Mqtt (#8)

* use mqtt instead of ws

* update readme

README.md

@@ -4,17 +4,60 @@ Stream the sensor data
 ```mermaid
 sequenceDiagram
     participant ESP32 as ESP32
-    participant Client as WebSocket Client
+    participant Client as MQTT Client
     participant TouchSensor as Touch Sensor
 
-    ESP32->>+Client: Start WebSocket server
-    Client->>ESP32: Send message to get sensor data
-    ESP32->>+ESP32: Start streaming data
-    Client->>ESP32: Send message to stop streaming
-    ESP32-->>-ESP32: Stop streaming
+    ESP32->>+Client: Start streaming data
     Client->>ESP32: Send message to sleep
     ESP32->>+ESP32: Enter deep sleep mode
     TouchSensor->>ESP32: Touch GPIO 4
     ESP32-->>-ESP32: Wake up from deep sleep
     ESP32->>+ESP32: Start booting
 ```
+
+## Set up WiFi
+1. Connect to the ESP32's WiFi AP
+2. Open http://192.168.1.1
+3. Select the SSID and enter the password of the WiFi network
+
+Then the ESP32 will connect to the WiFi network and start streaming data.  
+The WiFi configuration will be saved in the flash memory.
+
+Check if the ESP32 is connected to the WiFi network
+```bash
+ping opencmm.local
+```
+
+## Install Mosquitto MQTT Broker
+
+ref. https://www.vultr.com/docs/install-mosquitto-mqtt-broker-on-ubuntu-20-04-server/
+
+/etc/mosquitto/conf.d/default.conf
+```
+listener 1883 0.0.0.0
+allow_anonymous false
+password_file /etc/mosquitto/passwd
+```
+
+### Receive data
+
+```bash
+mosquitto_sub -t 'sensor/data' -v -h 192.168.10.104 -u opencmm -P opencmm
+```
+
+### Send command to ESP32
+
+Update configuration
+```bash
+mosquitto_pub -t 'sensor/control' -h 192.168.10.104 -u opencmm -P opencmm -m '{"command": "config", "interval": 1000, "threshold": 100 }'
+```
+
+Go to sleep
+```bash
+mosquitto_pub -t 'sensor/control' -h 192.168.10.104 -u opencmm -P opencmm -m '{"command": "deepSleep" }'
+```
+
+Reset WiFi
+```bash
+mosquitto_pub -t 'sensor/control' -h 192.168.10.104 -u opencmm -P opencmm -m '{"command": "resetWifi" }'
+```

platformio.ini

@@ -16,4 +16,5 @@ monitor_speed = 115200
 lib_deps = 
 	links2004/WebSockets@^2.4.1
 	adafruit/Adafruit ADS1X15@^2.4.0
-	bblanchon/ArduinoJson@^6.21.3
+	bblanchon/ArduinoJson@^6.21.3
+	knolleary/PubSubClient@^2.8

src/main.cpp

@@ -5,64 +5,100 @@
 #include <Sensor.h>
 #include <ESPmDNS.h>
 #include <ArduinoJson.h>
+#include <PubSubClient.h>
 
 void ledBlink();
+void callback(char* topic, byte* message, unsigned int length);
+void reconnect();
+void publishSensorData(int sensorData);
 
 const int touchPin = 4; // GPIO4 as the touch-sensitive pin
 int sensorData = 0;
 int interval = 1000; // 1 second
 int threshold = 100;
 const char* hostname = "opencmm";
+const char* mqttServer = "192.168.10.104";
+const int mqttPort = 1883;
+const char* mqttUser = "opencmm";
+const char* mqttPassword = "opencmm";
 
-WebSocketsServer webSocket(81);
+const char* clientId = "ESP32Client";
+const char* sensorTopic = "sensor/data";
+const char* controlTopic = "sensor/control";
 
-bool streaming = false;
 
-void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
+WiFiClient espClient;
+PubSubClient client(espClient);
+
+void touchCallback()
 {
-  switch (type)
-  {
-  case WStype_DISCONNECTED:
-    // streaming = false; // Stop streaming data when a client disconnects
-    break;
-  case WStype_TEXT:
-  {
-    const uint8_t size = JSON_OBJECT_SIZE(3);
-    StaticJsonDocument<size> json;
-    DeserializationError err = deserializeJson(json, payload);
-    if (err)
-    {
-      Serial.print(F("deserializeJson() failed with code "));
-      Serial.println(err.c_str());
-    }
-    const char *command = json["command"];
+  // wake up from deep sleep
+  Serial.println("Touch detected");
+  // turn on sensor
+  switchSensor(true);
+  ledBlink();
+}
 
-    if (strcmp(command, "start") == 0)
-    {
-      streaming = true; // Start streaming data when "startStreaming" message is received
-      const int _interval = json["interval"];
+void setup()
+{
+  Serial.begin(115200);
+  checkWifiInfo();
+  MDNS.begin(hostname);
+  setupSensor();
+
+  client.setServer(mqttServer, mqttPort);
+  client.setCallback(callback);
+
+  touchAttachInterrupt(touchPin, touchCallback, 40); // Attach touch interrupt
+
+  // Configure Touchpad as wakeup source
+  esp_sleep_enable_touchpad_wakeup();
+
+  ledBlink();
+}
+
+void callback(char* topic, byte* payload, unsigned int length) {
+  Serial.print("Message arrived on topic: ");
+  Serial.println(topic);
+
+  char receivedJson[200];
+  for (int i = 0; i < length; i++) {
+    receivedJson[i] = (char)payload[i];
+  }
+  receivedJson[length] = '\0';
+  // Deserialize the received JSON string
+  const uint8_t size = JSON_OBJECT_SIZE(3);
+  StaticJsonDocument<size> jsonDoc;
+  DeserializationError error = deserializeJson(jsonDoc, receivedJson);
+
+  if (error) {
+    Serial.print("Failed to parse JSON: ");
+    Serial.println(error.c_str());
+  } else {
+    const char *command = jsonDoc["command"];
+    if (strcmp(command, "config") == 0) {
+      const int _interval = jsonDoc["interval"];
       if (isIntervalValid(_interval))
       {
         interval = _interval;
         Serial.println("Interval: " + String(interval));
       }
 
-      const int _threshold = json["threshold"];
+      const int _threshold = jsonDoc["threshold"];
       if (isThresholdValid(_threshold))
       {
         threshold = _threshold;
         Serial.println("Threshold: " + String(threshold));
       }
-      Serial.println("Streaming started");
-    }
-    else if (strcmp(command, "stop") == 0)
-    {
-      streaming = false; // Stop streaming data when "stopStreaming" message is received
-      Serial.println("Streaming stopped");
-    }
-    else if (strcmp(command, "deepSleep") == 0)
+      Serial.println("Configured");
+      Serial.print("Received JSON - Threshold: ");
+      Serial.print(threshold);
+      Serial.print(", Interval: ");
+      Serial.print(interval);
+      Serial.print(", Command: ");
+      Serial.println(command);
+    } else if (strcmp(command, "deepSleep") == 0)
     {
-      streaming = false;
       Serial.println("Going to sleep now");
       delay(1000);
       // turn off sensor
@@ -74,61 +110,33 @@ void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length)
       resetWifiCredentialsWithWs();
     }
   }
-
-  break;
-  default:
-    break;
-  }
 }
 
-void touchCallback()
-{
-  // wake up from deep sleep
-  Serial.println("Touch detected");
-  // turn on sensor
-  switchSensor(true);
-  ledBlink();
-}
-
-void setup()
-{
-  Serial.begin(115200);
-  checkWifiInfo();
-  MDNS.begin(hostname);
-  setupSensor();
-
-  touchAttachInterrupt(touchPin, touchCallback, 40); // Attach touch interrupt
-
-  // Configure Touchpad as wakeup source
-  esp_sleep_enable_touchpad_wakeup();
-
-  ledBlink();
-
-  webSocket.begin();
-  webSocket.onEvent(webSocketEvent);
+void publishSensorData(int sensorData) {
+  char message[20];
+  snprintf(message, 20, "%d", sensorData);
+  client.publish(sensorTopic, message);
 }
 
 void loop()
 {
   if (WiFi.status() == WL_CONNECTED)
   {
-    webSocket.loop();
+    if (!client.connected()) {
+      reconnect();
+    }
+    client.loop();
 
-    // If streaming is enabled, get sensor data and send it to the client
-    if (streaming)
-    {
-      int currentData = getSensorData();
-      // if the difference is greater than threshold, send data
-      if (abs(currentData - sensorData) < threshold)
-      {
-        return;
-      }
-      sensorData = currentData;
-      String dataStr = String(currentData);
-      Serial.println(dataStr);
-      webSocket.broadcastTXT(dataStr.c_str(), dataStr.length());
-      delay(interval);
+    int currentData = getSensorData();
+    // if the difference is greater than threshold, send data
+    if (abs(currentData - sensorData) < threshold) {
+      return;
     }
+    sensorData = currentData;
+    Serial.println(currentData);
+    publishSensorData(currentData);
+
+    delay(interval);
   } else {
     runServer();
     delay(1000);
@@ -138,9 +146,23 @@ void loop()
   }
 }
 
+void reconnect() {
+  while (!client.connected()) {
+    Serial.println("Attempting MQTT connection...");
+    if (client.connect(clientId, mqttUser, mqttPassword)) {
+      Serial.println("Connected to MQTT broker");
+      client.subscribe(controlTopic);
+    } else {
+      Serial.print("Failed, rc=");
+      Serial.print(client.state());
+      Serial.println(" Trying again in 5 seconds...");
+      delay(5000);
+    }
+  }
+}
+
 // LED blink
-void ledBlink()
-{
+void ledBlink() {
   digitalWrite(LED_BUILTIN, HIGH);
   delay(500);
   digitalWrite(LED_BUILTIN, LOW);