[esp] Add temperature and humidity example.

2025-02-01 14:34:07 -05:00 · 2025-02-01 14:34:07 -05:00 · e6ba60da89
commit e6ba60da89
parent 8bf174d256
5 changed files with 218 additions and 0 deletions
--- a/esp/cpp/03_temp-humidity-web/03_temp-humidity-web.ino
+++ b/esp/cpp/03_temp-humidity-web/03_temp-humidity-web.ino
@ -0,0 +1,161 @@
+// Import required libraries
+
+#include "WiFi.h"
+#include "ESPAsyncWebServer.h"
+#include <Adafruit_Sensor.h>
+#include <DHT.h>
+
+// Replace with your network credentials
+const char* ssid = "network-name";
+const char* password = "password";
+
+#define DHTPIN 4     // Digital pin connected to the DHT sensor
+
+// Uncomment the type of sensor in use:
+#define DHTTYPE    DHT11     // DHT 11
+//#define DHTTYPE    DHT22     // DHT 22 (AM2302)
+//#define DHTTYPE    DHT21     // DHT 21 (AM2301)
+
+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)
+  // Read temperature as Celsius (the default)
+  float t = dht.readTemperature();
+  // Read temperature as Fahrenheit (isFahrenheit = true)
+  //float t = dht.readTemperature(true);
+  // 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);
+
+  dht.begin();
+
+  // 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_P(200, "text/html", index_html, processor);
+  });
+  server.on("/temperature", HTTP_GET, [](AsyncWebServerRequest *request){
+    request->send_P(200, "text/plain", readDHTTemperature().c_str());
+  });
+  server.on("/humidity", HTTP_GET, [](AsyncWebServerRequest *request){
+    request->send_P(200, "text/plain", readDHTHumidity().c_str());
+  });
+
+  // Start server
+  server.begin();
+}
+
+void loop(){
+
+}
--- a/esp/cpp/03_temp-humidity-web/README.md
+++ b/esp/cpp/03_temp-humidity-web/README.md
@ -0,0 +1,56 @@
+# 03_temp-humidity-web
+
+![schematic](./schematic.png)
+
+Temperature and humidity sensor served on a web page within the local network.
+
+![screenshot](./screenshot.png)
+
+## Dependencies
+
+You need to install a couple of libraries for this project:
+
+* The DHT and the Adafruit Unified Sensor Driver libraries to read from the DHT sensor.
+* ESPAsyncWebServer and Async TCP libraries to build the asynchronous web server.
+
+The default Arduino IDE installation will store libraries at `~/Arduino/ibraries` - if this directory doesn't exist, create it.
+
+### Installing DHT Sensor Library
+
+To read from the DHT sensor using Arduino IDE, you need to install the [DHT sensor library](https://github.com/adafruit/DHT-sensor-library).
+
+```bash
+wget -O DHT_sensor.zip https://github.com/adafruit/DHT-sensor-library/archive/master.zip
+unzip DHT_sensor.zip
+mv DHT-sensor-library-master/ ~/Arduino/libraries/DHT_sensor
+```
+
+## Install Adafruit Unified Sensor Driver Library
+
+You also need to install the [Adafruit Unified Sensor Driver library](https://github.com/adafruit/Adafruit_Sensor) to work with the DHT sensor.
+
+```bash
+wget -O Adafruit_sensor.zip https://github.com/adafruit/Adafruit_Sensor/archive/master.zip
+unzip Adafruit_sensor.zip
+mv Adafruit_Sensor-master/ ~/Arduino/libraries/Adafruit_sensor
+```
+
+## Installing ESPAsyncWebServer Library
+
+Follow the next steps to install the [ESPAsyncWebServer library](https://github.com/me-no-dev/ESPAsyncWebServer):
+
+```bash
+wget -O ESPAsyncWebServer.zip https://github.com/me-no-dev/ESPAsyncWebServer/archive/master.zip
+unzip ESPAsyncWebServer.zip
+mv ESPAsyncWebServer-master/ ~/Arduino/libraries/ESPAsyncWebServer
+```
+
+## Installing Async TCP Library
+
+The ESPAsyncWebServer library requires the [AsyncTCP library](https://github.com/me-no-dev/AsyncTCP) to work. Follow the next steps to install that library:
+
+```bash
+wget -O AsyncTCP.zip https://github.com/me-no-dev/AsyncTCP/archive/master.zip
+unzip AsyncTCP.zip
+mv AsyncTCP-master/ ~/Arduino/libraries/AsyncTCP
+```
--- a/esp/cpp/03_temp-humidity-web/schematic.png
+++ b/esp/cpp/03_temp-humidity-web/schematic.png
--- a/esp/cpp/03_temp-humidity-web/screenshot.png
+++ b/esp/cpp/03_temp-humidity-web/screenshot.png
--- a/esp/cpp/README.md
+++ b/esp/cpp/README.md
@ -4,6 +4,7 @@
 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.
 ├── ESP32-basic-starter-kit.pdf # PDF for tutorials in ESP32 starter kit.
 ├── ESP32-dev-module.png
 └── README.md