rM5StickCPlus2

B4R Library rM5StickCPlus2

Brief
rM5StickPlus2 is an open-source library for the M5 StickC-Plus2.

This library

has been developed for M5 StickC-Plus devices with dedicated functionality to be integrated in author's Smart Home, like Solar Battery Monitor, CO-Sensor Living Room, Quick Info Display, but also to be used in other creations.
is partially wrapped from the M5Stack libraries (MIT license) M5Unified, M5GFX.
is enhanced with custom functions & constants covering LCD control, Buttons (A Big in the middle, B Small top left, C Small bottom right Power) event, Battery management.
has been developed to display text and dedicated graphics (like battery state icon) only.
does not support following device features IMU, speaker, buzzer, MIC, IR emitter.
is in an early stage - not all functions tested; functions might change.

Development Info

Written in C++ - Arduino IDE 2.3.6, Arduino CLI 1.2.2 and the B4Rh2xml tool.
Arduino IDE Library dependencies:
- M5Unified 0.2.10, M5GFX 0.2.15.
B4R Additional libraries used in the examples (download from this forum):
- rESP8266WiFi 1.60, rDFRobot_MultiGasSensor 1.00, rConvert 1.40.
Tested with
- Hardware - M5 StickC-Plus, M5 StickC-Plus2.
- Software - B4R 4.00 (64-bit).

M5 StickC-Plus2 Features

Micro-controller: ESP32-PICO-V3-02 240MHz dual core,support WiFi,2 MB SPI PSRAM,8 MB SPI flash.
Power Input: 5V @ 500mA.
Ports: USB Type-C, GROVE (I2C + I/0 + UART).
Display: 1.14-inch Colorful TFT LCD screen, resolution 135 x 240 pixels, driver ST7789v2.
Battery: built-in 200mAh @ 3.7V LiPo battery, rechargeable via USB Type-C port.
Buttons: Button A (BtnA), Button B (BtnB), Button Power (BtnPWR).
IMU: Integrated MPU6886 6-axis IMU for motion detection and orientation sensing.
LED: Green LED (non-programmable) (sleep status indicator).
RED LED: (same control pin GPIO19 as infrared transmitter tube).
Buzzer: built-in buzzer, MIC: SPM1423, RTC: BM8563.
PIN ports: GPIO0, GPIOG25/GPIO36, GPIO26, GPIO32, GPIO33.
Antenna: 2.4G 3D Antenna.

Screenshots from some of the examples

Files
The rM5StickCPlus2-NNN.zip archive contains the library and sample projects.

Install
Copy the rM5StickCPlus2 library folder from the archive into your B4R Additional Libraries folder, keeping the folder structure intact.

Wiring
See examples.

Function Overview (one-liners)

Initialize - Initializes the M5 core and power module.
InitializeWithButtonEvent - Initializes the M5 core and power module with button event.
InitializeWithRTC - Initializes the RTC, M5 core and power module.
Clear - Clears the LCD screen using the default background color.
ClearColor - Clears the LCD screen and sets a new color.
ClearArea - Clears a rectangular area with the current background color.
ClearTextArea - Clears a rectangular area with the current background color.
SetBrightness - Sets the backlight brightness in the range 0-255.
SetCursor - Sets the text cursor position.
SetTextSize - Sets the text size multiplier (only affects bitmap fonts).
SetTextColor - Sets the text color for all subsequent prints.
Print - Prints a string at the current cursor position.
PrintCentered - Prints text centered at (xCenter, y) with optional background.
PrintNum - Prints a floating-point number with 2 decimal places.
PrintNumDecimals - Prints a floating-point number with the given decimal places.
SetTextAt - Prints a string at a specific screen position.
GetTextLengthInPixel - Gets the length of a string in pixels.
SetHeader - Displays a header text at the top of the screen, with optional background clearing.
SetFooter - Displays a footer text at the bottom of the screen, with optional background clearing.
SetHorLine - Draws a horizontal line at the specified Y position.
UpdateFontMetrics - Updates the current font metrics.
GetFontWidth - Gets the approximate width of the current font in pixels.
GetFontHeight - Gets the height of the current font in pixels.
SetFreeFont - Sets the free font (ignores SetTextSize and has a fixed scale).
SetTextFont - Sets the current text font (1–4) and scaling factor.
SetDigitFont - Sets a large numeric font (6–8) optimized for displaying digits.
SetFontDefault - Resets the LCD to the default font.
DrawRect - Draws a rectangle.
FillRect - Draws a filled rectangle.
DrawRoundRect - Draws a rectangle with rounded corners.
FillRoundRect - Draws a filled rectangle with rounded corners.
DrawCircle - Draws a circle.
FillCircle - Draws a filled circle.
DrawLine - Draws a line between two points.
StartWrite - Starts writing to the LCD.
EndWrite - Ends writing to the LCD.
GetWidth - Gets the width of the LCD.
GetHeight - Gets the height of the LCD.
GetCenterX - Gets the center X position of the LCD.
GetCenterY - Gets the center Y position of the LCD.
IsPortrait - Checks if the display is in portrait mode.
ButtonA_Pressed - Checks whether Button A is currently pressed.
ButtonB_Pressed - Checks whether Button B is currently pressed.
BatteryLevel - Returns the battery charge level.
BatteryVoltage - Returns the current battery voltage.
IsBatteryLow - Checks whether the battery is considered low.
IsBatteryCritical - Checks whether the battery is considered critical.
BatteryCheck - Performs battery health check and optionally powers off if voltage too low.
DrawBattery - Draws a small battery icon at top right with optional percentage and tiny outlined battery level bar.
SetLed - Sets the state of the power LED.
PowerOff - Powers the device off.
RTC_IsEnabled - Checks if the RTC is enabled.
RTC_SetDateTime - Sets the RTC date and time.
RTC_SetDate - Sets the RTC date.
RTC_SetTime - Sets the RTC time.
RTC_UpdateDateTime - Updates internal date and time variables from the RTC.
RTC_Date - Gets the current date (1–31).
RTC_Month - Gets the current month (1–12).
RTC_Year - Gets the current year (2000 + NNN).
RTC_Hour - Gets the current hour (0–23).
RTC_Minute - Gets the current minute (0–59).
RTC_Second - Gets the current second (0–59).
RTC_DayOfWeek - Gets the current day of week (0–6).
RTC_GetTimeString - Gets the current time as formatted string.
RTC_GetDateString - Gets the current date as formatted string.
RTC_SetDateTimeFromNTP - Gets the date and time from the NTP server and sets the class vars.
DrawIconBattery - Draws a battery icon with level indicator.
DrawIconWiFi - Draws a Wi-Fi signal icon.
DrawIconSolar - Draws a simple solar icon.
DrawIconGrid - Draws a grid (power) icon.
DrawIconTemp - Draws a temperature icon.

Examples

Basic - Print the string Hello World and more (see below Basic Example).
Buttons - Test the buttons A (big button), B (top left), PWR (bottom right).
BatteryCheck - Check the battery level and if below threshold, shut the M5StickCPlus2 down.
RTC - Real Time Clock test with time set manually and display showing time & date updated every second via timer.
RTCNTP - Real Time Clock test with time set from NTP server and display showing time & date updated every second.
COSensor - Reads CO gas concentration, VO voltage, and on-board temperature from a CO-sensor.
COSensorHomeAssistant - Reads CO gas concentration, VO voltage, and on-board temperature from a CO-sensor connected to the M5StickCPlus2 and publish to Home Assistant (HA).
PowerPanelHomeAssistant - Sent in regular interval (60s) a HTTP GET request to the Home Assistant (HA) server, parse the response containing solar data and display.
Fonts - Show some of the built-in fonts.
Icons - Show icon examples.

Basic Example

B4X:

Sub Process_Globals
    Public Serial1 As Serial
    Private m5 As M5StickCPlus2
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("[Main.AppStart]")

    ' Init the device
    m5.Initialize
    Log("[Main.AppStart][I] M5 initialized.")
 
    ' Show the red led beside the button power
    m5.SetLed(True)
 
    ' Display mode landscape (power supply right)
    m5.Rotation = m5.M5_ROTATION_LANDSCAPE
    Log("[Main.AppStart][I] Rotation portrait=", m5.IsPortrait)

    m5.SetHeader("Basic Demo", 2, m5.UI_ALIGN_CENTER, m5.COLOR_GREEN, m5.COLOR_BLACK, True)
    m5.SetHorLine((m5.GetFontHeight * 2), m5.COLOR_WHITE, 2)

    ' LCD Display
    Log("[Main.AppStart][I] LCD width/height=", m5.GetWidth,"/",m5.GetHeight)
    ' [Main.AppStart][I] LCD width/height=240/135
 
    Log("[Main.AppStart][I] LCD center x/y=", m5.GetCenterX, "/", m5.GetCenterY)
    ' [Main.AppStart][I] LCD center x/y=120/67
 
    ' Text size 1 (default)
    Log("[Main.AppStart][I] Textsize 1 width/height=", m5.GetFontWidth, "/", m5.GetFontHeight)
    ' [Main.AppStart][I] Textsize 3 width/height=18/24
 
    ' Text size 3
    m5.SetTextSize(3)
    Log("[Main.AppStart][I] Textsize 3 width/height=", m5.GetFontWidth, "/", m5.GetFontHeight)
    ' [Main.AppStart][I] Textsize 3 width/height=18/24

    m5.SetTextColor(m5.COLOR_WHITE)
    m5.SetTextAt(20, 50, "Hello World", 3, m5.COLOR_WHITE)
 
    ' Text length for text size 3 (font width 18) and text hello world (11 characters)
    Log("[Main.AppStart][I] Textsize 3 'Hello World' length=", m5.GetTextLengthInPixel("Hello World"))
    ' [Main.AppStart][I] Textsize 3 'Hello World' length=198
    ' 198 = 11 characters * font width 18
 
    ' Set text centered X at lcd bottom
    m5.SetHorLine(m5.GetHeight - (m5.GetFontHeight * 1), m5.COLOR_WHITE, 1)
    m5.SetFooter("rStickCPlus2", 1, m5.UI_ALIGN_CENTER, m5.COLOR_GREEN, m5.COLOR_RED, True)
End Sub

To Do

Improve example PanelPanelHomeAssistant and publish as B4R Creation (also on GitHub). Place the device on the Solar Battery as Indicator.

Credits

M5 for the M5Stack Open Source libraries (here).

Disclaimer

This project is developed for personal use only.
All examples and code are provided as-is and should be used at your own risk.
Any guidance provided as-is, without any guarantee or liability for errors, omissions, or wrong configurations.
Always test thoroughly and exercise caution when connecting hardware components.

Licenses

rM5StickCPlus2: MIT License (see LICENSE file).

Last edited: Oct 23, 2025

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B4R Library rM5StickCPlus2

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rwblinn

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