Hi, I am trying to program an Arduino board as server and another Arduino as client. They are going to communicate data with each other. Server requests data from client and in response client sends a string message to the server. Then, server analyses the message and responds to client.
The issue is that my client very unstably connects to server and mostly it fails to connect to server.
Codes are Attached (I used VS, so the functions are defined after the main body of the code).
// Client:
// This code designed to enable server and client board to communicate with each other
// by calling their name and exchanging messages over wifi
#include <Arduino.h>
#include <WiFi.h>
const char *ssid = "ESP32-Access-Point";
const char *password = "123456789";
unsigned long previousMillis = 0;
int interval = 500;
String CLIENT_NAME = "SENSOR1";
WiFiClient client;
// IP Address of the server
IPAddress server(192, 168, 4, 1);
String ServerMessage;
void setup()
{
Serial.begin(9600);
WiFi.begin(ssid, password);
Serial.println("Connecting");
while (WiFi.status() != WL_CONNECTED)
{
delay(50);
Serial.print(".");
Serial.println("");
Serial.print("Connected to WiFi network with IP Address: ");
Serial.println(WiFi.localIP());
}
}
void loop()
{
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval)
{
Serial.println("Attemting to connect");
// Check WiFi connection status
if (WiFi.status() == WL_CONNECTED)
{
Serial.println("wifi status connected");
client.connect(server, 80);
while (client.connected())
{
Serial.println("client connected");
String data = client.readStringUntil('\r');
if (data != "\0")
{
Serial.print("Received data from Server:");
Serial.println(data);
int Index = data.indexOf(':');
String CLIENT = data.substring(0, Index);
String ACTION = data.substring(Index + 1);
if (CLIENT == CLIENT_NAME)
{
if (ACTION == "TEMPERATURE?")
{
client.println("ACK:10");
Serial.println("This is Client: ACK10 was sent to server");
}
}
else if (CLIENT == "OUTPUT1")
{
if (ACTION == "ON" || ACTION == "OFF")
{
Serial.println("This is Client: server is sending output1 On or Off command");
}
}
client.flush();
data = "\0";
}
}
}
previousMillis = millis();
}
}
// Server:
// This code designed to enable server and client board to communicate with each other
// by calling their name and exchanging messages over wifi
#include <Arduino.h>
#include "WiFi.h"
#define NUM_CLIENTS 2
String data;
String CLIENT;
String ACTION;
const char *ssid = "ESP32-Access-Point";
const char *password = "123456789";
WiFiServer server(80);
WiFiClient *clients[NUM_CLIENTS] = {NULL};
void clientCommand(String input)
{
for (int i = 0; i < NUM_CLIENTS; i++)
{
WiFiClient client = server.available();
if (client)
{
if (client.connected())
{
client.println(input);
delay(10);
}
}
}
delay(100);
}
String clientRequest(String input)
{
String response = "\0";
for (int i = 0; i < NUM_CLIENTS; i++)
{
WiFiClient client = server.available();
client.setTimeout(100);
if (client)
{
if (client.connected())
{
client.println(input);
data = client.readStringUntil('\r'); // received the server's answer
if (data != "\0")
{
int Index = data.indexOf(':');
CLIENT = data.substring(0, Index);
ACTION = data.substring(Index + 1);
if (CLIENT == "ACK")
{
response = ACTION;
}
// ? Research to see if you can save a matrix of clients connected without needing to flush them
client.flush();
data = "\0";
}
}
}
}
delay(200);
return response;
}
void connect_wifi()
{
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(100);
}
}
void setup()
{
Serial.begin(9600);
//Start Server
Serial.println();
Serial.print("Setting soft AP (Access Point)…");
// Remove the password parameter, if you want the AP (Access Point) to be open
WiFi.mode(WIFI_AP);
WiFi.softAP(ssid, password);
IPAddress IP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(IP);
server.begin();
//End: Server
}
void loop()
{
if ((clientRequest("SENSOR1:TEMPERATURE?").toInt()) > 30) //Request the temperature from SENSOR1
{
clientCommand("OUTPUT1:ON"); //Sets the output on OUTPUT1
Serial.println("This is Server: Output1:On was sent to client");
}
else
{
clientCommand("OUTPUT1:OFF"); //Sets the output on OUTPUT1
Serial.println("This is Server: Output1:Off was sent to client");
}
delay(1000);
}
