Android app for local/remote control

[eadmaster]

i am looking for an Android app that provides an UI to control the arduino pins, much like the old ArduinoCommander app provided with Firmata.

Is there an alternative based on Telemetrix?

[MrYsLab]

It is interesting that you ask. I have been experimenting with flet and the Uno R4 WIFI. I have a working demo I can run on my Android tablet that uses WIFI to connect to the tablet. Then I can click a button to turn on an LED, use a slider to fade another LED, read a potentiometer and use the value read to adjust the angle of a servo, and an indicator for a slide switches current position. Here is a screenshot of the Android app.

And the flet code is very straight forward:

import flet as ft
import time
from telemetrix_uno_r4.wifi.telemetrix_uno_r4_wifi import telemetrix_uno_r4_wifi

"""
Demo: Control an Arduino UNO R4 WiFi over Wifi using Flet and Telemetrix
"""


def main(page: ft.Page):

    # ###################### Telemetrix callback functions
    def pot_callback(data):
        """
        Process the report for a potentiometer value change

        :param data: data[2] contains the reported potentiometer value
        """

        # if the latest value is different then the last
        # save the value, calculate the new servo position
        # and move the servo.
        if data[2] != page.session.get('last_pot_reading'):
            page.session.set('last_pot_reading', data[2])
            servo_angle = int(((data[2] * 180) / 1023))
            page.session.get('board').servo_write(page.session.get('servo_pin'),
                                                  servo_angle)
            # angle value is a text control
            angle_value.value = str(servo_angle)
            angle_value.update()

    def slide_switch_callback(data):
        """
        Process the report for a slide switch value change

        :param data: data[2] contains the reported potentiometer value
        """

        # The state of the slide switch is represented by an
        # icon control

        slide_sw_icon = page.session.get('slide_switch_icon')

        if data[2] == 0:
            slide_sw_icon.name = ft.icons.ARROW_LEFT_SHARP
            slide_sw_icon.color = ft.colors.RED
        else:
            slide_sw_icon.name = ft.icons.ARROW_RIGHT_SHARP
            slide_sw_icon.color = ft.colors.GREEN
        slide_sw_icon.update()

    # ################# flet control event handlers

    def ip_connect_button_clicked(e):
        """
        Process the IP connect button being pressed.
        Instantiate telemetrix-uno-r4 and connect to the
        Uno R4 Wi-Fi.

        :param e: connect elevated button event

        """
        if ip_uno.value:
            e.control.text = "Connecting..."
            e.control.bgcolor = 'amber'
            connect_button.update()
            try:
                board = telemetrix_uno_r4_wifi.TelemetrixUnoR4WiFi(
                    transport_address=ip_uno.value)
                # save the telemetrix instantiation object
                page.session.set('board', board)
            except OSError:
                # Invalid IP detected
                dlg = ft.AlertDialog(
                    title=ft.Text("Invalid IP Address"))
                # on_dismiss=lambda e: print("Dialog dismissed!"))
                page.dialog = dlg
                dlg.open = True
                page.update()
                return

            # the arduino is connected and ready to participate
            page.session.set('connected', True)
        else:
            # user did not fill in ip address
            dlg = ft.AlertDialog(
                title=ft.Text("No IP Address entered"))
            page.dialog = dlg
            dlg.open = True
            page.update()

    def led_button_clicked(e):
        """
        Toggle the LED button text and toggle the LED
        :param e: event
        """

        # toggle the text
        if e.control.text == "Click To Turn LED On":
            e.control.text = "Click to Turn LED Off"
            page.session.get('board').digital_write(page.session.get('blue_led_pin'), 1)
        else:
            e.control.text = "Click To Turn LED On"
            page.session.get('board').digital_write(page.session.get('blue_led_pin'), 0)

        # update the page to display change
        e.control.update()

    # event handler to set white led intensity level
    def white_led_slider_change(e):
        """
        Process a slider change. Adjust intensity of white LED based
        on slider position.
        :param e: event
        """
        page.session.get('board').analog_write(page.session.get('white_led_pin'),
                                               int(e.control.value))

    """
    ******************************************************
    ******************  MAIN PROGRAM *********************
    ******************************************************
    """

    page.padding = 50
    page.spacing = 50

    # ********** Set up session storage to avoid using globals

    # telemetrix instance - initially set to None
    page.session.set('board', None)

    # arduino pin numbers for connected devices
    page.session.set('blue_led_pin', 9)
    page.session.set('white_led_pin', 6)
    page.session.set('potentiometer_pin', 2)
    page.session.set('servo_pin', 5)
    page.session.set('slide_switch_pin', 13)

    # last potentiometer reading
    page.session.set('last_pot_reading', 0)

    # state of Wi-Fi connection to Arduino
    page.session.set('connected', False)

    # create a page title
    page.title = "Flet With Arduino UNO R4 WIFI Threaded Demo"

    # ###################create and display controls on the page

    # create a text field to capture user input for the IP address
    # of the Arduino.
    #
    # create a button for the user to submit the address.

    header = ft.Text("Flet With Arduino UNO R4 WIFI Threaded Demo",
                     theme_style=ft.TextThemeStyle.HEADLINE_MEDIUM,
                     weight=ft.FontWeight.BOLD)

    page.add(header)

    ip_uno = ft.TextField(label="Enter IP Arduino Address", autofocus=True)
    connect_button = ft.ElevatedButton(text="Connect", color="white", bgcolor="red",
                                       on_click=ip_connect_button_clicked)

    # do a little page layout magic
    ip_container = ft.Container(content=ip_uno)
    connect_row = ft.Row(spacing=5, controls=[ip_container, connect_button])

    page.add(connect_row)

    # get the current connection state
    # initially it will be False
    connected = page.session.get('connected')

    # connected will be set to True in the ip_connect_button_clicked
    # event handler. Wait for connection.
    while not connected:
        connected = page.session.get('connected')
        time.sleep(.00002)

    # we are now connected, so replace the connect button with a connected message.
    connect_row.controls = [ip_container, ft.Text("CONNECTED!", color="green",
                                                         size=20,
                                                  weight=ft.FontWeight.BOLD)]

    connect_row.update()

    # ##### Add the rest of the controls to the page

    # add the led toggle button
    led_button = ft.ElevatedButton(text="Click To Turn LED On", color="white",
                                   bgcolor="blue",
                                   on_click=led_button_clicked)

    # add a slider to fade the white LED
    white_led_slider = ft.Slider(min=0, max=255, divisions=255, label="{value}",
                                 on_change=white_led_slider_change)
    white_led_slider_legend = ft.Text('Set White LED Intensity')
    white_led_slider_legend.weight = ft.FontWeight.BOLD
    white_led_slider_legend.size = 16

    led_fade_row = ft.Row(spacing=10,
                          controls=[white_led_slider_legend, white_led_slider])

    # add a text control to display the current servo angle that is
    # set by manipulating a physical potentiometer
    angle_legend = ft.Text('Adjust Pot To Set Servo Angle:', size=16,
                           weight=ft.FontWeight.BOLD)
    angle_value = ft.Text('0', size=16,
                          weight=ft.FontWeight.BOLD)

    servo_row = ft.Row(spacing=10, controls=[angle_legend, angle_value])

    # Display the state of the slide switch on the arduino with
    # arrow icons.

    slide_switch_legend = ft.Text('Slide Switch Position:', size=16,
                                  weight=ft.FontWeight.BOLD)

    slide_switch_icon = ft.Icon(name=ft.icons.ARROW_LEFT_SHARP,
                                size=60, color=ft.colors.RED)

    page.session.set('slide_switch_icon', slide_switch_icon)

    slide_switch_row = ft.Row(spacing=10,
                              controls=[slide_switch_legend, slide_switch_icon])

    page.add(ft.Column(spacing=60, alignment=ft.alignment.bottom_left, controls=[
        led_button,
        led_fade_row,
        servo_row,
        slide_switch_row]))

    # set pin modes for devices in use
    page.session.get('board').set_pin_mode_digital_output(page.session.get('blue_led_pin'))
    page.session.get('board').set_pin_mode_digital_output(page.session.get('white_led_pin'))
    page.session.get('board').set_pin_mode_digital_input(page.session.get('slide_switch_pin'),
                                     callback=slide_switch_callback)
    page.session.get('board').set_pin_mode_analog_input(page.session.get('potentiometer_pin'),
                                    differential=4, callback=pot_callback)
    page.session.get('board').set_pin_mode_servo(page.session.get('servo_pin'))
    # set servo position to 0 degrees
    page.session.get('board').servo_write(page.session.get('servo_pin'), 0)

    page.update()

try:
    ft.app(target=main)
except RuntimeError:
    print('xxx')

However, since the telemetrix library for the Uno R3 and similar processors uses a Serial/USB transport, I am uncertain how this would work. I did create webpage controller using pymata-io This uses WebSockets. I believe Flet supports WebSockets, but I have yet to use them.

So, yes, it is possible to control an Arduino with an Android app, but I do not have anything available yet and do not have a timeframe for when one might be available.

If you want to implement a solution, I would be happy to provide any guidance you need.