We had some very (very!) hot days here in Sydney, up to 40 DegC over several days. After a day in the office, you open the door to your apartment and… 50 DegC 🙁 I looked for a solution to cool down home right after i left the office – with my phone – using MQTT 😉

Hardware

I am using three components for my project. The MCU, an adapter board and the IR-LED

NodeMCU

ESP8266
4Mbyte ROM
On-board USB/UART

Grove Base Shield for NodeMCU

5 Digital connectors
2 I2C sockets
1 Analog connectors (A0)
Power indicator LED

Shop | Wiki

Grove – Infrared Emitter

Voltage: 3.3-5V
Distance:10m

Shop | Wiki

Software

The Basics

The project is based on the Arduino core for ESP8266 and uses several additional libraries. I am using the platform.io IDE for development. The advantages are the fully integrated build and deployment process (via USB or over WiFi), the library manager and the code completion and linting. You can download my complete platform.io project here.

You’ll also need an MQTT server like RabbitMQ to send commands and receive the status. If you are familiar with Docker, you should read my previous post Dockerize RabbitMQ to get a server up and running in no time. If not: There are several binary pages on the RabbitMQ Website.

Basic structure:

Connection to the WiFi
- Managing OTA updates
Connection to the MQTT Server
- Subscribing to a command channel
- Emitting current state to a status channel
Emitting IR commands to the A/C

HeatpumpIR Library

The HeatpumpIR library is the heart of the project. Its designed to expose a unified interface for several different A/C manufacturers like Daikin, Samsung, Panasonic and other. The library is compatible to Arduino and ESP8266 MCUs.

The usage is really simple, have a look at the example code

// Include the appropriate header for your A/C
#include <DaikinHeatpumpIR.h>

// Define a ir sender at port D2
IRSenderBitBang irSender(D2);

// Define the heatpump 
DaikinHeatpumpIR *heatpump;

void setup() {
// ...
}

void main() {
  // Send the command
  heatpump->send(irSender, POWER_ON, MODE_COOL, FAN_AUTO, 24, VDIR_AUTO, HDIR_AUTO);
}

// Include the appropriate header for your A/C

#include <DaikinHeatpumpIR.h>

// Define a ir sender at port D2

IRSenderBitBang irSender(D2);

// Define the heatpump

DaikinHeatpumpIR *heatpump;

void setup() {

// ...

}

void main() {

// Send the command

heatpump->send(irSender, POWER_ON, MODE_COOL, FAN_AUTO, 24, VDIR_AUTO, HDIR_AUTO);

}

This command will power on the A/C, set the mode cooling, the fan to auto, 24 degC and both swings to auto.

You can find a list of possible values here.

If you don’t have a Daikin A/C, have a look into the library and search for your brand. Just change the #include and you should be good to go.

The complete code

Depending on your IDE you have to search for the libraries by yourself. You’ll need PubSubClient, HeatpumpIR and Timer.

Again: It’s easier to install the Platform.io IDE and use my package 🙂

In both cases you have to modify several defines on top of the main.ino, here are the most relevant:

Name	Description
IR_SEND_PIN	The PIN where the IR LED is connected
WIFI_SSID	Your WiFi network name
WIFI_PASS	WiFi password
MQTT_HOST	Mqtt hostname like mqtt.mydomain.com
MQTT_USER	MQTT Username
MQTT_PASS	MQTT Password

#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>
#include <PubSubClient.h>                   // MQTT
#include <DaikinHeatpumpIR.h>
#include "Timer.h"

#define TOPSZ                  60           // Max number of characters in topic string
#define MESSZ                  240          // Max number of characters in JSON message string
#define IR_SEND_PIN 12


#define WIFI_SSID "mysecretwifi"
#define WIFI_PASS "superpassword"
#define MQTT_HOST "mymqtthost.com"
#define MQTT_PORT 1883
#define MQTT_USER "mqttuser"
#define MQTT_PASS "mqttpassword"
#define MQTT_CLIENT_ID "daikinremote"
#define MQTT_STATUS_CHANNEL "stat/daikin"
#define MQTT_COMMAND_CHANNEL "cmnd/daikin/#" // dont miss the # at the end!


WiFiClient espClient;               // Wifi Client
PubSubClient mqttClient(espClient);   // MQTT Client

IRSenderBitBang irSender(IR_SEND_PIN);

DaikinHeatpumpIR *heatpump;

Timer t;

// Set defaults
uint8_t AC_POWER = POWER_OFF,
        AC_MODE = MODE_AUTO,
        AC_FAN = FAN_AUTO,
        AC_TEMP = 24,
        AC_VSWING = VDIR_AUTO,
        AC_HSWING = HDIR_AUTO;

void setup() {
  Serial.begin(115200);
  delay(10);
  Serial.println("Booting");

  initWIFI();
  initOTA();

  Serial.println("Ready");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  // Init loop timers
  t.every(5000, fiveLoop);
  t.every(10000, tenLoop);

  heatpump = new DaikinHeatpumpIR();

  initMQTT();
}

void loop() {
  ArduinoOTA.handle();
  mqttClient.loop();
  t.update();
}


void tenLoop() {
  Serial.println("Ping...");
  publishState();
}

// Reconnect to mqtt every 5 seconds if connection is lost
void fiveLoop() {
  if (!mqttClient.connected()) {
    reconnectMQTT();
  }
}

void initMQTT() {
  mqttClient.setServer(MQTT_HOST, MQTT_PORT);
  if (!mqttClient.connected()) {
    reconnectMQTT();
  }
  publishState();
}

void mqttDataCb(char* topic, byte* data, unsigned int data_len) {
  char svalue[MESSZ];
  char topicBuf[TOPSZ];
  char dataBuf[data_len+1];

  strncpy(topicBuf, topic, sizeof(topicBuf));
  memcpy(dataBuf, data, sizeof(dataBuf));
  dataBuf[sizeof(dataBuf)-1] = 0;

  snprintf_P(svalue, sizeof(svalue), PSTR("RSLT: Receive topic %s, data size %d, data %s"), topicBuf, data_len, dataBuf);
  Serial.println(svalue);

  // Extract command
  memmove(topicBuf, topicBuf+sizeof(MQTT_COMMAND_CHANNEL)-2, sizeof(topicBuf)-sizeof(MQTT_COMMAND_CHANNEL));

  int16_t payload = atoi(dataBuf);     // -32766 - 32767

  if (!strcmp(topicBuf, "power")) {
    Serial.print("power ");
    Serial.println(payload);
    AC_POWER = payload;
  } else if (!strcmp(topicBuf, "mode")) {
    Serial.print("mode ");
    Serial.println(payload);
    AC_MODE = payload;
  } else if (!strcmp(topicBuf, "fan")) {
    Serial.print("fan ");
    Serial.println(payload);
    AC_FAN = payload;
  } else if (!strcmp(topicBuf, "temp")) {
    Serial.print("temp ");
    Serial.println(payload);
    AC_TEMP = payload;
  }

  heatpump->send(irSender, AC_POWER, AC_MODE, AC_FAN, AC_TEMP, AC_VSWING, AC_HSWING);
  publishState();
}

void publishState() {
  char message[MESSZ];
  sprintf(
    message,
    "{\"power\":%d,\"mode\":%d, \"fan\":%d,\"temp\":%d,\"vswing\":%d,\"hswing\":%d}",
    AC_POWER, AC_MODE, AC_FAN, AC_TEMP, AC_VSWING, AC_HSWING
  );
  mqttClient.publish(MQTT_STATUS_CHANNEL, message, true);
}

void reconnectMQTT() {
  // Loop until we're reconnected
  Serial.println("Attempting MQTT connection...");
  // Attempt to connect
  if (mqttClient.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASS)) {
    Serial.println("connected");
    mqttClient.setCallback(mqttDataCb);
    mqttClient.subscribe(MQTT_COMMAND_CHANNEL);
  } else {
    Serial.print("failed, rc=");
    Serial.println(mqttClient.state());
  }
}



void initOTA() {
  // Port defaults to 8266
  // ArduinoOTA.setPort(8266);

  // Hostname defaults to esp8266-[ChipID]
  // ArduinoOTA.setHostname("myesp8266");

  // No authentication by default
  // ArduinoOTA.setPassword("admin");

  // Password can be set with it's md5 value as well
  // MD5(admin) = 21232f297a57a5a743894a0e4a801fc3
  // ArduinoOTA.setPasswordHash("21232f297a57a5a743894a0e4a801fc3");

  ArduinoOTA.onStart([]() {
    String type;
    if (ArduinoOTA.getCommand() == U_FLASH)
      type = "sketch";
    else // U_SPIFFS
      type = "filesystem";

    // NOTE: if updating SPIFFS this would be the place to unmount SPIFFS using SPIFFS.end()
    Serial.println("Start updating " + type);
  });
  ArduinoOTA.onEnd([]() {
    Serial.println("\nEnd");
  });
  ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {
    Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
  });
  ArduinoOTA.onError([](ota_error_t error) {
    Serial.printf("Error[%u]: ", error);
    if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");
    else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");
    else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");
    else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");
    else if (error == OTA_END_ERROR) Serial.println("End Failed");
  });
  ArduinoOTA.begin();
}


void initWIFI() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("Connection Failed! Rebooting...");
    delay(5000);
    ESP.restart();
  }
}

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#include <ESP8266WiFi.h>

#include <ESP8266mDNS.h>

#include <WiFiUdp.h>

#include <ArduinoOTA.h>

#include <PubSubClient.h> // MQTT

#include <DaikinHeatpumpIR.h>

#include "Timer.h"

#define TOPSZ 60 // Max number of characters in topic string

#define MESSZ 240 // Max number of characters in JSON message string

#define IR_SEND_PIN 12

#define WIFI_SSID "mysecretwifi"

#define WIFI_PASS "superpassword"

#define MQTT_HOST "mymqtthost.com"

#define MQTT_PORT 1883

#define MQTT_USER "mqttuser"

#define MQTT_PASS "mqttpassword"

#define MQTT_CLIENT_ID "daikinremote"

#define MQTT_STATUS_CHANNEL "stat/daikin"

#define MQTT_COMMAND_CHANNEL "cmnd/daikin/#" // dont miss the # at the end!

WiFiClient espClient; // Wifi Client

PubSubClient mqttClient(espClient); // MQTT Client

IRSenderBitBang irSender(IR_SEND_PIN);

DaikinHeatpumpIR *heatpump;

Timer t;

// Set defaults

uint8_t AC_POWER = POWER_OFF,

AC_MODE = MODE_AUTO,

AC_FAN = FAN_AUTO,

AC_TEMP = 24,

AC_VSWING = VDIR_AUTO,

AC_HSWING = HDIR_AUTO;

void setup() {

Serial.begin(115200);

delay(10);

Serial.println("Booting");

initWIFI();

initOTA();

Serial.println("Ready");

Serial.print("IP address: ");

Serial.println(WiFi.localIP());

// Init loop timers

t.every(5000, fiveLoop);

t.every(10000, tenLoop);

heatpump = new DaikinHeatpumpIR();

initMQTT();

}

void loop() {

ArduinoOTA.handle();

mqttClient.loop();

t.update();

}

void tenLoop() {

Serial.println("Ping...");

publishState();

}

// Reconnect to mqtt every 5 seconds if connection is lost

void fiveLoop() {

if (!mqttClient.connected()) {

reconnectMQTT();

}

void initMQTT() {

mqttClient.setServer(MQTT_HOST, MQTT_PORT);

if (!mqttClient.connected()) {

reconnectMQTT();

}

publishState();

}

void mqttDataCb(char* topic, byte* data, unsigned int data_len) {

char svalue[MESSZ];

char topicBuf[TOPSZ];

char dataBuf[data_len+1];

strncpy(topicBuf, topic, sizeof(topicBuf));

memcpy(dataBuf, data, sizeof(dataBuf));

dataBuf[sizeof(dataBuf)-1] = 0;

snprintf_P(svalue, sizeof(svalue), PSTR("RSLT: Receive topic %s, data size %d, data %s"), topicBuf, data_len, dataBuf);

Serial.println(svalue);

// Extract command

memmove(topicBuf, topicBuf+sizeof(MQTT_COMMAND_CHANNEL)-2, sizeof(topicBuf)-sizeof(MQTT_COMMAND_CHANNEL));

int16_t payload = atoi(dataBuf); // -32766 - 32767

if (!strcmp(topicBuf, "power")) {

Serial.print("power ");

Serial.println(payload);

AC_POWER = payload;

} else if (!strcmp(topicBuf, "mode")) {

Serial.print("mode ");

Serial.println(payload);

AC_MODE = payload;

} else if (!strcmp(topicBuf, "fan")) {

Serial.print("fan ");

Serial.println(payload);

AC_FAN = payload;

} else if (!strcmp(topicBuf, "temp")) {

Serial.print("temp ");

Serial.println(payload);

AC_TEMP = payload;

}

heatpump->send(irSender, AC_POWER, AC_MODE, AC_FAN, AC_TEMP, AC_VSWING, AC_HSWING);

publishState();

}

void publishState() {

char message[MESSZ];

sprintf(

message,

"{\"power\":%d,\"mode\":%d, \"fan\":%d,\"temp\":%d,\"vswing\":%d,\"hswing\":%d}",

AC_POWER, AC_MODE, AC_FAN, AC_TEMP, AC_VSWING, AC_HSWING

);

mqttClient.publish(MQTT_STATUS_CHANNEL, message, true);

}

void reconnectMQTT() {

// Loop until we're reconnected

Serial.println("Attempting MQTT connection...");

// Attempt to connect

if (mqttClient.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASS)) {

Serial.println("connected");

mqttClient.setCallback(mqttDataCb);

mqttClient.subscribe(MQTT_COMMAND_CHANNEL);

} else {

Serial.print("failed, rc=");

Serial.println(mqttClient.state());

}

void initOTA() {

// Port defaults to 8266

// ArduinoOTA.setPort(8266);

// Hostname defaults to esp8266-[ChipID]

// ArduinoOTA.setHostname("myesp8266");

// No authentication by default

// ArduinoOTA.setPassword("admin");

// Password can be set with it's md5 value as well

// MD5(admin) = 21232f297a57a5a743894a0e4a801fc3

// ArduinoOTA.setPasswordHash("21232f297a57a5a743894a0e4a801fc3");

ArduinoOTA.onStart([]() {

String type;

if (ArduinoOTA.getCommand() == U_FLASH)

type = "sketch";

else // U_SPIFFS

type = "filesystem";

// NOTE: if updating SPIFFS this would be the place to unmount SPIFFS using SPIFFS.end()

Serial.println("Start updating " + type);

});

ArduinoOTA.onEnd([]() {

Serial.println("\nEnd");

});

ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {

Serial.printf("Progress: %u%%\r", (progress / (total / 100)));

});

ArduinoOTA.onError([](ota_error_t error) {

Serial.printf("Error[%u]: ", error);

if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");

else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");

else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");

else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");

else if (error == OTA_END_ERROR) Serial.println("End Failed");

});

ArduinoOTA.begin();

}

void initWIFI() {

WiFi.mode(WIFI_STA);

WiFi.begin(WIFI_SSID, WIFI_PASS);

while (WiFi.waitForConnectResult() != WL_CONNECTED) {

Serial.println("Connection Failed! Rebooting...");

delay(5000);

ESP.restart();

}

Example usage

Software uploaded, Hardware connected, WiFi and MQTT connection ok? Good! 🙂 Time to send the first command via MQTT. On MacOS i am using mqtt.fx to connect to my MQTT server. You can of course use another tool, it’s up to you to find and configure them 😉

The software is listening for commands on a specific topic configured via the constant MQTT_COMMAND_CHANNEL. The default configuration is “cmnd/daikin/#“. To set the power on the A/C, you just publish “1” to the topic “cmnd/daikin/power“. The MCU will now send the command via IR and post the current values of every setting (power, mode, fan etc.) as JSON to the topic “stat/daikin”

{"power":1,"mode":3, "fan":2,"temp":23,"vswing":0,"hswing":0}

Command overview and value mapping

Command	Descr → Value
cmnd/daikin/power	POWER_OFF → 0 POWER_ON → 1
cmnd/daikin/mode	MODE_AUTO → 1 MODE_HEAT → 2 MODE_COOL → 3 MODE_DRY → 4 MODE_FAN → 5
cmnd/daikin/fan	FAN_AUTO → 0 FAN_1 → 1 FAN_2 → 2 FAN_3 → 3 FAN_4 → 4 FAN_5 → 5
cmnd/daikin/temp	Numeric value
♦	VDIR_AUTO → 0
♦	HDIR_AUTO → 0

♦ The swing functionality is not implemented for now – feel free to do it by yourself 😉

Android App anyone?

I’m using a nice Android app called MQTT Dash