ESP32 access point - arduino

Question

I have 2 ESP32 boards, and I want to make them server/client in Arduino IDE. Just two boards, no router in between.
So far I have followed tutorials, and I have been able to connect to the ESP32 from my phone.
#include <WiFi.h>
WiFiServer server;
const char *ssid = "Zupa";
const char *password = "12345678";
void setup() {
Serial.begin(115200);
Serial.println();
Serial.print("Configuring access point...");
WiFi.softAP(ssid, password);
IPAddress myIP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(myIP);
}
void loop() {
}
However, I cannot connect from other ESP32. Code as follows:
#include <WiFi.h>
#include <WiFiMulti.h>
WiFiMulti WiFiMulti;
void setup()
{
Serial.begin(115200);
delay(10);
enter code here
// We start by connecting to a WiFi network
WiFiMulti.addAP("Zupa", "12345678");
Serial.println();
Serial.println();
Serial.print("Wait for WiFi... ");
while(WiFiMulti.run() != WL_CONNECTED) {
Serial.print(".");
delay(500);
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
delay(500);
}
void loop()
{
const uint16_t port = 80;
const char * host = "192.168.1.4"; // ip
Serial.print("connecting to ");
Serial.println(host);
// Use WiFiClient class to create TCP connections
WiFiClient client;
if (!client.connect(host, port)) {
Serial.println("connection failed");
Serial.println("wait 5 sec...");
delay(5000);
return;
}
// This will send the request to the server
client.print("Send this data to server");
//read back one line from server
String line = client.readStringUntil('\r');
client.println(line);
Serial.println("closing connection");
client.stop();
Serial.println("wait 5 sec...");
delay(5000);
}
What happens is it just says it cannot connect. The IP address is default, and I double checked it on the server side! How come I can connect from phone and not from ESP32?
Furthermore, how would I communicate between the two? I tried reading online, but everyone seems to do phone to ESP communication, not ESP to ESP. I also tried reading Mr. Kolbans book on ESP32, but with no success. I am quite new at this, and feel stuck.

Answer 1

All I had to change was the WiFi library from the ESP8266wifi.h to the Wifi.h which is compatible with ESP32.
(Source)
From the code examples is just a matter of changing the code to fit your specific needs.

Answer 2

#include <WiFi.h>
#include <WiFiClient.h>
void setup()
{
Serial.begin(115200);
delay(10);
// We start by connecting to a WiFi network
WiFi.mode(WIFI_STA); //Set wifi mode as station
WiFi.begin("Zupa", "12345678");//Connect to other ESP32
Serial.println();
Serial.println();
Serial.print("Wait for WiFi... ");
//Wait for WiFi to connect
while(WiFi.waitForConnectResult() != WL_CONNECTED){
Serial.print(".");
delay(1000);
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
delay(500);
}
void loop()
{
const uint16_t port = 80;
const char * host = "192.168.1.4"; // ip
Serial.print("connecting to ");
Serial.println(host);
// Use WiFiClient class to create TCP connections
WiFiClient client;
if (!client.connect(host, port)) {
Serial.println("connection failed");
Serial.println("wait 5 sec...");
delay(5000);
return;
}
// This will send the request to the server
client.print("Send this data to server");
//read back one line from server
String line = client.readStringUntil('\r');
client.println(line);
Serial.println("closing connection");
client.stop();
Serial.println("wait 5 sec...");
delay(5000);
}

Answer 3

Try change the IP of client code to:
const char * host = "192.168.4.1"
Tip: I use the Finger app in Android or iOS to scan the network,
its very good to see the IP of each device connected.
(In your case, You need connect the mobile device into your Esp32's hot spot before use the Finger)