Examples as Arduino sketches: one folder per device type, each its own endpointId, Wi-Fi with a timeout

Light, DimmableLight, ColorTemperatureLight, ColorLight, TemperatureSensor, ContactSensor, Blind,
Thermostat, Lock, Scene, Doorbell and MultiDevice on the 2.0 API: addCapability(row, instance), one
onDirective() handler, the report helpers, ChangeReports from loop(), a deferred answer for the lock.
Wi-Fi is waited for 30 s, then the sketch says what to check and carries on.

examples/README.md has what each sketch does, its limits and the measured sizes for d1_mini: Light
takes 30,616 bytes of static RAM and 332,565 of flash; all 17 sketches build with 0 warnings.
test/test_examples compares the discovery object of every new sketch: 147 host tests (were 135).
The sketches were compiled, not run on a board.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

examples/ContactSensor/ContactSensor.ino

@@ -0,0 +1,105 @@
+// ContactSensor: a door or window contact that tells Alexa when it opens and closes (Alexa.ContactSensor).
+//
+// A reed switch connects the pin to ground while the door is closed; the internal pull-up makes the pin high when
+// it opens. A level has to hold for 50 ms before it counts. Every change is sent as a ChangeReport; ReportState
+// is answered with the state of the contact. A change while there is no session with the broker is not reported
+// later: Alexa gets the state with its next ReportState.
+#include <Arduino.h>
+#include <ESP8266WiFi.h>
+#include <Alex2ESP.h>
+
+// Wi-Fi and the credentials of your Alex2MQTT account
+const char *WIFI_SSID = "";
+const char *WIFI_PASSWORD = "";
+
+const char *ALEXA_USERNAME = "";
+const char *ALEXA_PASSWORD = "";
+const char *ALEXA_ROOT_TOPIC = "";
+
+const uint8_t CONTACT_PIN = 14; // D5 on a Wemos D1 mini
+const unsigned long DEBOUNCE_MS = 50;
+
+Alex2ESP alexa;
+AlexaDevice *contact;
+
+bool isOpen = false;
+bool lastLevel = false;
+unsigned long lastEdge = 0;
+
+// Joins the Wi-Fi network and returns after 30 s at the latest. Without a connection the sketch carries on: the
+// ESP8266 keeps trying, and alexa.loop() opens the MQTT session once Wi-Fi is up.
+void connectWiFi()
+{
+  WiFi.mode(WIFI_STA);
+  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
+  Serial.printf("\n[WIFI] Connecting to \"%s\"\n", WIFI_SSID);
+
+  unsigned long started = millis();
+  while (WiFi.status() != WL_CONNECTED && millis() - started < 30000)
+  {
+    delay(100);
+  }
+
+  if (WiFi.status() == WL_CONNECTED)
+  {
+    Serial.printf("[WIFI] Connected, IP address %s\n", WiFi.localIP().toString().c_str());
+  }
+  else
+  {
+    Serial.printf("[WIFI] No connection after 30 s (status %d): check WIFI_SSID and WIFI_PASSWORD. Still trying.\n",
+                  WiFi.status());
+  }
+}
+
+void onDirective(AlexaDirective &directive)
+{
+  if (directive.isReportState())
+  {
+    directive.stateReport().addHealthProp(EndpointHealth::OK).addContactSensorProp(isOpen).send();
+    return;
+  }
+
+  directive.error(AlexaErrorType::INVALID_DIRECTIVE, "A contact takes no directives").send();
+}
+
+void setup()
+{
+  Serial.begin(74880);
+  pinMode(CONTACT_PIN, INPUT_PULLUP);
+  isOpen = lastLevel = digitalRead(CONTACT_PIN) == HIGH;
+
+  connectWiFi();
+
+  // MQTT user name, MQTT password, root topic
+  alexa.begin(ALEXA_USERNAME, ALEXA_PASSWORD, ALEXA_ROOT_TOPIC);
+
+  // The name Alexa shows, and the id of the endpoint: every device of an account has its own
+  contact = alexa.getDevice("Back Door", "esp-contact");
+  contact->setDisplayCategory(DisplayCategory::CONTACT_SENSOR);
+  contact->addCapability(AlexaInterfaces::ContactSensor)->setProactivelyReported(true);
+  contact->addCapability(AlexaInterfaces::EndpointHealth);
+  contact->onDirective(onDirective);
+}
+
+void loop()
+{
+  alexa.loop();
+
+  bool level = digitalRead(CONTACT_PIN) == HIGH;
+  if (level != lastLevel)
+  {
+    lastLevel = level;
+    lastEdge = millis();
+  }
+
+  if (level != isOpen && millis() - lastEdge >= DEBOUNCE_MS)
+  {
+    isOpen = level;
+    Serial.println(isOpen ? "[CONTACT] open" : "[CONTACT] closed");
+    contact->changeReport(AlexaCause::PHYSICAL_INTERACTION)
+        .addContactSensorProp(isOpen)
+        .context()
+        .addHealthProp(EndpointHealth::OK)
+        .send();
+  }
+}