Working with Arduino

This chapter contains the following sections. Please read as needed:

Arduino Getting Started
Setting Up Development Environment
Demo V1.0
Demo V2.0

Arduino Getting Started

New to Arduino ESP32 development and looking for a quick start? We have prepared a comprehensive Getting Started Tutorial for you.

Note: This tutorial uses the ESP32-S3-Zero as a reference example, and all hardware code is based on its pinout. Before you start, we recommend checking the pinout of your development board to ensure the pin configuration is correct.

Setting Up Development Environment

Install and Configure Arduino IDE

Please refer to the tutorial Installing and Configuring Arduino IDE to download and install the Arduino IDE and add ESP32 support.

Version 1.0

Board Name	Board Installation Requirement	Version Requirement
esp32 by Espressif Systems	"Install Offline" / "Install Online”	3.0.2 ≤ Version ≤ 3.1.1

Install Libraries

When installing Arduino libraries, there are typically two methods: Install Online and Install Offline. If the library installation requires Install Offline, you must use the provided library file.
For most libraries, users can easily search for and install them via the Arduino IDE's online Library Manager. However, some open-source or custom libraries are not synchronized to the Arduino Library Manager and therefore cannot be found through online search. In this case, users can only install these libraries manually via offline methods.
The sample program package for the ESP32-S3-Touch-LCD-1.85 development board can be downloaded from here. The Arduino\libraries directory within the package already contains all the library files required for this tutorial.

Library/File Name	Description	Version	Installation Method
LVGL	Graphics Library	v8.3.10	"Install Offline”
ESP32-audioI2S-master	Audio Decoding Library	v2.0.0	"Install Offline”

Version 2.0

Board Name	Installation Requirement	Version Requirement
esp32 by Espressif Systems	"Install Offline" / "Install Online”	3.2.0

Install Libraries

When installing Arduino libraries, there are typically two methods: Install Online and Install Offline. If the library installation requires Install Offline, you must use the provided library file.
For most libraries, users can easily search for and install them via the Arduino IDE's online Library Manager. However, some open-source or custom libraries are not synchronized to the Arduino Library Manager and therefore cannot be found through online search. In this case, users can only install these libraries manually via offline methods.
The sample program package for the ESP32-S3-Touch-LCD-1.85 development board can be downloaded from here. The Arduino\libraries directory within the package already contains all the library files required for this tutorial.

Library/File Name	Description	Version	Installation Method
LVGL	Graphics Library	v9.3.0	"Install Offline”
ESP32-audioI2S-master	Audio Decoding Library	v2.0.0	"Install Offline”
ES7210	Audio Encoding Library	-	"Install Offline"
ES8311	Audio Decoding Library	-	"Install Offline"

Version Compatibility Notes

There are strong dependencies between versions of LVGL and its driver libraries. For example, a driver written for LVGL v8 may not be compatible with LVGL v9. To ensure that the examples can be reproduced reliably, it is recommended to use the specific versions listed in the table above. Mixing different versions of libraries may lead to compilation failures or runtime errors.

Arduino Project Parameter Settings

If the example being flashed contains a speech recognition model, select "ESP SR 16M (3MB APP/7MB SPIFFS/2.9MB MODEL)" for the Partition Scheme.
If the example being flashed does not contain a speech recognition model, select "16M Flash (3MB APP/9.9MB FATFS)" or another appropriate scheme.

Demo-v1

LVGL_Arduino

Demo Description

This demo demonstrates the functionality of various onboard devices. Page 1 displays parameters such as SD Card, Flash Size, Battery Voltage, etc., while Page 2 is the music playback interface. Additionally, this example includes voice recognition functionality.

Hardware Connection

Insert the TF card into the development board
Connect the speaker to the development board
Connect the development board to the computer

Code Analysis

setup(): Hardware initialization, configuring peripherals, etc.
- Hardware Initialization: setup() mainly executes several initialization functions to configure and initialize hardware components connected to the Arduino, such as RTC, gyroscope, LCD display, TF card, audio module, microphone, etc. Through these initializations, it ensures the hardware can function correctly.
- GUI Initialization: Calls Lvgl_Init() to initialize LVGL (Light and Versatile Graphics Library), a widely used graphics library for embedded systems. Lvgl_Example1() is an example program used to demonstrate how to render a graphical interface on the display.
- Task Scheduling: The Driver_Loop() function creates a task (DriverTask) for managing and cyclically executing operations for some peripherals.
loop(): Mainly used for GUI updates and task scheduling.
- LVGL Task Loop: Lvgl_Loop() is a loop function of the LVGL library, used to handle GUI updates, event responses, and other UI-related operations. In embedded systems, graphics libraries typically need to be called frequently in the main loop to maintain screen refresh and real-time interactivity.
- Task Scheduling Control: vTaskDelay(pdMS_TO_TICKS(5)) pauses the task for 5 milliseconds. vTaskDelay is a delay function in FreeRTOS, aiming to reduce CPU usage, avoid occupying too much time slice, and ensure other system tasks (such as peripheral processing) can execute on time.

Operation Result

LCD Screen Display

LCD Screen Display Parameter Description

Parameter	Function	Description
SD Card	Displays the TF card size	Connect a TF card. If recognition fails, please format the TF card to FAT32 (if initial recognition fails, wait a moment and then reset to check again)
Flash Size	Displays the Flash size	Onboard 16MB Flash
Battery Voltage	Battery voltage	Battery voltage can be detected when a battery is connected
Angular deflection	Displays the board's angular deviation	Displays deviation in three directions
RTC Time	Displays RTC time	Displays the current RTC time The RTC time may not match the current time because data cannot be retained when power is off. To keep the RTC time accurate, you need to connect an RTC battery and update the RTC time
Wireless scan	Displays the number of Wi-Fi networks scanned	"..OK" will be displayed at the end of the scan
Backlight brightness	Brightness slider	Adjusts screen brightness

Page 2 is the UI page for playing mp3 audio files located in the root directory of the TF card
This program enables voice recognition by default. The wake word is "hi esp". After waking up, the backlight dims, and you can speak the command (if the backlight does not dim, it means it was not woken up; recognition requires standard pronunciation and a slower speaking pace)
Several MIC test audio formats are provided below (Note: if the "hi esp" wake-up fails, please reposition the audio to the point where the wake word is played and try again)
Please do not perform voice recognition while audio is being played through the speaker
The reason the test audio plays the wake word twice is that the current firmware version requires a focus step for the first wake-up (metaphorically), and the current firmware does not allow disabling this feature
```
  // Commands
  Turn on the backlight
  Turn off the backlight
  Backlight is brightest
  Backlight is darkest
```

Demo-v2

The Arduino demos are located in the Arduino/examples directory of the demo package.

Demo	Basic Program Description	Dependency Library
01_lvgl_example	Demonstrates basic LVGL graphics library functionality, also useful for testing display basics and random text rendering	LVGL
02_RTC_PCF85063	RTC Clock Test	-
03_audio_out_no_tf	Audio Playback Test	ESP32-audioI2S-master
04_SDMMC_Test	TF Card Mount Test	-
05_audio_out_tf	TF Card Audio Playback Test	ESP32-audioI2S-master
06_AnalogRead	ADC Read Battery Voltage	-
07_WiFi_http_Client	WIFI Connection and HTTP GET Test	-
08_esp_sr	Voice Wake-up and Voice Recognition Function Test	-

01_lvgl_example

Demo Description

This example demonstrates the functionality of LVGL Widgets. Different demos can be switched in the code to view the effects.

Hardware Connection

Connect the development board to the computer

Code Analysis

setup: Responsible for initializing various hardware devices and the LVGL graphics library environment
- I²C Bus Initialization: I2C_Init() initializes the I²C bus for communication with other I²C devices
- I/O Expander Initialization: Creates and initializes the I/O expander TCA9554PWR_Init(0x00);, sets pin modes to output, and performs some initial pin state configurations
- Backlight Initialization: Initializes the PWM controller Backlight_Init();
- Graphics Display Initialization: Initializes the graphics display device LCD_Init();, then initializes LVGL, including registering a print callback function for debugging, initializing the display driver and input device driver. Creates and starts the LVGL timer, and finally calls lv_demo_widgets() to demonstrate LVGL's example widgets

Operation Result

LCD Screen Display

02_RTC_PCF85063

Demo Description

This example demonstrates the functionality of the Real-Time Clock PCF85063A, retrieving the time every second and printing the current time to the serial port.

Hardware Connection

Connect the development board to the computer

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- I²C Bus Initialization: I2C_Init() initializes the I²C bus for communication with other I²C devices
- PCF85063 Chip Initialization: PCF85063_Init();
loop:
- Reads Real-Time Clock data: IPCF85063_Loop();
- Converts the data to a string and prints it to the LOG: PCF85063_Loop();

Operation Result

View the serial monitor

03_audio_out_no_tf

Demo Description

This example demonstrates how to initialize audio peripherals and play music.

Hardware Connection

Connect the development board to the computer

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- I²C Bus Initialization: I2C_Init() initializes the I²C bus for communication with other I²C devices
- Initializes the ES8311 audio decoder chip: es8311_codec_init();
- Initializes the I2S peripheral: setupI2S();
- Initializes the PA pin and sets it high: pinMode(15, OUTPUT);digitalWrite(15, HIGH); GPIO15 controls the amplifier enable output
loop:
- Reads audio data and outputs it to the ES8311 via I2S: i2s.write((uint8_t *)audio_data, AUDIO_SAMPLES * 2);

Operation Result

This example has no screen display or LOG output
After flashing the code, the audio will play in a loop

04_SDMMC_Test

Demo Description

This example demonstrates TF card mounting, prints TF card type information, and tests file reading and writing.

Hardware Connection

Connect the development board to the computer
Insert a TF card

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- Initializes SDIO pins: SD_MMC.setPins(clk, cmd, d0)
- Mounts the TF card: SD_MMC.begin("/sdcard", true)
- Gets the TF card type: SD_MMC.cardType();
- Gets the TF card capacity: SD_MMC.cardSize()
- Tests file writing: writeFile(SD_MMC, "/hello.txt", "Hello ");

Operation Result

View the serial monitor

05_audio_out_tf

Demo Description

This example demonstrates mounting a TF card and reading audio files from the TF card for playback.

Hardware Connection

Connect the development board to the computer
Insert a TF card with an MP3 file

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- I²C Bus Initialization: I2C_Init() initializes the I²C bus for communication with other I²C devices
- Mounts the TF card: sdmmc_init();
- Initializes the ES8311 audio decoder chip: es8311_codec_init();
- Initializes audio I2S peripheral pins: audio.setPinout(I2S_BCK_PIN, I2S_LRCK_PIN, I2S_DOUT_PIN,I2S_MCLK_PIN);
- Sets the playback path: audio.connecttoFS(SD_MMC, "ff-16b-1c-44100hz.mp3");
- Initializes the PA pin and sets it high: pinMode(15, OUTPUT);digitalWrite(15, HIGH); GPIO15 controls the amplifier enable output
loop:
- Audio processing: audio.loop();

Operation Result

This example has no screen display or LOG output
After flashing the code, the audio will play in a loop

06_AnalogRead

Demo Description

This example demonstrates reading raw ADC values and battery voltage via ADC.

Hardware Connection

Connect the development board to the computer
Insert a battery
The power switch needs to be turned on

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- Initializes ADC peripheral: analogReadResolution(12);
loop:
- Gets raw ADC value: analogRead(8);
- Gets the converted actual voltage value: analogReadMilliVolts(8);
- Prints battery voltage: Serial.printf("BAT millivolts value = %d\n", analogVolts*3);. The battery voltage is detected via a resistor divider before being fed into the ADC

Operation Result

View the serial monitor

07_WiFi_http_Client

Demo Description

This example demonstrates Wi-Fi connection and obtaining JSON data via the HTTP GET method.

Hardware Connection

Connect the development board to the computer

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Sets the SSID for connection: const char *ssid = "WSTEST";
- Sets the PASSWORD for connection: const char *password = "waveshare0755";
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- Wi-Fi initialization and connection: WiFi.begin(ssid, password);
- Prints IP address upon successful connection: Serial.println(WiFi.localIP());
loop:
- Connects to HTTP server: client.connect(host, httpPort);
- Gets the response: readResponse(&client);

Operation Result

View the serial monitor

08_esp_sr

Demo Description

This example demonstrates the voice wake-up and voice recognition features of ESP-SR.

Hardware Connection

Connect the development board to the computer

Code Analysis

setup: Responsible for initializing various hardware peripherals
- Serial initialization: USerial.begin(115200); prepares for serial debugging
- Initializes I2C: Wire.begin(I2C_PIN_SDA, I2C_PIN_SCL);
- ES7210 encoder initialization: es7210_init();
- Sets I2S pins: i2s.setPins(I2S_PIN_BCK, I2S_PIN_WS, I2S_PIN_DOUT, I2S_PIN_DIN, I2S_PIN_MCK);
- Initializes I2S peripheral: i2s.begin(I2S_MODE_STD, 16000, I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO);
- Sets voice wake-up and recognition event: ESP_SR.onEvent(onSrEvent);
- Initializes the ESP-SR speech recognition module: ESP_SR.begin(i2s, sr_commands, sizeof(sr_commands) / sizeof(sr_cmd_t), SR_CHANNELS_STEREO, SR_MODE_WAKEWORD);
onSrEvent(sr_event_t event, int command_id, int phrase_id): ESP-SR voice recognition callback event
- Connects to HTTP server: client.connect(host, httpPort);
- Gets the response: readResponse(&client);

Operation Result

View the serial monitor

Switch between Chinese/English Recognition Models

The initial state of the environment defaults to the English recognition environment. Follow the steps below to switch to the Chinese recognition model or revert to the English recognition model.

Switch to Chinese Recognition Model

Building the Chinese Recognition Environment

Download the provided program file Demo Using Chinese Model
Navigate to the path C:\Users\Waveshare\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\ESP_SR\src (where Waveshare is the computer username)
Replace the esp32-hal-sr.c file in this path with the downloaded file
Download the Chinese model Chinese Model - Wake Word 'hi lexin'
Navigate to the path C:\Users\Waveshare\AppData\Local\Arduino15\packages\esp32\tools\esp32-arduino-libs\idf-release_v5.1-bd2b9390ef\esp32s3\esp_sr (where Waveshare is the computer username)
Replace the srmodels.bin file in this path with the downloaded file
Modify the recognition commands in the demo to Chinese commands (Pinyin)

Switching to English Recognition Model

The initial state of the environment defaults to the English recognition environment. If it has not been switched to Chinese, do not perform the following modifications
If it was previously modified for Chinese recognition, download the provided program file Demo Using English Model(https://files.waveshare.com/wiki/common/Use_the_English_model_program.zip)
Navigate to the path C:\Users\Waveshare\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.0.2\libraries\ESP_SR\src (where Waveshare is the computer username)
Replace the esp32-hal-sr.c file in this path with the downloaded file
Download the English model English Model - Wake Word 'hi esp’
Navigate to the path C:\Users\Waveshare\AppData\Local\Arduino15\packages\esp32\tools\esp32-arduino-libs\idf-release_v5.1-bd2b9390ef\esp32s3\esp_sr (where Waveshare is the computer username)
Replace the srmodels.bin file in this path with the downloaded file
Modify the recognition commands in the demo to English commands (phonemes)

Give Feedback

Arduino Getting Started​

Setting Up Development Environment​

Install and Configure Arduino IDE​

Version 1.0​

Install Libraries​

Version 2.0​

Install Libraries​

Arduino Project Parameter Settings​

Demo-v1​

LVGL_Arduino​

Demo Description​

Hardware Connection​

Operation Result​

Demo-v2​

01_lvgl_example​

02_RTC_PCF85063​

03_audio_out_no_tf​

04_SDMMC_Test​

05_audio_out_tf​

06_AnalogRead​

07_WiFi_http_Client​

08_esp_sr​

Switch between Chinese/English Recognition Models​

Arduino Getting Started

Setting Up Development Environment

Install and Configure Arduino IDE

Version 1.0

Install Libraries

Version 2.0

Install Libraries

Arduino Project Parameter Settings

Demo-v1

LVGL_Arduino

Demo Description

Hardware Connection

Operation Result

Demo-v2

01_lvgl_example

02_RTC_PCF85063

03_audio_out_no_tf

04_SDMMC_Test

05_audio_out_tf

06_AnalogRead

07_WiFi_http_Client

08_esp_sr

Switch between Chinese/English Recognition Models