ESP32 Formats and Communication: Application of Communication Protocols with ESP32 Microcontroller (Maker Innovations Series)

Although Wi-Fi communication is incorporated in many internet-based applications, knowledge of alternative communication protocols is vital for optimal project development with a microcontroller, such as the ESP32. This book focuses on communication protocols for the ESP32 microcontroller with illustrative projects ranging from a Bluetooth Low Energy beacon communicating with your smart wristwatch to Long Range (LoRa) communication between microsatellites circling 550km above the Earth and an ESP32 microcontroller in your home. Just as there are different communication protocols, there are different ESP32 microcontroller formats. You’ll examine the features of several ESP32 microcontroller formats, which enable the optimal combination of communication protocol and ESP32 format to achieve the requirements of a project. Several of the communication protocols and ESP32 formats have only been available in the last few months or years, making the book very relevant. Each chapter focuses on a communication protocol and is stand-alone, so they can be read without having to start from the beginning of the book. The chapters are loosely grouped into short- and long-range communication, image management for transmission to a webpage or a remote LCD screen, and the required apps and IoT techniques for remote control of an ESP32-CAM robot vehicle. The advantages of each communication protocol correspond to different project types. What You'll Learn Study the MESH communication protocol and the ESP-NOW protocol with communication between ESP32 microcontrollers without a Wi-Fi connection Review email communication projects with an ESP32 and generation of quick response codes to instruct an ESP32 to control a connected device. Look at the ESP32-CAM module built around a 2M-pixel camera for streaming images with the WebSocket protocol to a remote ESP32 Control an ESP32-CAM robot car through remote communication over the internet with image streaming to an Android tablet or mobile phone. Who This Book Is For Table of Contents 6 About the Author 13 About the Technical Reviewer 14 Preface 15 Chapter 1: ESP32 Microcontroller 18 USB to UART Driver Installation 20 Arduino IDE 21 esp32 Boards Manager Version 2.0.N 22 ESP32 DEVKIT DOIT 26 TTGO T-Display V1.1 28 Pulse-Width Modulation 30 Analog to Digital Conversion 30 TTGO LoRa32 V2.1 1.6 36 TTGO T-Watch V2 39 TTGO T-Watch Installation 40 M5Stack Core2 41 M5Stack Core2 Installation 44 M5Stack Core2 and Sound 46 M5Stack Core2 M5GO Battery Base 50 ESP32-CAM 51 ESP32-CAM-MB Module 54 ESP32-CAM-CH340 Module 55 Image Resolution 56 Microcontroller Developments 58 Memory 61 Heap Memory 62 Non-volatile Memory 68 Software Versions 71 Chapter 2: I2S Audio 72 Analog to Digital 72 Direct Memory Access 76 PDM Microphone 77 Fast Fourier Transform 84 Digital to Analog 93 PCM5102 Decoder Module 93 MAX98357 Decoder Module 94 Internet Radio 97 Internet Radio with an ESP32 Module 97 Internet Radio with M5Stack Core2 102 MP3 Player 113 Play MP3 Files from the Micro-SD Card 113 Play MP3 Files with M5Stack Core2 118 Bluetooth Communication 126 Transmission to ESP32 126 Transmission by ESP32 131 Bluetooth Device Scanning 138 Chapter 3: MESH Communication 140 ESP-MESH 140 ESP-MESH and One Bluetooth Device 151 ESP-MESH and Bluetooth Apps 153 Chapter 4: TTGO T-Watch V2 161 TTGO T-Watch Functionality 161 Configuration File 164 Main Sketch 165 Default Display Screen 169 Application Menu 172 Screen Brightness 175 GPS Information 177 GPS Location 180 Speed, Altitude, and Distance Covered 182 GPS Satellite Map 186 Bluetooth Communication 192 Infrared Signaling 195 Synchronization with the Network Time Protocol 201 Source OpenWeatherMap API Data 205 Step Counter and Distance Measure 209 Timer 213 Battery Voltage and Microcontroller Temperature 217 Data Storage on a Micro-SD Card 220 Temperature, Current, and Screen Brightness 221 GPS Tracking Data 225 Factory Firmware Installation 229 Chapter 5: BLE Beacons 232 Eddystone Beacons 233 Eddystone-URL Beacon 239 Eddystone-TLM Beacon 241 Eddystone-UID Beacon 243 iBeacon 245 Beacon Raw Data 246 BLE Communication 248 GATT Profile 250 Two-Way Communication 257 Notifications 260 BLE Scanning 266 BLE Receive App 268 nRF24L01 Module as a BLE Transceiver 274 Chapter 6: LoRa and Microsatellites 282 ESP32 as a LoRa Transmitter or Receiver 283 ESP32 and LoRa Satellites 294 Installation and Configuration 295 Test Station Configuration and Test Message 298 Antenna for LoRa Reception 301 Microsatellite Tracking 302 Chapter 7: Email and QR Codes 307 Email 307 QR Codes 317 HTTP and XML HTTP Requests 320 QR Codes and XML HTTP Requests 328 QR Codes and WebSocket 333 Chapter 8: WebSocket, Remote Access, and OTA 339 WebSocket 339 Strings and Character Arrays 348 WebSerial 351 Web Dashboard 353 Over the Air (OTA) 360 Chapter 9: MQTT 364 CO2 and TVOC 365 MQTT, CO2, and TVOC 368 MQTT and Smart Meter 374 Energy Usage Measurement 375 Wi-Fi, MQTT, and Smart Meter 378 Wi-Fi Connection to a Router 383 ESP-NOW, MQTT, and Smart Meter 384 Wi-Fi or Wi-Fi and ESP-NOW 395 Chapter 10: Managing Images 398 Image Bitmap 399 Display a Black-and-White Image 402 Display a Color Image 408 Bitmap and X Bitmap 411 Send an Image in Email 415 Store the Image File in SPIFFS 417 Image URL in the Sketch 423 Display Images as a Sprite 428 LCD Screen 429 M5Stack Core2 and Accelerometer 432 Transparent Sprite 437 Memory Requirements 444 Display Time with Sprites 447 Extension to M5Stack Core2 455 Compress HTML Code 456 Chapter 11: ESP32-CAM Camera 460 Stream Images Directly to an LCD Screen 461 Stream Images to a Remote LCD Screen 467 Stream Images to TTGO T-Watch 475 Stream Images to M5Stack Core2 476 Stream Images Over Wi-Fi 477 Web Page with Control Functions 483 WebSocket 484 esp_http_server 493 Web Page with Image Streaming and Control Functions 498 ESP32-CAM Image Resolution 499 Chapter 12: Control Apps 502 App to Display a Web Page 503 App to Display Streamed Images 504 App to Transmit and Receive Data 510 App with Image Streaming and Control Functions 515 App Sliders 523 Circular Slider 524 Vertical Slider 528 Horizontal Slider Touchdown and Touchup 532 App to Control WS2812 RGB LEDs 534 Bluetooth Communication 535 Wi-Fi Communication 543 Chapter 13: Remote Control Motors 548 Servo Motor 548 ledc Function 549 ESP32Servo Library 551 App to Control a Servo Motor 555 DC Motors 561 TB6612FNG Motor Driver Board 566 L298N Motor Driver Board 570 Motor Driver Control 574 App to Control DC Motors with a Heading Angle 577 Motor Speed Variation 586 Chapter 14: Remote Control an ESP32-CAM Robot Car 589 App with Direction Buttons 592 App with Heading Angle Control 605 Chapter 15: Libraries 616 TFT_eSPI Library 616 Library Functions 617 Fonts 619 Libraries to Access Time Data 624 time Library 624 RTC Library 627 TimeLib and NTPtimeESP Libraries 629 System Time Library 631 Libraries Used 632 Create a Library 636 Source File 640 Header File 641 Keyword File 643 Information File 644 Components 646 Index 648