XIAO RP2040 Mouse Ver 3.0
Over the last few months, We have been steadily improving the design of our XIAO RP2040-based mouse device. With this, ver 3.0 all the hardware bugs were finally eliminated, and we also placed the device into its first-ever enclosure.
Let us take a look at the design
The PCB and Schematic
The PCB is a very strange shape, with lots of cut-outs. This is to accommodate the big push buttons that will be mounted in the enclosure, as well as to fit nicely into the mounting area of the enclosure… This design took quite some time with a pair of callipers and CAD, but all went well, and the shape is perfectly accurate.
Schematic_RemoteMouse_2024-01-25Download
The schematic is also straight forward, with the only real changes begin to the rotary encoder. In ver 2.0, We connected the encoder to the MCP23008, but for some reason CircuitPython does not seem to like an encoder connected to an IO extender… That forced us to do some software hack to use the encoder… I have thus decided to change things around in ver 3.0 and move the encoder back to the native GPIO on the XIAO RP2040
It is also interesting to note that the circuit was initially designed for the XIAO ESP32S3, but due to issues with stock, as well as crazy prices on local parts, we made a quick turn-around and went back to the RP2040. The ESP32S3 was going to allow us to implement a wireless device, through using ESPNow protocol… That may still be done in future, but for now, I think we have done enough work on the mouse device for the time being…
Manufacturing the PCB and Assembly
The PCB for this project was sponsored by PCBWay .
Disclaimer:
Clicking on the PCBWay link will take you to the PCBWay website. It will enable you to get a $5.00 USD voucher towards your first PCB order. (Only if you sign up for a free account).
Assembly was quite easy, I chose to use a stencil, because the IO Expander chip has a very tiny footprint, as well as a leadless package… The stencil definitely helps prevent excessive solder paste, as well as saves a lot of time on reworking later…
In the picture above, we can clearly see why I had to design the PCB with such an irregular shape.
Firmware and Coding
We are still using CircuitPython for the firmware on this device. It is not perfect, but it works, well sort of anyway. What does that mean? Well… As far as the mouse functions are concerned, clicking, scrolling, moving the pointer – all of that is works perfectly, and thus allows me to use the device for basic operations every day. Drag and Drop, as well as selecting and or highlighting text DOES NOT work. This seem to be an issue with the HID code in Circuitpython, meaning it doesn’t seem to be implemented. It is also way beyond my abilities to implement it myself…
Below is the code.py file, with the boot.py below that
import time
import board
import busio
from rainbowio import colorwheel
import neopixel
import rotaryio
import microcontroller
from digitalio import Direction
from adafruit_mcp230xx.mcp23008 import MCP23008
import digitalio
i2c = busio.I2C(board.SCL, board.SDA)
mcp = MCP23008(i2c)
from analogio import AnalogIn
import usb_hid
from adafruit_hid.mouse import Mouse
joyX = board.A0
joyY = board.A1
JoyBtn = board.D2
LeftBtn = 0
CenterBtn = 1
RightBtn = 2
UpBtn = 3
DownBtn = 4
EncoderBtn = 5
mouse = Mouse(usb_hid.devices)
xAxis = AnalogIn(joyX)
yAxis = AnalogIn(joyY)
# NEOPIXEL
pixel_pin = board.NEOPIXEL
num_pixels = 1
pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=0.1, auto_write=False)
leftbutton = mcp.get_pin(LeftBtn)
leftbutton.direction = digitalio.Direction.INPUT
leftbutton.pull = digitalio.Pull.UP
centerbutton = mcp.get_pin(CenterBtn)
centerbutton.direction = digitalio.Direction.INPUT
centerbutton.pull = digitalio.Pull.UP
maint_btn = digitalio.DigitalInOut(JoyBtn)
maint_btn.switch_to_input(pull=digitalio.Pull.UP)
rightbutton = mcp.get_pin(RightBtn)
rightbutton.direction = digitalio.Direction.INPUT
rightbutton.pull = digitalio.Pull.UP
enc_btn = mcp.get_pin(EncoderBtn)
enc_btn.direction = digitalio.Direction.INPUT
enc_btn.pull = digitalio.Pull.UP
scroll_up = mcp.get_pin(UpBtn)
scroll_up.direction = digitalio.Direction.INPUT
scroll_up.pull = digitalio.Pull.UP
scroll_down = mcp.get_pin(DownBtn)
scroll_down.direction = digitalio.Direction.INPUT
scroll_down.pull = digitalio.Pull.UP
mousewheel = rotaryio.IncrementalEncoder(board.D6, board.D7, 4)
last_position = mousewheel.position
print(mousewheel.position)
move_speed = 3
enc_down = 0
RED = (255, 0, 0)
YELLOW = (255, 150, 0)
GREEN = (0, 255, 0)
CYAN = (0, 255, 255)
BLUE = (0, 0, 255)
PURPLE = (180, 0, 255)
BLACK = (0, 0, 0)
if move_speed == 0:
in_min, in_max, out_min, out_max = (0, 65000, -20, 20)
filter_joystick_deadzone = (
lambda x: int((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min)
if abs(x - 32768) > 500
else 0
)
if move_speed == 1:
pixels.fill(GREEN)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -15, 15)
filter_joystick_deadzone = (
lambda x: int((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min)
if abs(x - 32768) > 500
else 0
)
if move_speed == 2:
pixels.fill(BLUE)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -10, 10)
filter_joystick_deadzone = (
lambda x: int((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min)
if abs(x - 32768) > 500
else 0
)
if move_speed == 3:
pixels.fill(PURPLE)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -8, 8)
filter_joystick_deadzone = (
lambda x: int((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min)
if abs(x - 32768) > 500
else 0
)
if move_speed == 4:
pixels.fill(CYAN)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -5, 5)
filter_joystick_deadzone = (
lambda x: int((x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min)
if abs(x - 32768) > 500
else 0
)
pixels.fill(BLACK)
pixels.show()
while True:
# Set mouse accelleration ( speed)
#print(mousewheel.position)
if move_speed == 0:
pixels.fill(BLACK)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -20, 20)
filter_joystick_deadzone = (
lambda x: int(
(x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
)
if abs(x - 32768) > 500
else 0
)
if move_speed == 1:
pixels.fill(GREEN)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -15, 15)
filter_joystick_deadzone = (
lambda x: int(
(x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
)
if abs(x - 32768) > 500
else 0
)
if move_speed == 2:
pixels.fill(BLUE)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -10, 10)
filter_joystick_deadzone = (
lambda x: int(
(x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
)
if abs(x - 32768) > 500
else 0
)
if move_speed == 3:
pixels.fill(PURPLE)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -8, 8)
filter_joystick_deadzone = (
lambda x: int(
(x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
)
if abs(x - 32768) > 500
else 0
)
if move_speed == 4:
pixels.fill(CYAN)
pixels.show()
in_min, in_max, out_min, out_max = (0, 65000, -5, 5)
filter_joystick_deadzone = (
lambda x: int(
(x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
)
if abs(x - 32768) > 500
else 0
)
current_position = mousewheel.position
position_change = current_position - last_position
x_offset = filter_joystick_deadzone(xAxis.value) * -1 # Invert axis
y_offset = filter_joystick_deadzone(yAxis.value)
mouse.move(x_offset, y_offset, 0)
if enc_btn.value and enc_down == 1:
move_speed = move_speed + 1
if move_speed > 4:
move_speed = 0
# print (move_speed)
enc_down = 0
if not enc_btn.value:
enc_down = 1
if leftbutton.value:
mouse.release(Mouse.LEFT_BUTTON)
# pixels.fill(BLACK)
# pixels.show()
else:
mouse.press(Mouse.LEFT_BUTTON)
pixels.fill(GREEN)
pixels.show()
if centerbutton.value:
mouse.release(Mouse.MIDDLE_BUTTON)
else:
mouse.press(Mouse.MIDDLE_BUTTON)
pixels.fill(YELLOW)
pixels.show()
# Center button on joystick
if maint_btn.value:
mouse.release(Mouse.LEFT_BUTTON)
else:
mouse.press(Mouse.LEFT_BUTTON)
pixels.fill(GREEN)
pixels.show()
if rightbutton.value:
mouse.release(Mouse.RIGHT_BUTTON)
# pixels.fill(BLACK)
# pixels.show()
else:
mouse.press(Mouse.RIGHT_BUTTON)
pixels.fill(PURPLE)
pixels.show()
if not scroll_up.value:
mouse.move(wheel=1)
time.sleep(0.25)
pixels.fill(BLUE)
pixels.show()
if not scroll_down.value:
mouse.move(wheel=-1)
time.sleep(0.25)
pixels.fill(CYAN)
pixels.show()
if not scroll_up.value and not scroll_down.value:
for x in range(4):
pixels.fill(RED)
pixels.show()
time.sleep(0.5)
pixels.fill(BLACK)
pixels.show()
time.sleep(0.5)
microcontroller.reset()
if position_change > 0:
mouse.move(wheel=position_change)
#print(current_position)
#pixels.fill(BLUE)
#pixels.show()
elif position_change < 0:
mouse.move(wheel=position_change)
#print(current_position)
#pixels.fill(CYAN)
#pixels.show()
last_position = current_position
pixels.fill(BLACK)
pixels.show()
boot.py
import storage
import board, digitalio
import time
from rainbowio import colorwheel
import neopixel
import busio
from digitalio import Direction
from adafruit_mcp230xx.mcp23008 import MCP23008
import digitalio
i2c = busio.I2C(board.SCL, board.SDA)
mcp = MCP23008(i2c)
#button = digitalio.DigitalInOut(board.D8)
#button.pull = digitalio.Pull.UP
button = mcp.get_pin(6)
button.direction = digitalio.Direction.INPUT
button.pull = digitalio.Pull.UP
Rstbutton = mcp.get_pin(7)
Rstbutton.direction = digitalio.Direction.INPUT
Rstbutton.pull = digitalio.Pull.UP
# NEOPIXEL
pixel_pin = board.NEOPIXEL
num_pixels = 1
pixels = neopixel.NeoPixel(pixel_pin,num_pixels,brightness=0.2,auto_write=False)
RED = (255, 0, 0)
YELLOW = (255,150, 0)
GREEN = (0, 255, 0)
CYAN = (0, 255, 255)
BLUE = (0, 0, 255)
PURPLE = (180, 0, 255)
BLACK = (0, 0, 0)
# Disable devices only if button is not pressed.
#usb_hid.enable((), boot_device=2)
if button.value:
pixels.fill(GREEN)
pixels.show()
storage.disable_usb_drive()
usb_cdc.disable()
else:
pixels.fill(RED)
pixels.show()
usb_cdc.enable(console=True, data=False)
storage.enable_usb_drive()
time.sleep(5)
3D printing is still a distant dream… I bought it online, and then CNC cut the holes…
that case.
