MMWAVE

#include <WiFi.h>
#include <PubSubClient.h>

/* ========= CONFIG ========= */

// WLAN
const char* ssid     = "SSID";
const char* password = "PASSWORD";

// MQTT
const char* mqtt_server = "192.168.1.110";
const int   mqtt_port   = 1883;

// MQTT Login
const char* mqtt_user = "mqtt-user";
const char* mqtt_pass = "mqtt-user";

// MQTT Topics
const char* topic_presence = "home/mmwave/presence";
const char* topic_motion   = "home/mmwave/motion";

// UART Pins ESP32-C3 Super Mini
#define RX_PIN 4   // GPIO4  ← Sensor TX
#define TX_PIN 5   // GPIO5  → Sensor RX

/* ========================== */

WiFiClient espClient;
PubSubClient mqtt(espClient);
HardwareSerial mmwave(1);

// Zustände
bool lastPresence = false;
bool lastMotion   = false;

// UART Zeilenpuffer
String lineBuffer = "";

// Radar-Logik
int lastRange = -1;
unsigned long lastValidMotion = 0;

// Feintuning (empfohlen)
const int RANGE_CHANGE_THRESHOLD = 15;        // Mindeständerung Range
const unsigned long MOTION_TIMEOUT   = 5000; // 5 s
const unsigned long PRESENCE_TIMEOUT = 15000;// 15 s

/* ========= WIFI ========= */

void setupWifi() {
  Serial.print("Verbinde WLAN");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWLAN verbunden");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());
}

/* ========= HOME ASSISTANT DISCOVERY ========= */

void publishHADiscovery() {

  mqtt.publish(
    "homeassistant/binary_sensor/esp32c3_mmwave_motion/config",
    "{"
    "\"name\":\"mmWave Motion\","
    "\"uniq_id\":\"esp32c3_mmwave_motion\","
    "\"stat_t\":\"home/mmwave/motion\","
    "\"pl_on\":\"ON\","
    "\"pl_off\":\"OFF\","
    "\"dev_cla\":\"motion\""
    "}",
    true
  );

  delay(200);

  mqtt.publish(
    "homeassistant/binary_sensor/esp32c3_mmwave_presence/config",
    "{"
    "\"name\":\"mmWave Presence\","
    "\"uniq_id\":\"esp32c3_mmwave_presence\","
    "\"stat_t\":\"home/mmwave/presence\","
    "\"pl_on\":\"ON\","
    "\"pl_off\":\"OFF\","
    "\"dev_cla\":\"occupancy\""
    "}",
    true
  );
}

/* ========= MQTT ========= */

void reconnectMQTT() {
  while (!mqtt.connected()) {
    Serial.print("Verbinde MQTT...");
    if (mqtt.connect("ESP32C3_MMWAVE", mqtt_user, mqtt_pass)) {
      Serial.println("OK");

      publishHADiscovery();

      mqtt.publish(topic_motion,   "OFF", true);
      mqtt.publish(topic_presence, "OFF", true);

      lastMotion = false;
      lastPresence = false;
      lastRange = -1;

    } else {
      Serial.print("FEHLER rc=");
      Serial.println(mqtt.state());
      delay(2000);
    }
  }
}

/* ========= SETUP ========= */

void setup() {
  Serial.begin(115200);
  delay(2000);
  Serial.println("ESP32 startet...");

  setupWifi();
  mqtt.setServer(mqtt_server, mqtt_port);

  mmwave.begin(
    115200,
    SERIAL_8N1,
    RX_PIN,
    TX_PIN
  );
}

/* ========= LOOP ========= */

void loop() {
  if (!mqtt.connected()) reconnectMQTT();
  mqtt.loop();

  // UART ASCII lesen
  while (mmwave.available()) {
    char c = mmwave.read();
    if (c == '\n') {
      handleLine(lineBuffer);
      lineBuffer = "";
    } else if (c != '\r') {
      lineBuffer += c;
    }
  }

  unsigned long now = millis();

  // Motion OFF
  if (lastMotion && (now - lastValidMotion > MOTION_TIMEOUT)) {
    mqtt.publish(topic_motion, "OFF", true);
    lastMotion = false;
  }

  // Presence OFF
  if (lastPresence && (now - lastValidMotion > PRESENCE_TIMEOUT)) {
    mqtt.publish(topic_presence, "OFF", true);
    lastPresence = false;
  }
}

/* ========= HMM-D LINE PARSER ========= */

void handleLine(String line) {
  line.trim();
  if (line.length() == 0) return;

  Serial.print("HMM-D: ");
  Serial.println(line);

  // Wir ignorieren dauerhaftes "ON" und reagieren NUR auf Range-Änderung
  if (line.startsWith("Range ")) {
    int range = line.substring(6).toInt();

    if (lastRange < 0) {
      lastRange = range;
      return;
    }

    int diff = abs(range - lastRange);

    if (diff >= RANGE_CHANGE_THRESHOLD) {
      lastValidMotion = millis();

      if (!lastMotion) {
        mqtt.publish(topic_motion, "ON", true);
        lastMotion = true;
      }

      if (!lastPresence) {
        mqtt.publish(topic_presence, "ON", true);
        lastPresence = true;
      }
    }

    lastRange = range;
  }
}