.append(Y_ACCEL[127])

LAST_JS_X = 255
LAST_JS_Y = 255

while True:
    x, y = nc.joystick
    if JS_DEBUG:
        js_x = x
        js_y = y
    # Map the range 0 to 255 from the joystick to -127 to 128 for the mouse.
    x = x - 127
    y = -(y - 127)
    if JS_DEBUG:
        signed_x = x
        signed_y = y

    if x < 0:
        x = -X_ACCEL[abs(x)]
    else:
        x = X_ACCEL[abs(x)]

    if y < 0:
        y = -Y_ACCEL[abs(y)]
    else:
        y = Y_ACCEL[abs(y)]
    if JS_DEBUG:
        sensitivity_x = x
        sensitivity_y = y

    if JS_DEBUG and (LAST_JS_X != js_x or LAST_JS_Y != js_y):
        print(js_x, js_y, signed_x, signed_y, sensitivity_x, sensitivity_y)
        LAST_JS_X = js_x
        LAST_JS_Y = js_y
    mouse.move(x, y)

    if nc.buttons.C:
        mouse.press(Mouse.LEFT_BUTTON)
    else:
        mouse.release(Mouse.LEFT_BUTTON)
    if nc.buttons.Z:
        mouse.press(Mouse.RIGHT_BUTTON)
    else:
        mouse.release(Mouse.RIGHT_BUTTON)