https://github.com/AlphaLima/ESP32-Serial-Bridge

ESP32-Serial-Bridge

Transparent WiFi (TCP) to all three UART Bridge, supports both AP and STATION WiFi modes. The .ino file is the code for the ESP32. Use Arduino IDE for ESP32 to compile and upload it to the ESP32. I made this project in order to connect Flight equipment devices devices like (Radio, Vario FLARM), to a Flight Computer (Kobo, Smartphones etc.), but it is not limited to that. You can use it wherever you want, but on your own risk. Read license file for more details. Accesspoint
IPAdress: 192.168.4.1
AP SSID: LK8000
AP Password: Flightcomputer
Used Ports:
192.168.4.1:8880 <-> COM0
192.168.4.1:8881 <-> COM1
192.168.4.1:8882 <-> COM2

===============================================================

Used Libraries: (must be installed in the arduino IDE):

https://github.com/espressif/arduino-esp32

===============================================================

In some cases the memorylayout is to small for this scetch. If you face this problem you can either disable Bluetooth by removing #define BLUETOOTH in config.h or change the partition size as described here: https://desire.giesecke.tk/index.php/2018/04/20/change-partition-size-arduino-ide/

Arduino hardware configuration:

===============================================================

example usecases:

https://www.youtube.com/watch?v=K2Hia06IMtk

https://www.youtube.com/watch?v=GoSxlQvuAhg

Hardware

here is the wiring diagram recomendation: https://raw.githubusercontent.com/AlphaLima/ESP32-Serial-Bridge/master/ESP32-SerialBridge.jpg

Pinning
COM0 Rx <-> GPIO21
COM0 Tx <-> GPIO01
COM1 Rx <-> GPIO16
COM1 Tx <-> GPIO17
COM2 Rx <-> GPIO15
COM2 Tx <-> GPIO04

NOTE: The PIN assignment has changed and may not look straigt forward (other PINs are marked as Rx/Tx), but this assignment allows to flash via USB also with hooked MAX3232 serial drivers.

I recomend to start your project with a Node32s or compatible evaluation board. For a TTL to RS232 level conversion search google for “TTL RS3232 Converter”

https://tech.scargill.net/wp-content/uploads/2017/05/ESP326.jpg

ESP32-Serial-Bridge-master


// ESP32 WiFi <-> 3x UART Bridge
// by AlphaLima
// www.LK8000.com

// Disclaimer: Don't use  for life support systems
// or any other situations where system failure may affect
// user or environmental safety.

#include "config.h"
#include <esp_wifi.h>
#include <WiFi.h>




#ifdef BLUETOOTH
#include <BluetoothSerial.h>
BluetoothSerial SerialBT; 
#endif

#ifdef OTA_HANDLER  
#include <ArduinoOTA.h> 

#endif // OTA_HANDLER

HardwareSerial Serial_one(1);
HardwareSerial Serial_two(2);
HardwareSerial* COM[NUM_COM] = {&Serial, &Serial_one , &Serial_two};

#define MAX_NMEA_CLIENTS 4
#ifdef PROTOCOL_TCP
#include <WiFiClient.h>
WiFiServer server_0(SERIAL0_TCP_PORT);
WiFiServer server_1(SERIAL1_TCP_PORT);
WiFiServer server_2(SERIAL2_TCP_PORT);
WiFiServer *server[NUM_COM]={&server_0,&server_1,&server_2};
WiFiClient TCPClient[NUM_COM][MAX_NMEA_CLIENTS];
#endif


uint8_t buf1[NUM_COM][bufferSize];
uint16_t i1[NUM_COM]={0,0,0};

uint8_t buf2[NUM_COM][bufferSize];
uint16_t i2[NUM_COM]={0,0,0};

uint8_t BTbuf[bufferSize];
uint16_t iBT =0;


void setup() {

  delay(500);
  
  COM[0]->begin(UART_BAUD0, SERIAL_PARAM0, SERIAL0_RXPIN, SERIAL0_TXPIN);
  COM[1]->begin(UART_BAUD1, SERIAL_PARAM1, SERIAL1_RXPIN, SERIAL1_TXPIN);
  COM[2]->begin(UART_BAUD2, SERIAL_PARAM2, SERIAL2_RXPIN, SERIAL2_TXPIN);
  
  if(debug) COM[DEBUG_COM]->println("\n\nLK8000 WiFi serial bridge V1.00");
  #ifdef MODE_AP 
   if(debug) COM[DEBUG_COM]->println("Open ESP Access Point mode");
  //AP mode (phone connects directly to ESP) (no router)
  WiFi.mode(WIFI_AP);
   
  WiFi.softAP(ssid, pw); // configure ssid and password for softAP
  delay(2000); // VERY IMPORTANT
  WiFi.softAPConfig(ip, ip, netmask); // configure ip address for softAP

  #endif


  #ifdef MODE_STA
   if(debug) COM[DEBUG_COM]->println("Open ESP Station mode");
  // STATION mode (ESP connects to router and gets an IP)
  // Assuming phone is also connected to that router
  // from RoboRemo you must connect to the IP of the ESP
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, pw);
  if(debug) COM[DEBUG_COM]->print("try to Connect to Wireless network: ");
  if(debug) COM[DEBUG_COM]->println(ssid);
  while (WiFi.status() != WL_CONNECTED) {   
    delay(500);
    if(debug) COM[DEBUG_COM]->print(".");
  }
  if(debug) COM[DEBUG_COM]->println("\nWiFi connected");
  
  #endif
#ifdef BLUETOOTH
  if(debug) COM[DEBUG_COM]->println("Open Bluetooth Server");  
  SerialBT.begin(ssid); //Bluetooth device name
 #endif
#ifdef OTA_HANDLER  
  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);
    })
    .onEnd([]() {
      Serial.println("\nEnd");
    })
    .onProgress([](unsigned int progress, unsigned int total) {
      Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
    })
    .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");
    });
  // if DNSServer is started with "*" for domain name, it will reply with
  // provided IP to all DNS request

  ArduinoOTA.begin();
#endif // OTA_HANDLER    

  #ifdef PROTOCOL_TCP
  COM[0]->println("Starting TCP Server 1");  
  if(debug) COM[DEBUG_COM]->println("Starting TCP Server 1");  
  server[0]->begin(); // start TCP server 
  server[0]->setNoDelay(true);
  COM[1]->println("Starting TCP Server 2");
  if(debug) COM[DEBUG_COM]->println("Starting TCP Server 2");  
  server[1]->begin(); // start TCP server 
  server[1]->setNoDelay(true);
  COM[2]->println("Starting TCP Server 3");
  if(debug) COM[DEBUG_COM]->println("Starting TCP Server 3");  
  server[2]->begin(); // start TCP server   
  server[2]->setNoDelay(true);
  #endif

  esp_err_t esp_wifi_set_max_tx_power(50);  //lower WiFi Power
}


void loop() 
{  
#ifdef OTA_HANDLER  
  ArduinoOTA.handle();
#endif // OTA_HANDLER
  
#ifdef BLUETOOTH
  // receive from Bluetooth:
  if(SerialBT.hasClient()) 
  {
    while(SerialBT.available())
    {
      BTbuf[iBT] = SerialBT.read(); // read char from client (LK8000 app)
      if(iBT <bufferSize-1) iBT++;
    }          
    for(int num= 0; num < NUM_COM ; num++)
      COM[num]->write(BTbuf,iBT); // now send to UART(num):          
    iBT = 0;
  }  
#endif  
#ifdef PROTOCOL_TCP
  for(int num= 0; num < NUM_COM ; num++)
  {
    if (server[num]->hasClient())
    {
      for(byte i = 0; i < MAX_NMEA_CLIENTS; i++){
        //find free/disconnected spot
        if (!TCPClient[num][i] || !TCPClient[num][i].connected()){
          if(TCPClient[num][i]) TCPClient[num][i].stop();
          TCPClient[num][i] = server[num]->available();
          if(debug) COM[DEBUG_COM]->print("New client for COM"); 
          if(debug) COM[DEBUG_COM]->print(num); 
          if(debug) COM[DEBUG_COM]->println(i);
          continue;
        }
      }
      //no free/disconnected spot so reject
      WiFiClient TmpserverClient = server[num]->available();
      TmpserverClient.stop();
    }
  }
#endif
 
  for(int num= 0; num < NUM_COM ; num++)
  {
    if(COM[num] != NULL)          
    {
      for(byte cln = 0; cln < MAX_NMEA_CLIENTS; cln++)
      {               
        if(TCPClient[num][cln]) 
        {
          while(TCPClient[num][cln].available())
          {
            buf1[num][i1[num]] = TCPClient[num][cln].read(); // read char from client (LK8000 app)
            if(i1[num]<bufferSize-1) i1[num]++;
          } 

          COM[num]->write(buf1[num], i1[num]); // now send to UART(num):
          i1[num] = 0;
        }
      }
  
      if(COM[num]->available())
      {
        while(COM[num]->available())
        {     
          buf2[num][i2[num]] = COM[num]->read(); // read char from UART(num)
          if(i2[num]<bufferSize-1) i2[num]++;
        }
        // now send to WiFi:
        for(byte cln = 0; cln < MAX_NMEA_CLIENTS; cln++)
        {   
          if(TCPClient[num][cln])                     
            TCPClient[num][cln].write(buf2[num], i2[num]);
        }
#ifdef BLUETOOTH        
        // now send to Bluetooth:
        if(SerialBT.hasClient())      
          SerialBT.write(buf2[num], i2[num]);               
#endif  
        i2[num] = 0;
      }
    }    
  }
}

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// ESP32 WiFi <-> 3x UART Bridge

// by AlphaLima

// www.LK8000.com

// Disclaimer: Don't use for life support systems

// or any other situations where system failure may affect

// user or environmental safety.

#include "config.h"

#include <esp_wifi.h>

#include <WiFi.h>

#ifdef BLUETOOTH

#include <BluetoothSerial.h>

BluetoothSerial SerialBT;

#endif

#ifdef OTA_HANDLER

#include <ArduinoOTA.h>

#endif // OTA_HANDLER

HardwareSerial Serial_one(1);

HardwareSerial Serial_two(2);

HardwareSerial* COM[NUM_COM] = {&Serial, &Serial_one , &Serial_two};

#define MAX_NMEA_CLIENTS 4

#ifdef PROTOCOL_TCP

#include <WiFiClient.h>

WiFiServer server_0(SERIAL0_TCP_PORT);

WiFiServer server_1(SERIAL1_TCP_PORT);

WiFiServer server_2(SERIAL2_TCP_PORT);

WiFiServer *server[NUM_COM]={&server_0,&server_1,&server_2};

WiFiClient TCPClient[NUM_COM][MAX_NMEA_CLIENTS];

#endif

uint8_t buf1[NUM_COM][bufferSize];

uint16_t i1[NUM_COM]={0,0,0};

uint8_t buf2[NUM_COM][bufferSize];

uint16_t i2[NUM_COM]={0,0,0};

uint8_t BTbuf[bufferSize];

uint16_t iBT =0;

void setup() {

delay(500);

COM[0]->begin(UART_BAUD0, SERIAL_PARAM0, SERIAL0_RXPIN, SERIAL0_TXPIN);

COM[1]->begin(UART_BAUD1, SERIAL_PARAM1, SERIAL1_RXPIN, SERIAL1_TXPIN);

COM[2]->begin(UART_BAUD2, SERIAL_PARAM2, SERIAL2_RXPIN, SERIAL2_TXPIN);

if(debug) COM[DEBUG_COM]->println("\n\nLK8000 WiFi serial bridge V1.00");

#ifdef MODE_AP

if(debug) COM[DEBUG_COM]->println("Open ESP Access Point mode");

//AP mode (phone connects directly to ESP) (no router)

WiFi.mode(WIFI_AP);

WiFi.softAP(ssid, pw); // configure ssid and password for softAP

delay(2000); // VERY IMPORTANT

WiFi.softAPConfig(ip, ip, netmask); // configure ip address for softAP

#endif

#ifdef MODE_STA

if(debug) COM[DEBUG_COM]->println("Open ESP Station mode");

// STATION mode (ESP connects to router and gets an IP)

// Assuming phone is also connected to that router

// from RoboRemo you must connect to the IP of the ESP

WiFi.mode(WIFI_STA);

WiFi.begin(ssid, pw);

if(debug) COM[DEBUG_COM]->print("try to Connect to Wireless network: ");

if(debug) COM[DEBUG_COM]->println(ssid);

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

delay(500);

if(debug) COM[DEBUG_COM]->print(".");

}

if(debug) COM[DEBUG_COM]->println("\nWiFi connected");

#endif

#ifdef BLUETOOTH

if(debug) COM[DEBUG_COM]->println("Open Bluetooth Server");

SerialBT.begin(ssid); //Bluetooth device name

#endif

#ifdef OTA_HANDLER

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);

})

.onEnd([]() {

Serial.println("\nEnd");

})

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

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

})

.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");

});

// if DNSServer is started with "*" for domain name, it will reply with

// provided IP to all DNS request

ArduinoOTA.begin();

#endif // OTA_HANDLER

#ifdef PROTOCOL_TCP

COM[0]->println("Starting TCP Server 1");

if(debug) COM[DEBUG_COM]->println("Starting TCP Server 1");

server[0]->begin(); // start TCP server

server[0]->setNoDelay(true);

COM[1]->println("Starting TCP Server 2");

if(debug) COM[DEBUG_COM]->println("Starting TCP Server 2");

server[1]->begin(); // start TCP server

server[1]->setNoDelay(true);

COM[2]->println("Starting TCP Server 3");

if(debug) COM[DEBUG_COM]->println("Starting TCP Server 3");

server[2]->begin(); // start TCP server

server[2]->setNoDelay(true);

#endif

esp_err_t esp_wifi_set_max_tx_power(50); //lower WiFi Power

}

void loop()

{

#ifdef OTA_HANDLER

ArduinoOTA.handle();

#endif // OTA_HANDLER

#ifdef BLUETOOTH

// receive from Bluetooth:

if(SerialBT.hasClient())

{

while(SerialBT.available())

{

BTbuf[iBT] = SerialBT.read(); // read char from client (LK8000 app)

if(iBT <bufferSize-1) iBT++;

}

for(int num= 0; num < NUM_COM ; num++)

COM[num]->write(BTbuf,iBT); // now send to UART(num):

iBT = 0;

}

#endif

#ifdef PROTOCOL_TCP

for(int num= 0; num < NUM_COM ; num++)

{

if (server[num]->hasClient())

{

for(byte i = 0; i < MAX_NMEA_CLIENTS; i++){

//find free/disconnected spot

if (!TCPClient[num][i] || !TCPClient[num][i].connected()){

if(TCPClient[num][i]) TCPClient[num][i].stop();

TCPClient[num][i] = server[num]->available();

if(debug) COM[DEBUG_COM]->print("New client for COM");

if(debug) COM[DEBUG_COM]->print(num);

if(debug) COM[DEBUG_COM]->println(i);

continue;

}

//no free/disconnected spot so reject

WiFiClient TmpserverClient = server[num]->available();

TmpserverClient.stop();

}

#endif

for(int num= 0; num < NUM_COM ; num++)

{

if(COM[num] != NULL)

{

for(byte cln = 0; cln < MAX_NMEA_CLIENTS; cln++)

{

if(TCPClient[num][cln])

{

while(TCPClient[num][cln].available())

{

buf1[num][i1[num]] = TCPClient[num][cln].read(); // read char from client (LK8000 app)

if(i1[num]<bufferSize-1) i1[num]++;

}

COM[num]->write(buf1[num], i1[num]); // now send to UART(num):

i1[num] = 0;

}

if(COM[num]->available())

{

while(COM[num]->available())

{

buf2[num][i2[num]] = COM[num]->read(); // read char from UART(num)

if(i2[num]<bufferSize-1) i2[num]++;

}

// now send to WiFi:

for(byte cln = 0; cln < MAX_NMEA_CLIENTS; cln++)

{

if(TCPClient[num][cln])

TCPClient[num][cln].write(buf2[num], i2[num]);

}

#ifdef BLUETOOTH

// now send to Bluetooth:

if(SerialBT.hasClient())

SerialBT.write(buf2[num], i2[num]);

#endif

i2[num] = 0;

}

ESP32-Serial-Bridge

Hardware

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