[esp] Port temp-humidity-web example to cmake.

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/README.md

@@ -6,6 +6,7 @@ shaunrd0/klips/esp/
 ├── 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.
 ├── ESP32-basic-starter-kit.pdf # PDF for tutorials in ESP32 starter kit.
 ├── ESP32-dev-module.png
 └── README.md