Arduino/ESP8266-MQTT-Teufel-Subwoofer/ESP8266-MQTT-Teufel-Subwoofer.ino

/**********************************************************************
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 Nis Wechselberg
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 **********************************************************************/

/**********************************************************************
 * ESP8266-MQTT-Teufel-Subwoofer
 *
 * Links the ESP8266 based subwoofer control board to an mqtt broker.
 * The program uses multiple topics for incoming and outgoing messages.
 * Incoming topics:
 * - <mqtt_device>/power
 * Outgoing topics:
 *
 **********************************************************************/

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include "ESP8266-MQTT-Teufel-Subwoofer.h"

#define DEBUGTOSERIAL 1

// Timestamp for last publish
long lastMsg = 0;
long publishInterval = 5000;
// Message buffer
char msg[50];

// Last known power state
int powerState = 0;

// Pin config
const int powerSwitchPin = 12;
const int powerProbePin = 13;

// Global mqtt client object
WiFiClient espClient;
PubSubClient client(espClient);

/*
 * Initial setup for arduino
 */
void setup() {
  
  // Configure pins
  pinMode(powerSwitchPin, OUTPUT);
  digitalWrite(powerSwitchPin, LOW);
  
  // Configure serial port
  Serial.begin(115200);
  delay(10);

  // Prepare WiFi connection
  setup_wifi();

  // Connect to mqtt broker
  client.setServer(mqtt_server, 1883);
  client.setCallback(incoming_mqtt);
}

/*
 * Prepares the wireless connection
 */
void setup_wifi() {
  // Connect to the WiFi as a client
  WiFi.mode(WIFI_STA);

  // Do the connection
  if (DEBUGTOSERIAL) {
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);
  }
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    if (DEBUGTOSERIAL) {
      Serial.print(".");
    }
  }
  if (DEBUGTOSERIAL) {
    Serial.println("");
    Serial.println("WiFi connected");

    // Print IP address to serial
    Serial.print("My IP address: ");
    Serial.println(WiFi.localIP());
  }
}

/*
 * Callback method for incoming mqtt messages
 */
void incoming_mqtt(char* topic, byte* payload, unsigned int length) {
  if (DEBUGTOSERIAL) {
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("] ");
    for (int i = 0; i < length; i++) {
      Serial.print((char)payload[i]);
    }
    Serial.println();
  }

  if (strcmp(topic, mqtt_topic_power) == 0) {
    if (length == 1) {
      if (DEBUGTOSERIAL) {
        Serial.println("Setting new power state");
      }
      if ((char)payload[0] == '0') {
        if (powerState ==  HIGH) {
          // Turn power off
          togglePowerButton();
        }
      } else {
        if (powerState == LOW) {
          // Turn power off
          togglePowerButton();
        }
      }
    }    
  }
}

/*
 * Blocking reconnect to the mqtt broker
 */
void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    if (DEBUGTOSERIAL) {
      Serial.print("Attempting MQTT connection...");
    }
    // Attempt to connect
    if (client.connect(mqtt_device_name)) {
      if (DEBUGTOSERIAL) {
        Serial.println("connected");
      }
      // subscribe to incoming topics
      client.subscribe(mqtt_topic_power);
    } else {
      if (DEBUGTOSERIAL) {
        Serial.print("failed, rc=");
        Serial.print(client.state());
        Serial.println(" try again in 5 seconds");
      }
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void togglePowerButton() {
  digitalWrite(powerSwitchPin, HIGH);
  delay(100);
  digitalWrite(powerSwitchPin, LOW);
}

void updatePowerState() {
  // Read value from digital pin (Levels are inverted)
  powerState = 1 - digitalRead(powerProbePin);

  if (DEBUGTOSERIAL) {
    Serial.print("New power state determined: ");
    Serial.println(powerState);
  }
  
  snprintf(msg, 49, "%d", powerState);
  client.publish(mqtt_topic_powerState, msg);
}

void loop() {
  // Ensure MQTT connection
  if (!client.connected()) {
    reconnect();
  }

  // Check the inbox
  client.loop();

  // Maybe push the current status
  long now = millis();
  if (now - lastMsg > publishInterval) {
    lastMsg = now;
    updatePowerState();
  }
}