David Barrett
Published

Mobility Control Assistant

A core device, which can be added to a wheelchair or strapped to the body, allowing control tailored to each user.

AdvancedFull instructions provided258

Things used in this project

Hardware components

nRF52 Development Kit
Nordic Semiconductor nRF52 Development Kit
×1
AtomS3
M5Stack AtomS3
×1
Seeed Studio XIAO ESP32S3 Sense
Seeed Studio XIAO ESP32S3 Sense
×1
UNIHIKER - IoT Python Programming Single Board Computer with Touchscreen
DFRobot UNIHIKER - IoT Python Programming Single Board Computer with Touchscreen
×1

Software apps and online services

CircuitPython

Hand tools and fabrication machines

3D Printer (generic)
3D Printer (generic)

Story

Read more

Custom parts and enclosures

Mobility Gaming Aid

Mounts to use the device on a wheelchair or attache to a limb

Schematics

M5Stack ATOMS3 Wiring

Nordic nRF52840 DK Wiring

This is how you can wire modules to Nordic Semiconductor's nRF52840 DK

Seeed Studio XIAO ESP32S3 Sense + Grove Shield Wiring

This is how you can use Seeed Studio's kit (XIAO ESP32S3 Sense + Grove Shield for Xiao)

DFRobot Unihiker

Just plug in the DFRobot UNIHIKER and you are good to go.

Code

Main code for the device

MicroPython
This is the code.py file for use in CircuitPython
# SPDX-FileCopyrightText: 2024 Michał Pokusa
#
# SPDX-License-Identifier: Unlicense

import socketpool
import wifi
import board
import time
import busio
from adafruit_bus_device.i2c_device import I2CDevice
from mpu6886 import MPU6886
import struct
import busio  # type: ignore (This too!)
from joystick_xl.inputs import Axis, Button, Hat
from joystick_xl.joystick import Joystick
from joystick import JoystickUnit

from adafruit_httpserver import Server, Route, as_route, REQUEST_HANDLED_RESPONSE_SENT, Request, Response, GET, POST

AP_SSID = "MC"
AP_PASSWORD = "helpmemove"

print("Creating access point...")
wifi.radio.start_ap(ssid=AP_SSID, password=AP_PASSWORD)
print(f"Created access point {AP_SSID}")

pool = socketpool.SocketPool(wifi.radio)
server = Server(pool, "/static", debug=True)

sampling_ms = 150
minChange = 5

# Axis configuration constants
AXIS_DB = 5
AXIS_MIN = -255  # Minimum raw axis value.
AXIS_MAX = 255 # Maximum raw axis value.
factor = 25

# Axis configuration constants
THUMB_MIN = -128  # Minimum raw axis value.
THUMB_MAX = 128 # Maximum raw axis value.
THUMB_DB = 0 # Deadband to apply to axis center points.

# IMU6866 define
MPU6886_ADDRESS=0x68

i2c = busio.I2C(board.IMU_SCL, board.IMU_SDA)
i2c2 = busio.I2C(board.D1, board.D2) //An I2C device must be plugged in or pullups added
imu = I2CDevice(i2c, MPU6886_ADDRESS)
lcd = board.DISPLAY
jhat = ""
assert i2c2.try_lock()
if 0x52 in i2c2.scan():
    i2c2.unlock()
    jhat = JoystickUnit(i2c2, 0x52)
    jhat.swap_x(1)

sensor = MPU6886(i2c)

hotas = Joystick()

hotas.add_input(
    Button(),
    Axis(deadband=125, min=-255, max=255),
    Axis(deadband=125, min=-255, max=255),
    Axis(deadband=THUMB_DB, min=THUMB_MIN, max=THUMB_MAX),
    Axis(deadband=THUMB_DB, min=THUMB_MIN, max=THUMB_MAX),
)


FORM_HTML_TEMPLATE = """
<html lang="en">
    <head>
        <title>Form with {enctype} enctype</title>
    </head>
    <body>
        <h2>Please adjust the Joystick Settings</h2>
        <form action="/form" method="post" enctype="{enctype}">
            <p>Sample Rate (ms): <span id="sV">{SampleVal}</span> </p>
            <input type="range" min="10" max="500" value="{SampleVal}" id="Sample" name="Sample">
            <p>Minimum Range:<span>{MinValDisp}</span></p>
            <input type="range" min="-255" max="255" value="{MinValDisp}" id="MinVal" name="MinVal">
            <p>Maximum Range:<span>{MaxValDisp}</span></p>
            <input type="range" min="-255" max="255" value="{MaxValDisp}" id="MaxVal" name="MaxVal">
            <p>Minimum Motion Change:<span id="ra">{ChangeVal}</span></p>
            <input type="range" min="1" max="50" value="{ChangeVal}" id="Change" name="Change">
            <p>Set Deadband:<span id="dB">{DeadbandVal}</span></p>
            <input type="range" min="0" max="100" value="{DeadbandVal}" id="Deadband" name="Deadband">
            <p>Motion Options</p>
            <input type="radio" name="Motion" id="RelativeMotion" value="RelativeMotion" checked="checked"> Relative Motion
            <input type="radio" name="Motion" id="ChangeInMotion" value="ChangeInMotion"> Change in Motion<br>
            <br><input type="submit" value="Submit">
        </form>
        {submitted_value}
    </body>
</html>
"""


@server.route("/", [GET, POST])
def form(request: Request):
    """
    Serve a form with the given enctype, and display back the submitted value.
    """
    global sampling_ms
    global AXIS_MIN # Minimum raw axis value.
    global AXIS_MAX # Maximum raw axis value.
    global AXIS_DB # Deadband Change minimum.
    global minChange
    enctype = request.query_params.get("enctype", "text/plain")

    if request.method == POST:
        sampling_ms = int(request.form_data.get("Sample"))
        AXIS_MIN = int(request.form_data.get("MinVal"))
        AXIS_MAX = int(request.form_data.get("MaxVal"))
        minChange = int(request.form_data.get("Change"))
        AXIS_DB = int(request.form_data.get("Deadband"))
        posted_Motion = request.form_data.get("Motion")

    return Response(
        request,
        FORM_HTML_TEMPLATE.format(
            enctype=enctype,
            submitted_value=(
                "<h3>Updated</h3>"
                # f"<h3>Submitted form Sample: {sampling_ms}ms</h3>\n<h3>Submitted form Range: {minChange}</h3>\n<h3>Submitted form Deadband: {posted_Deadband}</h3>\n<h3>Submitted form motion: {posted_Motion}</h3>"
                if request.method == POST
                else ""
            ),
            MinValDisp=(
                f"{AXIS_MIN}"
                if request.method == POST
                else f"{AXIS_MIN}"
            ),
            MaxValDisp=(
                f"{AXIS_MAX}"
                if request.method == POST
                else f"{AXIS_MAX}"
            ),
            SampleVal=(
                f"{sampling_ms}"
                if request.method == POST
                else f"{sampling_ms}"
            ),
            ChangeVal=(
                f"{minChange}"
                if request.method == POST
                else f"{minChange}"
            ),
            DeadbandVal=(
                f"{AXIS_DB}"
                if request.method == POST
                else f"{AXIS_DB}"
            ),
        ),
        content_type="text/html",
    )


server.start(str(wifi.radio.ipv4_address_ap))

while True:

    try:
        gyro_array = sensor.gyro()
        accel_array = sensor.acceleration()
        DB = AXIS_MIN + (AXIS_MAX - AXIS_MIN)/2
        X = int(accel_array[0]*factor)
        if X > AXIS_MIN and X < AXIS_MAX:
            if X > DB-AXIS_DB and X < DB+AXIS_DB:
                hotas.axis[0].source_value = 125
            # print(f"X: {X}")
            elif X < hotas.axis[0].source_value - minChange or X > hotas.axis[0].source_value + minChange:
                hotas.axis[0].source_value = X
        Y = 0-int(accel_array[1]*factor)
        if Y > AXIS_MIN and Y < AXIS_MAX:
            if Y > DB-AXIS_DB and Y < DB+AXIS_DB:
                hotas.axis[1].source_value = 125
            elif Y < hotas.axis[1].source_value - minChange or Y > hotas.axis[1].source_value + minChange:
                hotas.axis[1].source_value = Y
        if jhat:
            X = jhat.get_x()
            if X > AXIS_MIN/2 and X < AXIS_MAX/2:
                if X > DB/2-AXIS_DB and X < DB/2+AXIS_DB:
                    hotas.axis[2].source_value = 0
                    # print(f"X: {X}")
                elif X < hotas.axis[2].source_value - minChange or X > hotas.axis[2].source_value + minChange:
                    hotas.axis[2].source_value = X
            Y = jhat.get_y()
            if Y > AXIS_MIN/2 and Y < AXIS_MAX/2:
                if Y > DB/2-AXIS_DB and Y < DB/2+AXIS_DB:
                    hotas.axis[3].source_value = 0
                    # print(f"X: {X}")
                elif Y < hotas.axis[3].source_value - minChange or Y > hotas.axis[3].source_value + minChange:
                    hotas.axis[3].source_value = Y
                hotas.button[0].source_value = 1 - jhat.get_button_status()
        hotas.update()
        # print(jhat.get_x())
        # print(accel_array)

                # Process any waiting requests
        pool_result = server.poll()

        if pool_result == REQUEST_HANDLED_RESPONSE_SENT:
            # Do something only after handling a request
            pass

        time.sleep(sampling_ms/1000)

        # If you want you can stop the server by calling server.stop() anywhere in your code
    except OSError as error:
        print(error)
        continue

Boot File

MicroPython
This is the boot.py file for use in CircuitPython
"""JoystickXL standard boot.py."""

import usb_hid  # type: ignore (this is a CircuitPython built-in)
from joystick_xl.hid import create_joystick

# This will enable all of the standard CircuitPython USB HID devices along with a
# USB HID joystick.
usb_hid.enable(
    (
        usb_hid.Device.KEYBOARD,
        usb_hid.Device.MOUSE,
        usb_hid.Device.CONSUMER_CONTROL,
        create_joystick(axes=4, buttons=1),
    )
)

Mobility Control Asistant

You will find all the additional libraries needed for this project and my latest code in GitHub

Credits

David Barrett

David Barrett

4 projects • 3 followers
I have a Bachelor of Technology (Computer Technology) from Latrobe University and I keep myself up to date with the latest technology.

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