Code for the ESP32 Arduino based Stranger Things Christmas project, documented on https://hackaday.io/project/28603

stranger_things_wifi.ino

/*
 * USAGE:
 * After upload, will run a default sentence on APA102 string. To upload a new one, just send a new one from the serial line. 
 *
 * stranger_lights.ino - StrangerThings lights control - Version 1.0
 * Created on 12/2017
 *   by Enrico Sanino
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

 
#include <aREST.h>

#include <APA102.h>
#include <WiFi.h>
//#include "EEPROM.h"
#include <WiFiClient.h>
#include <WiFiServer.h>
#include <WiFiUdp.h>
#include <string.h>
#include <Preferences.h>
#include "SimpleBLE.h"


#define STRIP_SIZE 26
#define INPUT_BUFF_SIZE 64
#define ITERATIONS 10

// Define which pins to use.
SimpleBLE ble;
Preferences preferences;
//int addr = 0;
//#define EEPROM_SIZE 64
String beaconMsg = "Stranger Things V2.0";
String  value = "";
const uint8_t dataPin = 17;
const uint8_t clockPin = 4;
char wifiDataFlag = 0;
void wifiGetText(void);
char wifiDataAvailable(void);

const char* ssid     = "YOUR SSID";
const char* password = "YOUR PASSWORD";

char bufferLine[255]; //buffer to hold incoming packet

// Create an object for writing to the LED strip.
APA102<dataPin, clockPin> ledStrip;

int index1[STRIP_SIZE] = { 25, 24, 23, 22, 21, 20, 19, 18, 10, 11, 12, 13, 14, 15, 16, 17, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
char input_buffer[INPUT_BUFF_SIZE] = "merry christmas";
volatile int input_size = 15;
rgb_color colors[STRIP_SIZE];

WiFiServer server(80);

String ipToString(IPAddress ip){
  String s="";
  for (int i=0; i<4; i++)
    s += i  ? "." + String(ip[i]) : String(ip[i]);
  return s;
}

void setup() {
  pinMode(13, OUTPUT);
  preferences.begin("sthings", false);
  Serial.begin(115200);
  ledStrip.startFrame();
  Serial.print("a");
  for (int i = 0; i < STRIP_SIZE; i++) {
    colors[i] = rgb_color(0,0,0);
  }

  ledStrip.write(colors, STRIP_SIZE, 31);
  ledStrip.endFrame(STRIP_SIZE);

  Serial.println();
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);

    WiFi.begin(ssid, password);
    int cnt = 10;
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
        cnt--;
        if (cnt <= 0)
        {
          break;
        }
    }
    Serial.println("");
    Serial.println("WiFi connected.");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
   // sprintf(value, "%s", WiFi.localIP());
    //sprintf(value, "%x.%x.%x.%x", value[0], value[1], value[2], value[3]);
    value = ipToString(WiFi.localIP());
    Serial.println("VALORE    ");
    Serial.println(value);
    Serial.println("\VALORE    ");
    ble.begin(value);
    Serial.println("Gateway: ");
    Serial.println(WiFi.gatewayIP());
    
    server.begin();

    String tempStr = preferences.getString("sentence", "none");
    //String tempStrLen = preferences.getString("len", "none");
    tempStr.toCharArray(input_buffer, tempStr.length()+1);
    input_buffer[tempStr.length()+1] = '\0';
    preferences.end();
    Serial.println("Initial buffer: ");
    Serial.println(input_buffer);
    Serial.println(strlen(input_buffer));
    input_size = strlen(input_buffer);
    Serial.println(tempStr.length());
    Serial.println();
}

void loop(){

    wifiGetText();
  
  if (Serial.available() > 0) {
    input_size = Serial.available();
    Serial.readBytes(input_buffer, input_size);
    input_buffer[input_size] = '\0';
    Serial.print(input_buffer);
    Serial.print(" ");
    Serial.print(input_size+1);
    preferences.begin("sthings", false);
    preferences.remove("sentence");
    preferences.putString("sentence", input_buffer);
    preferences.end();
  }
  else if (wifiDataAvailable()) {
    input_size = strlen(bufferLine);
    strcpy(input_buffer, bufferLine);
    Serial.readBytes(input_buffer, input_size);
    input_buffer[input_size+1] = '\0';
    Serial.print(input_buffer);
    Serial.print(" ");
    Serial.print(input_size);
    preferences.begin("sthings", false);
    preferences.remove("sentence");
    preferences.putString("sentence", input_buffer);
    preferences.end();
  }
  
  ledStrip.startFrame();
  process(input_buffer, input_size);   
  ledStrip.endFrame(STRIP_SIZE);

  delay(500);
  for (int i = 0; i < STRIP_SIZE; i++) {
    colors[i] = rgb_color(64,64,64);
  }

  for (int i = 0; i < 31; i++) {
    ledStrip.startFrame();
    ledStrip.write(colors, STRIP_SIZE, i);
    ledStrip.endFrame(STRIP_SIZE);
    delay(10);
  }

  for (int i = 31; i >= 0; i--) {
    ledStrip.startFrame();
    ledStrip.write(colors, STRIP_SIZE, i);
    ledStrip.endFrame(STRIP_SIZE);
    delay(10);
  }

  for (int i = 0; i < STRIP_SIZE; i++) {
    colors[i] = rgb_color(0,0,0);
  }
  
  ledStrip.startFrame();
  ledStrip.write(colors, STRIP_SIZE, 31);
  ledStrip.endFrame(STRIP_SIZE);
  delay(500);
}



char wifiDataAvailable(void)
{
  char ret = 0;
  ret = wifiDataFlag;
  wifiDataFlag = 0;
  return ret;
}

void wifiGetText(void)
{
   WiFiClient client = server.available();   // listen for incoming clients
    if (client) 
    {                             // if you get a client,
    Serial.println("New Client.");           // print a message out the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) 
    {            // loop while the client's connected
      if (client.available()) 
      {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        if (c == '\n') 
        {                    // if the byte is a newline character

          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println();

            // the content of the HTTP response follows the header:
            client.print("<!DOCTYPE html>");
            client.print("<html>");
            client.print("<body>");
            client.print("<form action=\"/action_page.php\">");
            client.print("Text: <input type=\"text\" name=\"text\" value=\"Mickey\"><br>");
            client.print("<input type=\"submit\" value=\"Submit\">");
            client.print("</form>");
            client.print("</html>");
            client.print("</body>");
            // The HTTP response ends with another blank line:
            client.println();
            // break out of the while loop:
            break;
          } 
          else
          {    // if you got a newline, then clear currentLine:
            currentLine = "";
          }
        } 
        else if (c != '\r') 
        {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }

        if (currentLine.endsWith("HTTP/1.1")) 
        {
          int len = currentLine.length();

          for (int i = len; i > 0; i--)
          {
            if (currentLine[i] == '=')
            {
              i++;
              for (int j=0; j<255; j++)
              {
                bufferLine[j] = currentLine[i+j];
                if (currentLine.substring(i+j) == "HTTP/1.1")
                {
                  bufferLine[j] = '\0';
                  i = 0;
                  wifiDataFlag = 1;
                  break;
                }
              }
            }
          }
        }
      }
    }
    // close the connection:
    client.stop();
    Serial.println("Client Disconnected.");
   }
}