Rename project.

+ Refactor most classes to header only.

README.md

@@ -3,7 +3,7 @@
 This repository is a collection of useful code snippets and configurations.
 
 ```bash
-github.com/shaunrd0/klips/
+shaunrd0/klips/
 ├── ansible     # Ansible roles, playbooks, and examples
 ├── blockchain  # Blockchain related project templates and examples
 ├── cpp         # C++ programs, datastructures, and other examples
@@ -12,6 +12,6 @@ github.com/shaunrd0/klips/
 ├── figlet      # Figlet fonts I like :)
 ├── javascript  # Javascript projects and examples
 ├── python      # Python scripts and tools I've made
-├── README.md
-└── scripts     # Bash scripts
+├── scripts     # Bash scripts
+└── README.md
 ```

esp/cpp/01_led-button/README.md

@@ -1,5 +1,9 @@
 # 01_led-button
 
+This example is largely adapted from those in [ESP32-basic-starter-kit.pdf](./ESP32-basic-starter-kit.pdf).
+
+The APIs in the original examples paired with this PDF have changed, and I decided to do some different things with the code and/or circuits, but the original code can be [found here](https://www.dropbox.com/scl/fo/6znlij3eb23ih4jxcpv2w/AKvB1t9CCUgoVRVtGen8Yrw?rlkey=z84anl0hs940qf9fpl7l8q8q2&e=1&dl=0).
+
 ![schematic](./schematic.png)
 
 Simple LED controlled by an on-board button.

esp/cpp/02_led-button-web/README.md

@@ -1,5 +1,9 @@
 # 02_led-button-web
 
+This example is largely adapted from those in [ESP32-basic-starter-kit.pdf](./ESP32-basic-starter-kit.pdf).
+
+The APIs in the original examples paired with this PDF have changed, and I decided to do some different things with the code and/or circuits, but the original code can be [found here](https://www.dropbox.com/scl/fo/6znlij3eb23ih4jxcpv2w/AKvB1t9CCUgoVRVtGen8Yrw?rlkey=z84anl0hs940qf9fpl7l8q8q2&e=1&dl=0).
+
 ![schematic](./schematic.png)
 
 This example uses the same schematic as [01_led-button](../01_led-button/).

esp/cpp/03_temp-humidity-web/README.md

@@ -1,5 +1,9 @@
 # 03_temp-humidity-web
 
+This example is largely adapted from those in [ESP32-basic-starter-kit.pdf](./ESP32-basic-starter-kit.pdf).
+
+The APIs in the original examples paired with this PDF have changed, and I decided to do some different things with the code and/or circuits, but the original code can be [found here](https://www.dropbox.com/scl/fo/6znlij3eb23ih4jxcpv2w/AKvB1t9CCUgoVRVtGen8Yrw?rlkey=z84anl0hs940qf9fpl7l8q8q2&e=1&dl=0).
+
 ![schematic](./schematic.png)
 
 Temperature and humidity sensor served on a web page within the local network.

esp/cpp/04_esp-idf-arduino/.gitignore

@@ -0,0 +1,4 @@
+build
+managed_components
+dependencies.lock
+sdkconfig.old

esp/cpp/04_esp-idf-arduino/CMakeLists.txt

@@ -0,0 +1,18 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.26)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+project(
+    #[[NAME]]   esp-idf-arduino
+    VERSION     0.1
+    DESCRIPTION "Example ESP-IDF cmake project"
+    LANGUAGES   CXX
+)
+
+# For writing pure cmake components, see the documentation
+# https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/build-system.html#writing-pure-cmake-components
+idf_build_set_property(COMPILE_OPTIONS "-Wno-error" APPEND)

esp/cpp/04_esp-idf-arduino/README.md

@@ -0,0 +1,81 @@
+# 04_esp-idf-arduino
+
+There is no schematic for this example, it simply prints some output to the serial monitor at 115200.
+This is more of a build system example for untethering yourself from the Arduino IDE.
+
+To build this example you can run the following commands.
+
+```bash
+# See Dependencies section below for instructions.
+source ~/path/to/esp-idf/export.sh
+
+mkdir build
+cd build
+cmake ..
+make -j $(nproc)
+
+# Flash the example to the ESP.
+make flash
+
+# Check the serial monitor for 'Hello world!' output.
+idf.py monitor -b 115200
+```
+
+To flash to your ESP or access the `idf.py menuconfig` menu from the ESP-IDF you can run the same commands with `make`.
+
+```bash
+make flash
+make menuconfig
+```
+
+If Ninja is preferred:
+
+```bash
+mkdir build
+cd build
+cmake .. -G Nina
+ninja
+```
+
+## Dependencies
+
+Install the [ESP-IDF](https://github.com/espressif/esp-idf?tab=readme-ov-file#setup-build-environment)
+
+```bash
+# https://docs.espressif.com/projects/esp-idf/en/v5.3.2/esp32/get-started/linux-macos-setup.html#for-linux-users
+sudo apt-get install -y git wget flex bison gperf python3 python3-pip python3-venv cmake ninja-build ccache libffi-dev libssl-dev dfu-util libusb-1.0-0
+
+git clone -b v5.3.2 --recursive https://github.com/espressif/esp-idf
+cd esp-idf
+./install.sh
+. ./export.sh
+```
+
+In CLion there is an official [Serial Monitor](https://plugins.jetbrains.com/plugin/8031-serial-port-monitor) plugin, or use ESP-IDF -
+
+```bash
+idf.py monitor -b 115200
+```
+
+## Starting Over
+
+To set up this project from scratch the following commands were used
+
+```bash
+# My example project directory
+cd ~/Code/klips/esp/cpp/04_esp-idf-arduino
+idf.py set-target esp32
+idf.py add-dependency "espressif/arduino-esp32^3.1.1"
+
+# Autostart Arduino for use of `loop()` and `setup()` functions
+# You can also use the esp-idf `app_main()` function if preferred
+# https://docs.espressif.com/projects/arduino-esp32/en/latest/esp-idf_component.html#configuration
+# You can alternatively do this in the GUI tool `idf.py menuconfig`
+echo "CONFIG_AUTOSTART_ARDUINO=y" >> sdkconfig
+sed -i -e 's/CONFIG_FREERTOS_HZ=100/CONFIG_FREERTOS_HZ=1000/' sdkconfig
+
+# Build the project
+idf.py build
+```
+
+To set this project up in CLion, see [JetBrains documentation](https://www.jetbrains.com/help/clion/esp-idf.html#env-vars).

esp/cpp/04_esp-idf-arduino/main/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(
+    SRCS "main.cpp"
+    INCLUDE_DIRS "."
+)

esp/cpp/04_esp-idf-arduino/main/idf_component.yml

@@ -0,0 +1,17 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  espressif/arduino-esp32: ^3.1.1

esp/cpp/04_esp-idf-arduino/main/main.cpp

@@ -0,0 +1,10 @@
+#include "Arduino.h"
+
+void setup() {
+  Serial.begin(115200);
+}
+
+void loop() {
+  Serial.println("Hello world!");
+  delay(1000);
+}

esp/cpp/05_temp-humidity-web/.gitignore

@@ -0,0 +1,4 @@
+build
+managed_components
+dependencies.lock
+sdkconfig.old

esp/cpp/05_temp-humidity-web/CMakeLists.txt

@@ -0,0 +1,18 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.26)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+project(
+    #[[NAME]]   temp-humidity-web
+    VERSION     0.1
+    DESCRIPTION "Temperature and humidity from DHT sensor served on a web page"
+    LANGUAGES   CXX
+)
+
+# For writing pure cmake components, see the documentation
+# https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/build-system.html#writing-pure-cmake-components
+idf_build_set_property(COMPILE_OPTIONS "-Wno-error" APPEND)

esp/cpp/05_temp-humidity-web/README.md

@@ -0,0 +1,27 @@
+# 05_temp-humidity-web
+
+This is the same example in [03_temp-humidity-web](./../03_temp-humidity-web), ported to the cmake ESP-IDF build system.
+
+For instructions on setting up the ESP-IDF see [04_-esp-idf-arduino](./../04_esp-idf-arduino)
+
+This example is largely adapted from those in [ESP32-basic-starter-kit.pdf](./ESP32-basic-starter-kit.pdf).
+
+The APIs in the original examples paired with this PDF have changed, and I decided to do some different things with the code and/or circuits, but the original code can be [found here](https://www.dropbox.com/scl/fo/6znlij3eb23ih4jxcpv2w/AKvB1t9CCUgoVRVtGen8Yrw?rlkey=z84anl0hs940qf9fpl7l8q8q2&e=1&dl=0).
+
+![schematic](./schematic.png)
+
+Temperature and humidity sensor served on a web page within the local network.
+
+![screenshot](./screenshot.png)
+
+To build this example run the following commands.
+
+```bash
+source ~/path/to/esp-idf/export.sh
+
+mkdir build
+cd build
+cmake ..
+make -j $(nproc)
+make flash
+```

esp/cpp/05_temp-humidity-web/main/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(
+    SRCS "main.cpp"
+    INCLUDE_DIRS "."
+)

esp/cpp/05_temp-humidity-web/main/idf_component.yml

@@ -0,0 +1,19 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  espressif/arduino-esp32: ^3.1.1
+  zorxx/dht: ^1.0.1
+  esp32async/espasyncwebserver: ^3.7.0~1

esp/cpp/05_temp-humidity-web/main/main.cpp

@@ -0,0 +1,189 @@
+#include "WiFi.h"
+#include "ESPAsyncWebServer.h"
+#include "main.h"
+
+// Replace with your network credentials
+const char *ssid = "wifi";
+const char *password = "password";
+
+#define DHTPIN GPIO_NUM_4  // Digital pin connected to the DHT sensor
+
+// Uncomment the type of sensor in use:
+#define DHTTYPE      DHT_TYPE_DHT11  // DHT 11
+//#define DHTTYPE    DHT_TYPE_DHT22  // DHT 22 (AM2302)
+//#define DHTTYPE    DHT_TYPE_DHT21  // DHT 21 (AM2301)
+
+float DHT::readTemperature(bool f)
+{
+  float humidity = 0;
+  float temperature = 0;
+  esp_err_t result = dht_read_float_data(type_, gpio_, &humidity,
+                                         &temperature);
+  if (result == ESP_OK) {
+    ESP_LOGI("[DHT::readTemperature]", "Humidity: %.1f%% Temperature: %.1f°C",
+             humidity,
+             temperature);
+  } else {
+    ESP_LOGE("[DHT::readTemperature]", "Failed to read sensor data: %s",
+             esp_err_to_name(result));
+  }
+  return f ? (temperature * 1.8f) + 32 : temperature;
+}
+
+float DHT::readHumidity()
+{
+  float humidity = 0;
+  float temperature = 0;
+  esp_err_t result = dht_read_float_data(type_, gpio_, &humidity,
+                                         &temperature);
+  if (result == ESP_OK) {
+    ESP_LOGI("[DHT::readTemperature]", "Humidity: %.1f%% Temperature: %.1f°C",
+             humidity,
+             temperature);
+  } else {
+    ESP_LOGE("[DHT::readTemperature]", "Failed to read sensor data: %s",
+             esp_err_to_name(result));
+  }
+  return humidity;
+}
+
+DHT dht(DHTPIN, DHTTYPE);
+
+// Create AsyncWebServer object on port 80
+AsyncWebServer server(80);
+
+String readDHTTemperature()
+{
+  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
+  float t = dht.readTemperature();
+  // Check if any reads failed and exit early (to try again).
+  if (isnan(t)) {
+    Serial.println("Failed to read from DHT sensor!");
+    return "--";
+  } else {
+    Serial.println(t);
+    return String(t);
+  }
+}
+
+String readDHTHumidity()
+{
+  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
+  float h = dht.readHumidity();
+  if (isnan(h)) {
+    Serial.println("Failed to read from DHT sensor!");
+    return "--";
+  } else {
+    Serial.println(h);
+    return String(h);
+  }
+}
+
+const char index_html[] PROGMEM = R"rawliteral(
+<!DOCTYPE HTML><html>
+<head>
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.2/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous">
+  <style>
+    html {
+     font-family: Arial;
+     display: inline-block;
+     margin: 0px auto;
+     text-align: center;
+    }
+    h2 { font-size: 3.0rem; }
+    p { font-size: 3.0rem; }
+    .units { font-size: 1.2rem; }
+    .dht-labels{
+      font-size: 1.5rem;
+      vertical-align:middle;
+      padding-bottom: 15px;
+    }
+  </style>
+</head>
+<body>
+  <h2>ESP32 DHT Server</h2>
+  <p>
+    <i class="fas fa-thermometer-half" style="color:#059e8a;"></i>
+    <span class="dht-labels">Temperature</span>
+    <span id="temperature">%TEMPERATURE%</span>
+    <sup class="units">&deg;C</sup>
+  </p>
+  <p>
+    <i class="fas fa-tint" style="color:#00add6;"></i>
+    <span class="dht-labels">Humidity</span>
+    <span id="humidity">%HUMIDITY%</span>
+    <sup class="units">&percnt;</sup>
+  </p>
+</body>
+<script>
+setInterval(function ( ) {
+  var xhttp = new XMLHttpRequest();
+  xhttp.onreadystatechange = function() {
+    if (this.readyState == 4 && this.status == 200) {
+      document.getElementById("temperature").innerHTML = this.responseText;
+    }
+  };
+  xhttp.open("GET", "/temperature", true);
+  xhttp.send();
+}, 10000 ) ;
+
+setInterval(function ( ) {
+  var xhttp = new XMLHttpRequest();
+  xhttp.onreadystatechange = function() {
+    if (this.readyState == 4 && this.status == 200) {
+      document.getElementById("humidity").innerHTML = this.responseText;
+    }
+  };
+  xhttp.open("GET", "/humidity", true);
+  xhttp.send();
+}, 10000 ) ;
+</script>
+</html>)rawliteral";
+
+// Replaces placeholder with DHT values
+String processor(const String &var)
+{
+  //Serial.println(var);
+  if (var == "TEMPERATURE") {
+    return readDHTTemperature();
+  } else if (var == "HUMIDITY") {
+    return readDHTHumidity();
+  }
+  return String();
+}
+
+void setup()
+{
+  // Serial port for debugging purposes
+  Serial.begin(115200);
+
+  // Connect to Wi-Fi
+  WiFi.begin(ssid, password);
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(1000);
+    Serial.println("Connecting to WiFi..");
+  }
+
+  // Print ESP32 Local IP Address
+  Serial.println(WiFi.localIP());
+
+  // Route for root / web page
+  server.on("/", HTTP_GET, [ ](AsyncWebServerRequest *request) {
+    request->send(200, "text/html", index_html, processor);
+  });
+  server.on("/temperature", HTTP_GET, [ ](AsyncWebServerRequest *request) {
+    request->send(200, "text/plain", readDHTTemperature().c_str());
+  });
+  server.on("/humidity", HTTP_GET, [ ](AsyncWebServerRequest *request) {
+    request->send(200, "text/plain", readDHTHumidity().c_str());
+  });
+
+  // Start server
+  server.begin();
+}
+
+void loop()
+{
+
+}

esp/cpp/05_temp-humidity-web/main/main.h

@@ -0,0 +1,33 @@
+#ifndef  MAIN_H
+#define  MAIN_H
+
+#include <cstdint>
+#include "dht.h"
+
+class DHT {
+public:
+  DHT(gpio_num_t gpio, dht_sensor_type_t type) :
+      gpio_(gpio), type_(type) { }
+
+  ~DHT() = default;
+
+  /**
+   * Read temperature from DHT sensor
+   *
+   * @param f True to return in Fahrenheit, False for Celsius.
+   */
+  float readTemperature(bool f = true);
+
+  /**
+   * Read humidity from DHT sensor.
+   */
+  float readHumidity();
+
+private:
+  gpio_num_t gpio_;
+  dht_sensor_type_t type_;
+
+};
+
+
+#endif // MAIN_H

esp/cpp/06_i2c-scanner/.gitignore

@@ -0,0 +1,4 @@
+build
+managed_components
+dependencies.lock
+sdkconfig.old

esp/cpp/06_i2c-scanner/CMakeLists.txt

@@ -0,0 +1,17 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.26)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+project(
+    #[[NAME]]   i2c-scanner
+    VERSION     0.1
+    DESCRIPTION "Simple I2C device scanner"
+    LANGUAGES   CXX
+)
+# For writing pure cmake components, see the documentation
+# https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/build-system.html#writing-pure-cmake-components
+idf_build_set_property(COMPILE_OPTIONS "-Wno-error" APPEND)

esp/cpp/06_i2c-scanner/README.md

@@ -0,0 +1,32 @@
+# 06_i2c-scanner
+
+![schematic](./schematic.png)
+
+Simple I2C device scanner.
+
+For this example I used this [SSD1306 OLED display](https://www.digikey.com/en/products/detail/winstar-display/WEA012864DWPP3N00003/20533255).
+
+To build the example run the following commands.
+
+```bash
+source ~/path/to/esp-idf/export.sh
+
+mkdir build
+cd build
+cmake ..
+make -j $(nproc)
+
+# Flash to ESP32
+make flash
+
+# Open Serial Monitor, press CTRL+] to exit.
+make monitor
+```
+
+Expected output in serial monitor at 115200 baud
+
+```bash
+Scanning I2C devices...
+[0x3c]: Device found with clock rate 100000 and timeout 50
+Done.
+```

esp/cpp/06_i2c-scanner/main/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(
+    SRCS "main.cpp"
+    INCLUDE_DIRS "."
+)

esp/cpp/06_i2c-scanner/main/idf_component.yml

@@ -0,0 +1,17 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  espressif/arduino-esp32: ^3.1.1

esp/cpp/06_i2c-scanner/main/main.cpp

@@ -0,0 +1,35 @@
+#include "Arduino.h"
+#include "Wire.h"
+
+[[maybe_unused]] static const char *TAG = "i2c-scanner";
+
+void i2c_scan()
+{
+  uint8_t device_num = 0;
+  Serial.println("Scanning I2C devices...");
+  for (byte address = 1; address < 127; address++) {
+    Wire.beginTransmission(address);
+    byte error = Wire.endTransmission();
+    if (error == 0) {
+      Serial.printf(
+          "[0x%.2x]: Device found with clock rate %lu and timeout %u\n",
+          address,
+          Wire.getClock(), Wire.getTimeOut());
+      device_num++;
+    } else if (error == 4) {
+      Serial.printf("[0x%.2x]: Unknown error.\n", address);
+    }
+  }
+  Serial.println(device_num > 0 ? "Done.\n" : "No I2C devices found.\n");
+}
+
+void setup()
+{
+  Serial.begin(115200);
+  Wire.begin();
+}
+
+void loop()
+{
+  i2c_scan();
+}

esp/cpp/07_lcd-panel-i2c/.gitignore

@@ -0,0 +1,4 @@
+build
+managed_components
+dependencies.lock
+sdkconfig.old

esp/cpp/07_lcd-panel-i2c/CMakeLists.txt

@@ -0,0 +1,17 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.26)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+project(
+    #[[NAME]]   lcd-panel-i2c
+    VERSION     0.1
+    DESCRIPTION "Using the SSD1306 LCD display with ESP-IDF and LVGL over I2C"
+    LANGUAGES   CXX
+)
+# For writing pure cmake components, see the documentation
+# https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/build-system.html#writing-pure-cmake-components
+idf_build_set_property(COMPILE_OPTIONS "-Wno-error" APPEND)

esp/cpp/07_lcd-panel-i2c/README.md

@@ -0,0 +1,29 @@
+# 07_lcd-panel-i2c
+
+Using the ESP IDF for drawing to a LCD screen over I2C.
+
+For instructions on setting up the ESP-IDF see [04_-esp-idf-arduino](./../04_esp-idf-arduino)
+
+[ESP IDF - I2C](https://docs.espressif.com/projects/esp-idf/en/v5.3.2/esp32/api-reference/peripherals/i2c.html)
+
+[ESP IDF - LCD](https://docs.espressif.com/projects/esp-idf/en/v5.3.2/esp32/api-reference/peripherals/lcd/index.html)
+
+[ESP IDF - FreeRTOS](https://docs.espressif.com/projects/esp-idf/en/v5.3.2/esp32/api-reference/system/freertos.html)
+
+![schematic](./schematic.png)
+
+Temperature and humidity sensor served on a web page within the local network.
+
+![example](./example.gif)
+
+To build this example run the following commands.
+
+```bash
+source ~/path/to/esp-idf/export.sh
+
+mkdir build
+cd build
+cmake ..
+make -j $(nproc)
+make flash
+```

esp/cpp/07_lcd-panel-i2c/main/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRC_DIRS . INCLUDE_DIRS .)

esp/cpp/07_lcd-panel-i2c/main/display.cpp

@@ -0,0 +1,176 @@
+
+#include <esp_timer.h>
+
+#include <lv_init.h>
+
+#include <mutex>
+
+#include "display.h"
+
+// TODO: Remove this dependency by relocating SSD1306::oledb_buffer_
+#include "ssd1306.h"
+
+// LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
+// We must use a mutex to protect it.
+_lock_t Display::ScopedLock::lv_lock_;
+
+// Static TimeKeeper for managing ESP timers across all displays.
+TimeKeeper Display::timers_;
+
+Display::Display(IPanelDevice &device) :
+    panel_(device),
+    lv_buf_(nullptr)
+{
+  if (!lv_is_initialized()) {
+    ESP_LOGI(TAG, "Initialize LVGL");
+    lv_init();
+  }
+
+  ESP_LOGI(TAG, "Creating LVGL display");
+  lv_display_ = panel_.device_->create_display();
+  // associate the i2c panel handle to the display
+  lv_display_set_user_data(lv_display_, panel_.esp_panel_);
+
+  register_draw_buffer();
+  register_lvgl_tick_timer();
+
+  ESP_LOGI(TAG, "Create LVGL FreeRTOS task");
+  xTaskCreate(Display::lvgl_port_task, "LVGL", LVGL_TASK_STACK_SIZE,
+              nullptr, LVGL_TASK_PRIORITY, nullptr);
+}
+
+void Display::set_text(const char *text,
+                       const char *name,
+                       lv_label_long_mode_t long_mode,
+                       lv_align_t align)
+{
+  // Lock the mutex due to the LVGL APIs are not thread-safe.
+  ScopedLock lock;
+
+  ESP_LOGI(TAG, "Display LVGL Scroll Text");
+  lv_obj_t *scr = lv_display_get_screen_active(lv_display_);
+
+  // Create the label if it's `name` doesn't already exist in the map keys.
+  if (!lv_objects_.count(name)) {
+    lv_objects_[name] = lv_label_create(scr);
+  }
+  auto obj = lv_objects_[name];
+
+  // Circular scroll.
+  lv_label_set_long_mode(obj, long_mode);
+  lv_label_set_text(obj, text);
+
+  // Set the size of the screen.
+  // If you use rotation 90 or 270 use lv_display_get_vertical_resolution.
+  lv_obj_set_width(obj, lv_display_get_horizontal_resolution(lv_display_));
+  lv_obj_align(obj, align, 0, 0);
+}
+
+bool Display::lvgl_flush_ready_cb(esp_lcd_panel_io_handle_t,
+                                  esp_lcd_panel_io_event_data_t *,
+                                  void *user_ctx)
+{
+  auto *disp = (lv_display_t *) user_ctx;
+  lv_display_flush_ready(disp);
+  return false;
+}
+
+void Display::lvgl_flush_cb(lv_display_t *display, const lv_area_t *area,
+                            uint8_t *px_map) // NOLINT(*-non-const-parameter)
+{
+  auto panel_handle =
+      (esp_lcd_panel_handle_t) lv_display_get_user_data(display);
+
+  // Necessary because LVGL reserves 2x4 bytes in the buffer for a palette.
+  // For more information about the monochrome, please refer to:
+  // https://docs.lvgl.io/9.2/porting/display.html#monochrome-displays
+  // Skip the palette here.
+  px_map += LVGL_PALETTE_SIZE;
+
+  uint16_t hor_res = lv_display_get_physical_horizontal_resolution(display);
+  int32_t x1 = area->x1;
+  int32_t x2 = area->x2;
+  int32_t y1 = area->y1;
+  int32_t y2 = area->y2;
+
+  for (int32_t y = y1; y <= y2; y++) {
+    for (int32_t x = x1; x <= x2; x++) {
+      /* The order of bits is MSB first.
+                  MSB           LSB
+         bits      7 6 5 4 3 2 1 0
+         pixels    0 1 2 3 4 5 6 7
+                  Left         Right
+      */
+      bool chroma_color = (px_map[(hor_res >> 3) * y + (x >> 3)] &
+                           1 << (7 - x % 8));
+
+      // Write to the buffer as required for the display.
+      // It writes only 1-bit for monochrome displays mapped vertically.
+      uint8_t *buf = SSD1306::oled_buffer_ + hor_res * (y >> 3) + (x);
+      if (chroma_color) {
+        (*buf) &= ~(1 << (y % 8));
+      } else {
+        (*buf) |= (1 << (y % 8));
+      }
+    }
+  }
+  // Pass the draw buffer to the driver.
+  ESP_ERROR_CHECK(
+      esp_lcd_panel_draw_bitmap(panel_handle, x1, y1, x2 + 1, y2 + 1,
+                                SSD1306::oled_buffer_));
+}
+
+void Display::lvgl_increase_tick_cb(void *)
+{
+  // Tell LVGL how many milliseconds has elapsed
+  lv_tick_inc(LVGL_TICK_PERIOD_MS);
+}
+
+[[noreturn]] void Display::lvgl_port_task(void *)
+{
+  ESP_LOGI(TAG, "Starting LVGL task");
+  for (uint32_t time_till_next_ms = 0; true;) {
+    _lock_acquire(&ScopedLock::lv_lock_);
+    time_till_next_ms = lv_timer_handler();
+    _lock_release(&ScopedLock::lv_lock_);
+    usleep(1000 * time_till_next_ms);
+  }
+}
+
+void Display::register_draw_buffer()
+{
+  // Create draw buffer.
+  ESP_LOGI(TAG, "Allocate separate LVGL draw buffers");
+  lv_buf_ = heap_caps_calloc(1, panel_.device_->lv_buf_size_,
+                             MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
+  assert(lv_buf_);
+
+  ESP_LOGI(TAG, "Set LVGL draw buffers");
+  // Color format must be set first, LVGL9 suooprt new monochromatic format.
+  lv_display_set_color_format(lv_display_, LV_COLOR_FORMAT_I1);
+  lv_display_set_buffers(lv_display_, lv_buf_, nullptr,
+                         panel_.device_->lv_buf_size_,
+                         LV_DISPLAY_RENDER_MODE_FULL);
+  lv_display_set_rotation(lv_display_, LV_DISPLAY_ROTATION_0);
+
+  ESP_LOGI(TAG, "Set LVGL callback for flushing to the display");
+  lv_display_set_flush_cb(lv_display_, Display::lvgl_flush_cb);
+
+  ESP_LOGI(TAG, "Register io panel callback for LVGL flush ready notification");
+  const esp_lcd_panel_io_callbacks_t cbs = {
+      .on_color_trans_done = Display::lvgl_flush_ready_cb,
+  };
+  ESP_ERROR_CHECK(
+      esp_lcd_panel_io_register_event_callbacks(panel_.esp_io_, &cbs,
+                                                lv_display_));
+}
+
+void Display::register_lvgl_tick_timer()
+{
+  ESP_LOGI(TAG, "Use esp_timer to increase LVGL tick");
+  const esp_timer_create_args_t esp_timer_args = {
+      .callback = &Display::lvgl_increase_tick_cb,
+      .name = "lvgl_tick"
+  };
+  timers_.start_new_timer_periodic(esp_timer_args, LVGL_TICK_PERIOD_MS * 1000);
+}

esp/cpp/07_lcd-panel-i2c/main/display.h

@@ -0,0 +1,139 @@
+#ifndef DISPLAY_H
+#define DISPLAY_H
+
+
+#include <widgets/label/lv_label.h>
+
+#include <unordered_map>
+
+#include "time_keeper.h"
+#include "panel.h"
+
+#define LVGL_TICK_PERIOD_MS    5
+#define LVGL_TASK_STACK_SIZE   (4 * 1024)
+#define LVGL_TASK_PRIORITY     2
+
+class Display {
+public:
+  //
+  // CONSTRUCTORS
+
+  Display(const Display &) = delete;
+
+  Display(Display &) = delete;
+
+  Display &operator=(Display &) = delete;
+
+  /**
+   * Construct a new Display using an IPanelDevice.
+   *
+   * @param device An object that implements the IPanelDevice interface.
+   */
+  explicit Display(IPanelDevice &device);
+
+  ~Display() = default;
+
+  //
+  // GETTERS
+
+  /**
+   * Getter for accessing LVGL display handle.
+   *
+   * @sa ScopedLock for calling custom LVGL API's not implemented by Display.
+   */
+  [[nodiscard]] inline const lv_display_t *get() const { return lv_display_; }
+
+  /**
+   * Getter for accessing LVGL display handle.
+   *
+   * @sa ScopedLock for calling custom LVGL API's not implemented by Display.
+   */
+  [[nodiscard]] inline lv_display_t *get() { return lv_display_; }
+
+  /// Dereference operator for accessing LVGL display handle.
+  [[nodiscard]] inline const lv_display_t *operator*() const { return get(); }
+
+  /// Dereference operator for accessing LVGL display handle.
+  [[nodiscard]] inline lv_display_t *operator*() { return get(); }
+
+  //
+  // LVGL OPERATIONS
+
+  /**
+   * Create a LVGL label with some given text on the current display.
+   * The name of the object can be reused to change text on this label later.
+   *
+   * @param text Text to write to the display.
+   * @param name Name for the LVGL label object associated with this text.
+   * @param long_mode LVGL long mode for text wider than the current display.
+   * @param align LVGL alignment to use for placing the label on the display.
+   */
+  void set_text(const char *text,
+                const char *name,
+                lv_label_long_mode_t long_mode = LV_LABEL_LONG_SCROLL_CIRCULAR,
+                lv_align_t align = LV_ALIGN_TOP_MID);
+
+  //
+  // TYPE DEFINITIONS
+
+  /**
+   * Obtains LVGL API mutex lock for the duration of local scope.
+   *
+   * LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
+   */
+  struct ScopedLock {
+    explicit ScopedLock() { _lock_acquire(&lv_lock_); }
+
+    ~ScopedLock() { _lock_release(&lv_lock_); }
+
+    /// Mutex used to protect LVGL API calls.
+    static _lock_t lv_lock_;
+  };
+
+  //
+  // PUBLIC STATIC MEMBERS
+
+  /// Public static TimeKeeper for managing ESP timers across all displays.
+  static TimeKeeper timers_;
+
+private:
+  /// Registers LVGL draw buffers for this display.
+  void register_draw_buffer();
+
+  /// Registers LVGL ticker timer callback for rendering this display.
+  static void register_lvgl_tick_timer();
+
+  static bool lvgl_flush_ready_cb(esp_lcd_panel_io_handle_t panel,
+                                  esp_lcd_panel_io_event_data_t *data,
+                                  void *user_ctx);
+
+  static void lvgl_flush_cb(lv_display_t *display,
+                            const lv_area_t *area,
+                            uint8_t *px_map);
+
+  static void lvgl_increase_tick_cb(void *arg);
+
+  [[noreturn]] static void lvgl_port_task(void *arg);
+
+  //
+  // PRIVATE MEMBERS
+
+  /// Panel associated with this Display.
+  Panel panel_;
+
+  /// LVGL display handle.
+  lv_display_t *lv_display_;
+
+  /// LVGL draw buffer associated with this Display's lv_display_t.
+  void *lv_buf_;
+
+  /**
+   * LVGL object handles stored in the LVGL screen associated with this Display.
+   *
+   * @sa Display::set_text
+   * @sa lv_display_get_screen_active
+   */
+  std::unordered_map<const char *, lv_obj_t *> lv_objects_;
+};
+
+#endif // DISPLAY_H

esp/cpp/07_lcd-panel-i2c/main/i2c.h

@@ -0,0 +1,42 @@
+#ifndef I2C_H
+#define I2C_H
+
+#define I2C_BUS_PORT  0
+
+#include <driver/i2c_master.h>
+
+static const char *TAG = "lcd-panel";
+
+struct I2C {
+  I2C(gpio_num_t sda, gpio_num_t scl, int rst = -1) :
+      esp_i2c_bus_(nullptr),
+      rst_num_(rst),
+      esp_bus_config_(
+          (i2c_master_bus_config_t) {
+              .i2c_port = I2C_BUS_PORT,
+              .sda_io_num = sda,
+              .scl_io_num = scl,
+              .clk_source = I2C_CLK_SRC_DEFAULT,
+              .glitch_ignore_cnt = 7,
+              .flags {
+                  .enable_internal_pullup = true,
+              },
+          }
+      )
+  {
+    ESP_LOGI(TAG, "Initializing new master I2C bus");
+    ESP_ERROR_CHECK(i2c_new_master_bus(&esp_bus_config_, &esp_i2c_bus_));
+  }
+
+  ~I2C() = default;
+
+  // TODO: Can you use the I2C get_master_bus API in a static method?
+  i2c_master_bus_handle_t esp_i2c_bus_;
+
+  int rst_num_;
+
+private:
+  i2c_master_bus_config_t esp_bus_config_;
+};
+
+#endif //I2C_H

esp/cpp/07_lcd-panel-i2c/main/idf_component.yml

@@ -0,0 +1,5 @@
+## IDF Component Manager Manifest File
+dependencies:
+  espressif/arduino-esp32: ^3.1.1
+  lvgl/lvgl: "9.2.0"
+  esp_lcd_sh1107: "^1"

esp/cpp/07_lcd-panel-i2c/main/main.cpp

@@ -0,0 +1,34 @@
+#include "display.h"
+#include "ssd1306.h"
+
+// Pin may vary based on your schematic.
+#define PIN_SDA                GPIO_NUM_21
+#define PIN_SCL                GPIO_NUM_22
+#define PIN_RST                (-1)
+
+I2C i2c(PIN_SDA, PIN_SCL, PIN_RST);
+
+void setup()
+{
+  SSD1306 ssd1306(i2c);
+  Display d(ssd1306);
+
+  d.set_text("Test test 12345678910",
+             "test-text1",
+             LV_LABEL_LONG_SCROLL,
+             LV_ALIGN_CENTER);
+
+  d.set_text("Test test changing text",
+             "test-text1",
+             LV_LABEL_LONG_SCROLL,
+             LV_ALIGN_CENTER);
+
+  d.set_text("Hello hello hello hello hello hello hello hello!", "test-text2");
+
+  d.set_text("A random sentence with no meaning at all.",
+             "test-text3",
+             LV_LABEL_LONG_CLIP,
+             LV_ALIGN_BOTTOM_MID);
+}
+
+void loop() { }

esp/cpp/07_lcd-panel-i2c/main/panel.h

@@ -0,0 +1,44 @@
+#ifndef PANEL_H
+#define PANEL_H
+
+#include "panel_device.h"
+
+class Panel {
+public:
+  explicit Panel(IPanelDevice &device) :
+      device_(&device),
+      esp_io_(nullptr),
+      esp_panel_(nullptr),
+      esp_panel_config_(
+          (esp_lcd_panel_dev_config_t) {
+              .reset_gpio_num = device_->rst_num_,
+              .bits_per_pixel = 1,
+              .vendor_config = device_->vendor_config(),
+          }
+      )
+  {
+    esp_io_ = device_->create_io_handle();
+
+    device_->create_panel(esp_panel_config_, esp_io_, esp_panel_);
+
+    ESP_LOGI(TAG, "Resetting panel display");
+    ESP_ERROR_CHECK(esp_lcd_panel_reset(esp_panel_));
+    ESP_LOGI(TAG, "Initializing panel display");
+    ESP_ERROR_CHECK(esp_lcd_panel_init(esp_panel_));
+    ESP_LOGI(TAG, "Turning on panel display");
+    ESP_ERROR_CHECK(esp_lcd_panel_disp_on_off(esp_panel_, true));
+  }
+
+  ~Panel() = default;
+
+  IPanelDevice *device_;
+
+  esp_lcd_panel_io_handle_t esp_io_;
+
+  esp_lcd_panel_handle_t esp_panel_;
+
+private:
+  esp_lcd_panel_dev_config_t esp_panel_config_;
+};
+
+#endif //PANEL_H

esp/cpp/07_lcd-panel-i2c/main/panel_device.h

@@ -0,0 +1,89 @@
+#ifndef PANEL_DEVICE_H
+#define PANEL_DEVICE_H
+
+#include <esp_lcd_panel_dev.h>
+#include <esp_lcd_panel_ops.h>
+#include <esp_lcd_panel_io.h>
+#include <esp_log.h>
+
+#include <display/lv_display.h>
+
+#include "i2c.h"
+
+#define LVGL_PALETTE_SIZE      8
+
+class IPanelDevice {
+public:
+  explicit IPanelDevice(I2C &i2c,
+                        esp_lcd_panel_io_i2c_config_t config,
+                        int width,
+                        int height) :
+      IPanelDevice(i2c, config, width, height,
+                   width * height / 8 + LVGL_PALETTE_SIZE) { }
+
+  explicit IPanelDevice(I2C &i2c,
+                        esp_lcd_panel_io_i2c_config_t io_config,
+                        int width,
+                        int height,
+                        size_t draw_buf_size) :
+      width_(width),
+      height_(height),
+      rst_num_(i2c.rst_num_),
+      lv_buf_size_(draw_buf_size),
+      esp_i2c_bus_(i2c.esp_i2c_bus_),
+      esp_io_config_(io_config) { }
+
+  virtual ~IPanelDevice() = default;
+
+  [[nodiscard]] lv_display_t *create_display() const
+  {
+    auto display = lv_display_create(width_, height_);
+    assert(display);
+    return display;
+  }
+
+  [[nodiscard]] esp_lcd_panel_io_handle_t create_io_handle()
+  {
+    ESP_LOGI(TAG, "Creating panel IO handle");
+    esp_lcd_panel_io_handle_t handle = nullptr;
+    ESP_ERROR_CHECK(
+        esp_lcd_new_panel_io_i2c(esp_i2c_bus_, &esp_io_config_, &handle));
+    return handle;
+  }
+
+  void create_panel(esp_lcd_panel_dev_config_t &config,
+                    esp_lcd_panel_io_handle_t io,
+                    esp_lcd_panel_handle_t &panel)
+  {
+    // If the passed handle is already allocated, delete it.
+    if (panel != nullptr) {
+      ESP_LOGI(TAG, "Removing unused panel");
+      esp_lcd_panel_del(panel);
+    }
+
+    ESP_LOGI(TAG, "Install SSD1306 panel driver");
+    init_panel(config, io, panel);
+  }
+
+  virtual void *vendor_config() = 0;
+
+  int32_t width_;
+
+  int32_t height_;
+
+  int rst_num_;
+
+  // LVGL reserves 2x4 bytes in the buffer to be used as a palette.
+  size_t lv_buf_size_;
+
+  i2c_master_bus_handle_t esp_i2c_bus_;
+
+  esp_lcd_panel_io_i2c_config_t esp_io_config_;
+
+private:
+  virtual void init_panel(esp_lcd_panel_dev_config_t &config,
+                          esp_lcd_panel_io_handle_t io,
+                          esp_lcd_panel_handle_t &panel) = 0;
+};
+
+#endif // PANEL_DEVICE_H

esp/cpp/07_lcd-panel-i2c/main/ssd1306.cpp

@@ -0,0 +1,6 @@
+
+#include "ssd1306.h"
+
+// To use LV_COLOR_FORMAT_I1 we need an extra buffer to hold the converted data.
+// TODO: Remove this and SSD1306 can be header only.
+uint8_t SSD1306::oled_buffer_[LCD_H_RES * LCD_V_RES / 8];

esp/cpp/07_lcd-panel-i2c/main/ssd1306.h

@@ -0,0 +1,83 @@
+/*
+ * https://docs.espressif.com/projects/esp-idf/en/v5.3.2/esp32/api-reference/peripherals/lcd/index.html#functional-overview
+ *
+ * Implementing the interface draw to an LCD using various interface modes.
+ * I2C interface mode is SSD1306
+ * SPI interface mode is ST7789
+ * I80 interface mode is NT35510 or ST7789
+ *
+ * Actually, I think any driver can be used with any interface mode
+ * Along with additional third party drivers via the component manager
+ * https://github.com/espressif/esp-idf/tree/0d6099ec533c4b647fb7a7b0b8942bc7aeb82f90/examples/peripherals/lcd/spi_lcd_touch#spi-lcd-and-touch-panel-example
+ */
+
+#ifndef SSD1306_H
+#define SSD1306_H
+
+#include <esp_lcd_panel_ssd1306.h>
+
+#include "panel_device.h"
+
+// According to specific display hardware.
+// https://www.digikey.com/en/products/detail/winstar-display/WEA012864DWPP3N00003/20533255
+#define SCREEN_WIDTH           128  // OLED display width, in pixels.
+#define SCREEN_HEIGHT          64  // OLED display height, in pixels.
+
+// According to SSD1306 datasheet.
+// https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
+#define LCD_H_RES              128
+#define LCD_V_RES              64
+#define I2C_HW_ADDR            0x3C
+#define LCD_PIXEL_CLOCK_HZ     (400 * 1000)
+// Bit number used to represent command and parameter
+#define LCD_CMD_BITS           8
+#define LCD_PARAM_BITS         8
+
+class SSD1306 final : public IPanelDevice {
+public:
+  // Constructors allow overriding ssd1306 config.
+  explicit SSD1306(I2C &i2c) :
+      SSD1306(i2c, {.height = SCREEN_HEIGHT}) { }
+
+  SSD1306(I2C &i2c,
+          esp_lcd_panel_ssd1306_config_t config,
+          int width = SCREEN_WIDTH,
+          int height = SCREEN_HEIGHT
+  ) :
+      IPanelDevice(i2c,
+                   (esp_lcd_panel_io_i2c_config_t) {
+                       .dev_addr = I2C_HW_ADDR,
+                       .control_phase_bytes = 1,
+                       .dc_bit_offset = 6,
+                       .lcd_cmd_bits = LCD_CMD_BITS,
+                       .lcd_param_bits = LCD_PARAM_BITS,
+                       .scl_speed_hz = LCD_PIXEL_CLOCK_HZ,
+                   },
+                   width,
+                   height
+      ),
+      ssd1306_config_(config) { }
+
+  ~SSD1306() final = default;
+
+  void *vendor_config() override
+  {
+    return &ssd1306_config_;
+  }
+
+  // The configuration structure specific to the SSD1306.
+  esp_lcd_panel_ssd1306_config_t ssd1306_config_;
+
+  // For LV_COLOR_FORMAT_I1 we need an extra buffer to hold the converted data.
+  static uint8_t oled_buffer_[LCD_H_RES * LCD_V_RES / 8];
+
+private:
+  void init_panel(esp_lcd_panel_dev_config_t &config,
+                  esp_lcd_panel_io_handle_t io,
+                  esp_lcd_panel_handle_t &panel) override
+  {
+    ESP_ERROR_CHECK(esp_lcd_new_panel_ssd1306(io, &config, &panel));
+  }
+};
+
+#endif // SSD1306_H

esp/cpp/07_lcd-panel-i2c/main/time_keeper.h

@@ -0,0 +1,131 @@
+
+#ifndef TIME_KEEPER_H
+#define TIME_KEEPER_H
+
+#include <esp_log.h>
+#include <esp_timer.h>
+
+#include "i2c.h"
+
+/**
+ * Stores arguments and ESP timer handle for a Timer.
+ * In general Timers should be used via the TimeKeeper interface only.
+ *
+ * Timers cannot be copied, and are only created by a TimeKeeper instance.
+ * The public way to access a Timer is by obtaining a TimerHandle (Timer *).
+ * The TimeKeeper can delete existing Timers, calling it's destructor.
+ * The ESP timer will be deleted when this class desctructor is called.
+ */
+struct Timer {
+  Timer(const Timer &) = delete;
+
+  Timer(Timer &) = delete;
+
+  Timer &operator=(Timer &) = delete;
+
+  explicit Timer(esp_timer_create_args_t args) :
+      args_(args), esp_timer_(nullptr)
+  {
+    ESP_LOGI(TAG, "Creating esp_timer with name: %s", args_.name);
+    ESP_ERROR_CHECK(esp_timer_create(&args, &esp_timer_));
+  }
+
+  ~Timer()
+  {
+    ESP_LOGI(TAG, "Destroying esp_timer with name: %s", args_.name);
+    ESP_ERROR_CHECK(esp_timer_delete(esp_timer_));
+  }
+
+  /// Arguments passed to ESP API during timer creation.
+  esp_timer_create_args_t args_;
+
+  /// ESP timer handle.
+  esp_timer_handle_t esp_timer_;
+};
+
+/**
+ * ESP timer mananger class.
+ *
+ * Timers should only be accessed using the get_handle method.
+ * If the Timer destructor is called the underlying ESP timer will be deleted.
+ */
+struct TimeKeeper {
+  /// Timer handle type used for referring to Timers.
+  using TimerHandle = Timer *;
+
+  TimerHandle get_handle(const char *name)
+  {
+    return &managed_timers_.at(name);
+  }
+
+  TimerHandle operator[](const char *name) { return get_handle(name); }
+
+  /**
+   * Create a new managed Timer with the provided ESP arguments.
+   * The timer can be retrieved later using the args.name field value.
+   *
+   * @param args ESP timer creation arguments.
+   * @return TimerHandle Handle to a Timer managed by this TimeKeeper.
+   * @sa get_handle
+   * @sa operator[](const char*)
+   */
+  TimerHandle create_timer(esp_timer_create_args_t args)
+  {
+    auto rt = managed_timers_.emplace(args.name, args);
+    if (!rt.second) {
+      ESP_LOGE(TAG, "Display::Timer already exists with name %s", args.name);
+      return nullptr;
+    }
+    return &rt.first->second;
+  }
+
+  /// Stop a Timer with the given name.
+  [[maybe_unused]] void stop_timer(const char *name)
+  {
+    ESP_ERROR_CHECK(esp_timer_stop(get_handle(name)->esp_timer_));
+  }
+
+  /// Delete a Timer with the given name.
+  [[maybe_unused]] void delete_timer(const char *name)
+  {
+    managed_timers_.erase(name);
+  }
+
+  /// Create a Timer with the ESP args and call esp_timer_start_periodic.
+  [[maybe_unused]] void
+  start_new_timer_periodic(esp_timer_create_args_t args,
+                           uint64_t period)
+  {
+    start_timer_periodic(create_timer(args)->args_.name, period);
+  }
+
+  /// Calls esp_timer_start_periodic on the Timer with the given name.
+  [[maybe_unused]] void start_timer_periodic(const char *name,
+                                             uint64_t period)
+  {
+    ESP_ERROR_CHECK(
+        esp_timer_start_periodic(get_handle(name)->esp_timer_, period));
+  }
+
+  /// Create a Timer with the ESP args and call esp_timer_start_once.
+  [[maybe_unused]] void
+  start_new_timer_once(esp_timer_create_args_t args,
+                       uint64_t timeout_us)
+  {
+    start_timer_once(create_timer(args)->args_.name, timeout_us);
+  }
+
+  /// Calls esp_timer_start_once on the Timer with the given name.
+  [[maybe_unused]] void start_timer_once(const char *name,
+                                         uint64_t timeout_us)
+  {
+    ESP_ERROR_CHECK(
+        esp_timer_start_once(get_handle(name)->esp_timer_, timeout_us));
+  }
+
+private:
+  /// Existing ESP timers created for this TimeKeeper instance.
+  std::unordered_map<const char *, Timer> managed_timers_;
+};
+
+#endif // TIME_KEEPER_H

esp/cpp/README.md

@@ -5,18 +5,17 @@ shaunrd0/klips/esp/
 ├── 01_led-button               # Simple LED circuit controlled by an on board button.
 ├── 02_led-button-web           # LED controlled by a button or within a web browser.
 ├── 03_temp-humidity-web        # Temperature and humidity sensor within a web browser.
+├── 04_esp-idf-arduino          # CMake example instead of Arduino IDE for ESP development.
+├── 05_temp-humidity-web        # Temperature and humidity sensor within a web browser.
+├── 06_i2c-scanner              # Simple I2C device scanner.
 ├── ESP32-basic-starter-kit.pdf # PDF for tutorials in ESP32 starter kit.
 ├── ESP32-dev-module.png
 └── README.md
 ```
 
-This directory contains ESP32 projects largely adapted from the examples in [ESP32-basic-starter-kit.pdf](./ESP32-basic-starter-kit.pdf).
+Examples 1-3 are built using the Arduino IDE.
 
-The APIs in the original examples paired with this PDF have changed, and I decided to do some different things with the code and/or circuits, but the original code can be [found here](https://www.dropbox.com/scl/fo/6znlij3eb23ih4jxcpv2w/AKvB1t9CCUgoVRVtGen8Yrw?rlkey=z84anl0hs940qf9fpl7l8q8q2&e=1&dl=0).
-
-The board selected in [Arduino IDE](https://www.arduino.cc/en/software) is ESP32 Dev Module -
-
-![ESP32 Dev Module](./ESP32-dev-module.png)
+All examples after `04_esp-idf-arduino` are built with cmake and the [ESP-IDF](https://github.com/espressif/esp-idf).
 
 [Arduino ESP32 GitHub](https://github.com/espressif/arduino-esp32) \
 [Arduino ESP32 API reference](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html)