mqtt_esp8266_brightness.ino

/*
 * ESP8266 MQTT Lights for Home Assistant.
 * See https://github.com/corbanmailloux/esp-mqtt-rgb-led
 */

// https://github.com/bblanchon/ArduinoJson
#include <ArduinoJson.h>

#include <ESP8266WiFi.h>

// http://pubsubclient.knolleary.net/
#include <PubSubClient.h>

const int redPin = 0;
const int txPin = 1; // On-board blue LED
// const int greenPin = 2;
// const int bluePin = 3;

const char* ssid = "{WIFI-SSID}";
const char* password = "{WIFI-PASSWORD}";

const char* mqtt_server = "{MQTT-SERVER}";
const char* mqtt_username = "{MQTT-USERNAME}";
const char* mqtt_password = "{MQTT-PASSWORD}";

const char* client_id = "ESPBrightnessLED"; // Must be unique on the MQTT network

// Topics
const char* light_state_topic = "home/brightness1";
const char* light_set_topic = "home/brightness1/set";

const char* on_cmd = "ON";
const char* off_cmd = "OFF";

const int BUFFER_SIZE = JSON_OBJECT_SIZE(8);

// Maintained state for reporting to HA
byte red = 255;
// byte green = 255;
// byte blue = 255;
byte brightness = 255;

// Real values to write to the LEDs (ex. including brightness and state)
byte realRed = 0;
// byte realGreen = 0;
// byte realBlue = 0;

bool stateOn = false;

// Globals for fade/transitions
bool startFade = false;
unsigned long lastLoop = 0;
int transitionTime = 0;
bool inFade = false;
int loopCount = 0;
int stepR; //, stepG, stepB;
int redVal; //, grnVal, bluVal;

// Globals for flash
bool flash = false;
bool startFlash = false;
int flashLength = 0;
unsigned long flashStartTime = 0;
byte flashRed = red;
// byte flashGreen = green;
// byte flashBlue = blue;
byte flashBrightness = brightness;

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  pinMode(redPin, OUTPUT);
  // pinMode(greenPin, OUTPUT);
  // pinMode(bluePin, OUTPUT);

  pinMode(txPin, OUTPUT);
  digitalWrite(txPin, HIGH); // Turn off the on-board LED

  analogWriteRange(255);

  // Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

  /*
  SAMPLE PAYLOAD:
    {
      "brightness": 120,
      "flash": 2,
      "transition": 5,
      "state": "ON"
    }
  */
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");

  char message[length + 1];
  for (int i = 0; i < length; i++) {
    message[i] = (char)payload[i];
  }
  message[length] = '\0';
  Serial.println(message);

  if (!processJson(message)) {
    return;
  }

  if (stateOn) {
    // Update lights
    realRed = map(red, 0, 255, 0, brightness);
    // realGreen = map(green, 0, 255, 0, brightness);
    // realBlue = map(blue, 0, 255, 0, brightness);
  }
  else {
    realRed = 0;
    // realGreen = 0;
    // realBlue = 0;
  }

  startFade = true;
  inFade = false; // Kill the current fade

  sendState();
}

bool processJson(char* message) {
  StaticJsonBuffer<BUFFER_SIZE> jsonBuffer;

  JsonObject& root = jsonBuffer.parseObject(message);

  if (!root.success()) {
    Serial.println("parseObject() failed");
    return false;
  }

  if (root.containsKey("state")) {
    if (strcmp(root["state"], on_cmd) == 0) {
      stateOn = true;
    }
    else if (strcmp(root["state"], off_cmd) == 0) {
      stateOn = false;
    }
  }

  // If "flash" is included, treat RGB and brightness differently
  if (root.containsKey("flash")) {
    flashLength = (int)root["flash"] * 1000;

    if (root.containsKey("brightness")) {
      flashBrightness = root["brightness"];
    }
    else {
      flashBrightness = brightness;
    }

    // if (root.containsKey("color")) {
    //   flashRed = root["color"]["r"];
    //   flashGreen = root["color"]["g"];
    //   flashBlue = root["color"]["b"];
    // }
    // else {
    //   flashRed = red;
    //   flashGreen = green;
    //   flashBlue = blue;
    // }

    flashRed = map(flashRed, 0, 255, 0, flashBrightness);
    // flashGreen = map(flashGreen, 0, 255, 0, flashBrightness);
    // flashBlue = map(flashBlue, 0, 255, 0, flashBrightness);

    flash = true;
    startFlash = true;
  }
  else { // Not flashing
    flash = false;

    // if (root.containsKey("color")) {
    //   red = root["color"]["r"];
    //   green = root["color"]["g"];
    //   blue = root["color"]["b"];
    // }

    if (root.containsKey("brightness")) {
      brightness = root["brightness"];
    }

    if (root.containsKey("transition")) {
      transitionTime = root["transition"];
    }
    else {
      transitionTime = 0;
    }
  }

  return true;
}

void sendState() {
  StaticJsonBuffer<BUFFER_SIZE> jsonBuffer;

  JsonObject& root = jsonBuffer.createObject();

  root["state"] = (stateOn) ? on_cmd : off_cmd;
  // JsonObject& color = root.createNestedObject("color");
  // color["r"] = red;
  // color["g"] = green;
  // color["b"] = blue;

  root["brightness"] = brightness;

  char buffer[root.measureLength() + 1];
  root.printTo(buffer, sizeof(buffer));

  client.publish(light_state_topic, buffer, true);
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect(client_id, mqtt_username, mqtt_password)) {
      Serial.println("connected");
      client.subscribe(light_set_topic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setColor(int inR) { //, int inG, int inB) {
  analogWrite(redPin, inR);
  // analogWrite(greenPin, inG);
  // analogWrite(bluePin, inB);

  Serial.println("Setting LEDs:");
  // Serial.print("r: ");
  Serial.println(inR);
  // Serial.print(", g: ");
  // Serial.print(inG);
  // Serial.print(", b: ");
  // Serial.println(inB);
}

void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  if (flash) {
    if (startFlash) {
      startFlash = false;
      flashStartTime = millis();
    }

    if ((millis() - flashStartTime) <= flashLength) {
      if ((millis() - flashStartTime) % 1000 <= 500) {
        setColor(flashRed); //, flashGreen, flashBlue);
      }
      else {
        setColor(0); //, 0, 0);
        // If you'd prefer the flashing to happen "on top of"
        // the current color, uncomment the next line.
        // setColor(realRed, realGreen, realBlue);
      }
    }
    else {
      flash = false;
      setColor(realRed); //, realGreen, realBlue);
    }
  }

  if (startFade) {
    // If we don't want to fade, skip it.
    if (transitionTime == 0) {
      setColor(realRed); //, realGreen, realBlue);

      redVal = realRed;
      // grnVal = realGreen;
      // bluVal = realBlue;

      startFade = false;
    }
    else {
      loopCount = 0;
      stepR = calculateStep(redVal, realRed);
      // stepG = calculateStep(grnVal, realGreen);
      // stepB = calculateStep(bluVal, realBlue);

      inFade = true;
    }
  }

  if (inFade) {
    startFade = false;
    unsigned long now = millis();
    if (now - lastLoop > transitionTime) {
      if (loopCount <= 1020) {
        lastLoop = now;
        
        redVal = calculateVal(stepR, redVal, loopCount);
        // grnVal = calculateVal(stepG, grnVal, loopCount);
        // bluVal = calculateVal(stepB, bluVal, loopCount);
        
        setColor(redVal); //, grnVal, bluVal); // Write current values to LED pins

        Serial.print("Loop count: ");
        Serial.println(loopCount);
        loopCount++;
      }
      else {
        inFade = false;
      }
    }
  }
}

// From https://www.arduino.cc/en/Tutorial/ColorCrossfader
/* BELOW THIS LINE IS THE MATH -- YOU SHOULDN'T NEED TO CHANGE THIS FOR THE BASICS
* 
* The program works like this:
* Imagine a crossfade that moves the red LED from 0-10, 
*   the green from 0-5, and the blue from 10 to 7, in
*   ten steps.
*   We'd want to count the 10 steps and increase or 
*   decrease color values in evenly stepped increments.
*   Imagine a + indicates raising a value by 1, and a -
*   equals lowering it. Our 10 step fade would look like:
* 
*   1 2 3 4 5 6 7 8 9 10
* R + + + + + + + + + +
* G   +   +   +   +   +
* B     -     -     -
* 
* The red rises from 0 to 10 in ten steps, the green from 
* 0-5 in 5 steps, and the blue falls from 10 to 7 in three steps.
* 
* In the real program, the color percentages are converted to 
* 0-255 values, and there are 1020 steps (255*4).
* 
* To figure out how big a step there should be between one up- or
* down-tick of one of the LED values, we call calculateStep(), 
* which calculates the absolute gap between the start and end values, 
* and then divides that gap by 1020 to determine the size of the step  
* between adjustments in the value.
*/
int calculateStep(int prevValue, int endValue) {
    int step = endValue - prevValue; // What's the overall gap?
    if (step) {                      // If its non-zero, 
        step = 1020/step;            //   divide by 1020
    }
    
    return step;
}

/* The next function is calculateVal. When the loop value, i,
*  reaches the step size appropriate for one of the
*  colors, it increases or decreases the value of that color by 1. 
*  (R, G, and B are each calculated separately.)
*/
int calculateVal(int step, int val, int i) {
    if ((step) && i % step == 0) { // If step is non-zero and its time to change a value,
        if (step > 0) {              //   increment the value if step is positive...
            val += 1;
        }
        else if (step < 0) {         //   ...or decrement it if step is negative
            val -= 1;
        }
    }
    
    // Defensive driving: make sure val stays in the range 0-255
    if (val > 255) {
        val = 255;
    }
    else if (val < 0) {
        val = 0;
    }
    
    return val;
}