// --------------------------------------------------
//
// Code for control of ESP32 through MIT inventor app (Bluetooth).
// device used for tests: ESP32-WROOM-32D
//
// Written by mo thunderz (last update: 20.4.2021)
// https://www.youtube.com/watch?v=aM2ktMKAunw
//
// Edited for use with joysticks, multiple inputs, and all put together by: Nathan Witte
// Joystick Functionality based on tutorial by Tabletop Robotics
// https://www.youtube.com/watch?v=OnEg_IcMmg4
// rgb functionality added from example by: system?
// https://forum.arduino.cc/t/hue-controllable-rgb-led-lamp/8382
//
// --------------------------------------------------
// this header is needed for Bluetooth Serial -> works ONLY on ESP32
#include "BluetoothSerial.h"
// init Class:
BluetoothSerial ESP_BT;
// Parameters for Bluetooth interface
int incoming;
int dataIn[8] {0, 0, 0, 0, 0, 0, 0, 0};
int index_array = 0;
int counter = 0;
// init PINs: assign any pin on ESP32
int led_pin_1 = 5;
int led_pin_2 = 18;
int led_pin_3 = 19;
int redPin= 15;
int greenPin = 2;
int bluePin = 4;
float h;
int h_int;
int r=0, g=0, b=0;
int val=0;
void h2rgb(float h, int &R, int &G, int &B);
void setup() // run once, when the sketch starts
{
Serial.begin(9600);
ESP_BT.begin("ESP32_Control"); //Name of your Bluetooth interface -> will show up on your phone
pinMode (led_pin_1, OUTPUT);
pinMode (led_pin_2, OUTPUT);
pinMode (led_pin_3, OUTPUT);
pinMode(redPin, OUTPUT);
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
}
void loop() // run over and over again
{
if (ESP_BT.available())
{
incoming = ESP_BT.read(); //Read what we receive
if (incoming == 255) {
index_array = 0;
}
dataIn[index_array] = incoming;
index_array ++;
if (dataIn[1]){
digitalWrite(led_pin_1, dataIn[1]);
}
else{
digitalWrite(led_pin_1, LOW);
}
if (dataIn[2]){
digitalWrite(led_pin_2, dataIn[2]);
}
else{
digitalWrite(led_pin_2, LOW);
}
if (dataIn[3]){
digitalWrite(led_pin_3, dataIn[3]);
}
else{
digitalWrite(led_pin_3, LOW);
}
val= dataIn[5]*4; // Read the pin and display the value
//Serial.println(val);
h = ((float)val)/1024;
h_int = (int) 360*h;
h2rgb(h,r,g,b);
analogWrite(redPin, r);
analogWrite(greenPin, g);
analogWrite(bluePin, b);
}
}
void h2rgb(float H, int& R, int& G, int& B) {
int var_i;
float S=1, V=1, var_1, var_2, var_3, var_h, var_r, var_g, var_b;
if ( S == 0 ) //HSV values = 0 ÷ 1
{
R = V * 255;
G = V * 255;
B = V * 255;
}
else
{
var_h = H * 6;
if ( var_h == 6 ) var_h = 0; //H must be < 1
var_i = int( var_h ) ; //Or ... var_i = floor( var_h )
var_1 = V * ( 1 - S );
var_2 = V * ( 1 - S * ( var_h - var_i ) );
var_3 = V * ( 1 - S * ( 1 - ( var_h - var_i ) ) );
if ( var_i == 0 ) {
var_r = V ;
var_g = var_3 ;
var_b = var_1 ;
}
else if ( var_i == 1 ) {
var_r = var_2 ;
var_g = V ;
var_b = var_1 ;
}
else if ( var_i == 2 ) {
var_r = var_1 ;
var_g = V ;
var_b = var_3 ;
}
else if ( var_i == 3 ) {
var_r = var_1 ;
var_g = var_2 ;
var_b = V ;
}
else if ( var_i == 4 ) {
var_r = var_3 ;
var_g = var_1 ;
var_b = V ;
}
else {
var_r = V ;
var_g = var_1 ;
var_b = var_2 ;
}
R = (1-var_r) * 255; //RGB results = 0 ÷ 255
G = (1-var_g) * 255;
B = (1-var_b) * 255;
}
}
This link has the android app that accompanies this code
I'm confused 
- Just starting a topic and only showing code does not explain what you're trying to achieve with your topic. Are you just sharing? Or do you have a problem? Or asking for advice / improvements? Or ... ?
- Are you using a Classic Nano? Because you posted this in the Classic Nano section of the forum. Or is it about an ESP32 as in your title?
Sorry I was just using the forum as a way to post my code to share it with someone.
Great 
Is this about a classic Nano or about and ESP32? Or both?
If you give a little description of the project (and the 'protocol'), it might help others to understand.
I would add an additional check to make sure that you don't write outside the boundaries of dataIn; you do reset index_array when you receive a 255 but what happens if you don't receive that (for whatever reason).
The 255 is built into the app, it's just the way I wrote it. Not foolproof, but it works.
This is on the ESP32 and I send the data to a Nano via serial connection which I don't have in this code, because I added it later
Can you give a description of the data to complete this topic. I can basically get it from the code, others might not be able to.
Ya, so basically the app sends the joystick values, and buttons in a specific order before looping back to the value 255 which resets the receiving side. This allows a continuous flow of data from the app to the ESP32.