Communicate when leak is detected

secrets.h.example

@@ -0,0 +1,3 @@
+#define SECRET_SSID ""
+#define SECRET_PASS ""
+#define BROKER ""

water_sensor.ino

@@ -1,13 +1,30 @@
-#define ADC_PIN			A0
-#define RELAY_PIN		13
-#define RELAY_OFF		LOW
-#define RELAY_ON		HIGH
+#include <ArduinoMqttClient.h>
+#include <ESP8266WiFi.h>
 
-#define NUM_SAMPLES 	20
-#define SAMPLE_TIME     100
-#define WATER_THRESHOLD 750
+#include "secrets.h"
+
+#define ADC_PIN             A0
+#define RELAY_PIN           13
+#define RELAY_OFF           LOW
+#define RELAY_ON            HIGH
+
+#define NUM_SAMPLES         20
+#define SAMPLE_TIME         100
+#define WATER_THRESHOLD     750
+
+#define MESSAGE_INTERVAL    1000 * 60 * 60  // one hour
+
+WiFiClient wifiClient;
+MqttClient mqttClient(wifiClient);
+
+const char broker[] = BROKER;
+int        port     = 1883;
+const char topic[]  = "iot/water";
+
+String macAddress = String(ESP.getChipId(), HEX);
+String shortName = macAddress.substring(0, 4);
+String deviceName = "ws_" + shortName;
 
-bool leakDetected = false;
 
 void relayOn() {
 	Serial.println("Setting relay ON");
@@ -41,24 +58,99 @@ bool sampleWater() {
 	return waterDetected;
 }
 
+void sendWaterLeakTrue() {
+	mqttClient.beginMessage(topic);
+	mqttClient.print("{\"id\": \"");
+	mqttClient.print(deviceName);
+	mqttClient.print("\", \"water_leak\": true}");
+	mqttClient.endMessage();
+}
+
+void sendWaterLeakFalse() {
+	mqttClient.beginMessage(topic);
+	mqttClient.print("{\"id\": \"");
+	mqttClient.print(deviceName);
+	mqttClient.print("\", \"water_leak\": false}");
+	mqttClient.endMessage();
+}
+
 void setup() {
+	pinMode(RELAY_PIN, OUTPUT);
+
 	Serial.begin(115200);
-	//Serial.setDebugOutput(true);
+	delay(1000);
 
 	Serial.println();
 	Serial.println();
 	Serial.println();
 	Serial.println("===== BOOT UP =====");
 
-	pinMode(RELAY_PIN, OUTPUT);
+	WiFi.mode(WIFI_STA);
+	WiFi.begin(SECRET_SSID, SECRET_PASS);
+	Serial.print("[WIFI] Attempting to connect to wifi");
+	while (WiFi.status() != WL_CONNECTED) {
+		delay(500);
+		Serial.print(".");
+	}
+
+	Serial.println("");
+	Serial.println("[WIFI] Connected to the network");
+	Serial.println();
+
+	mqttClient.setId(deviceName);
+
+	Serial.print("[MQTT] Attempting to connect to the MQTT broker: ");
+	Serial.println(broker);
+
+	while (!mqttClient.connect(broker, port)) {
+		Serial.print("MQTT connection failed! Error code = ");
+		Serial.println(mqttClient.connectError());
+		delay(5000);
+	}
+
+	Serial.println("[MQTT] Connected to the MQTT broker.");
+
+	Serial.println("Turning relay on.");
 	relayOn();
 }
 
 void loop() {
-	if (sampleWater()) {
-		Serial.println("Water detected");
+	static unsigned long last_pos_message = 0;
+	static unsigned long last_neg_message = 0;
+
+	bool leakDetected = sampleWater();
+
+	if (leakDetected) {
 		relayOff();
+		Serial.println("Leak detected");
+	}
+
+	mqttClient.poll();
+
+	if (WiFi.status() != WL_CONNECTED) {
+		Serial.println("[WIFI] Lost connection. Reconnecting...");
+		WiFi.begin(SECRET_SSID, SECRET_PASS);
+		return;
+	} else if (!mqttClient.connected()) {
+		Serial.print("[MQTT] Not connected! Error code = ");
+		Serial.println(mqttClient.connectError());
+		Serial.println("[MQTT] Reconnecting...");
+		mqttClient.connect(broker, port);
+		return;
+	}
+
+	// TODO: replace this spaghetti with a state machine
+	if (leakDetected) {
+		if (!last_pos_message || millis() - last_pos_message > MESSAGE_INTERVAL) {
+			last_pos_message = millis();
+			last_neg_message = 0;
+			sendWaterLeakTrue();
+		}
 	} else {
-		Serial.println("No water");
+		if (!last_neg_message || millis() - last_neg_message > MESSAGE_INTERVAL) {
+			last_pos_message = 0;
+			last_neg_message = millis();
+			sendWaterLeakFalse();
+		}
 	}
 }