I am working on sending data from multiple clients to a server, all of which are NodeMCUs. I have been able to send data for a single iteration. Trouble arises when I want it to send data repeatedly so that if I update my client data, this new data should be reflected at the server as well.
Since I am using multiple clients, I have employed MAC addresses as the means of identifying the clients. This way, the signals received from a particular client are given as output to a particular pin.
To send data perpetually, I tried to use an infinite loop: while(true), but it reads the first connected client even on recognizing the second client.
Here's my server code:
#include <ESP8266WiFi.h>
#define Max_Clients 5
extern "C" {
#include <user_interface.h>
}
WiFiServer server(80); //Initialize the server on Port 80
WiFiClient *clients[Max_Clients] = {NULL}; //Initializing client(s)
String inputs [Max_Clients] ={""}; //Initializing to store the string received from clients
int32_t freq = 10000;
IPAddress remoteIP();
void setup() {
pinMode(D1,OUTPUT); //Intializing pins for showing output and input
pinMode(D2,OUTPUT);
pinMode(D3,OUTPUT);
pinMode(A0,INPUT);
Serial.begin(9600); //Start communication between the ESP8266-12E and the monitor window
analogWriteFreq(freq);
WiFi.mode(WIFI_AP); //This ESP8266-12E is an AccessPoint
WiFi.softAP("NodeMCU_js", "12345678"); //Provide the (SSID, password)
IPAddress myIP = WiFi.softAPIP(); //Obtain the IP of the Server
Serial.println("Server IP is: "); //Print the IP to the monitor window
Serial.println(myIP);
server.begin(); //Start the HTTP Server
}
void loop() {
WiFiClient client = server.available(); //Check if a new Client has connected to the server
unsigned char number_client;
struct station_info *stat_info;
struct ip_addr *IPaddress;
IPAddress address;
int k=0;
if (client) {
Serial.println("A new Client has connected :)");
for (int i=0 ; i<Max_Clients ; ++i){ //Acknowledges and sets up new clients
if (NULL == clients[i]){
Serial.println(i);
clients[i] = new WiFiClient(client); //nothing in clients[i] means it is a new client
break;
}
}
while (true){
delay(3000);
number_client = wifi_softap_get_station_num();
stat_info = wifi_softap_get_station_info();
Serial.println();
Serial.print("Total connected clients are = ");
Serial.print(number_client);
Serial.println();
while (stat_info != NULL){
for(int i=0 ; i<number_client ; ++i) { //For available clients
if (NULL != clients[i]) {
IPaddress = &stat_info->ip;
address = IPaddress->addr;
Serial.println();
Serial.print("Client = ");
Serial.print(i+1);
Serial.println();
Serial.print("Client IP Address = ");
Serial.print(address);
Serial.println();
Serial.print("Client MAC Address = ");
Serial.print(stat_info->bssid[0],HEX);
Serial.print(":");
Serial.print(stat_info->bssid[1],HEX);
Serial.print(":");
Serial.print(stat_info->bssid[2],HEX);
Serial.print(":");
Serial.print(stat_info->bssid[3],HEX);
Serial.print(":");
Serial.print(stat_info->bssid[4],HEX);
Serial.print(":");
Serial.print(stat_info->bssid[5],HEX);
Serial.println();
if (stat_info->bssid[0] == 0xDC && stat_info->bssid[1] == 0x4F && stat_info->bssid[2] == 0x22 && stat_info->bssid[3] == 0x17 && stat_info->bssid[4] == 0xEE && stat_info->bssid[5] == 0x95) {
Serial.println("Compared MAC address successfully - 1 :)");
String request1 = clients[i]->readStringUntil('\r');
Serial.print("Client 1 asks: ");
Serial.print(request1);
inputs[i] = request1;
int duty1 = request1.toInt();
analogWrite(D1,duty1);
clients[i]->flush();
k++;
clients[i]->print("From Central Server to Client 1 - 150\r");
}
if (stat_info->bssid[0] == 0xDC && stat_info->bssid[1] == 0x4F && stat_info->bssid[2] == 0x22 && stat_info->bssid[3] == 0x18 && stat_info->bssid[4] == 0x1F && stat_info->bssid[5] == 0x9D) {
Serial.println("Compared MAC address successfully - 2 :)");
String request2 = clients[i]->readStringUntil('\r');
Serial.print("Client 2 asks: ");
Serial.print(request2);
inputs[i] = request2;
int duty2 = request2.toInt();
analogWrite(D2,duty2);
clients[i]->flush();
clients[i]->print("From Central Server to Client 2 - 200\r");
k++;
}
if (stat_info->bssid[0] == 0xDC && stat_info->bssid[1] == 0x4F && stat_info->bssid[2] == 0x22 && stat_info->bssid[3] == 0x18 && stat_info->bssid[4] == 0xB && stat_info->bssid[5] == 0x71) {
Serial.println("Compared MAC address successfully - 3 :)");
String request3 = clients[i]->readStringUntil('\r');
Serial.print("Client 3 asks: ");
Serial.print(request3);
inputs[i] = request3;
int duty3 = request3.toInt();
analogWrite(D3,duty3);
clients[i]->flush();
k++;
clients[i]->print("From Central Server to Client 3 - 250\r");
}
if (k == 0){
Serial.println();
Serial.println("Client not recognised.");
}
stat_info = STAILQ_NEXT(stat_info, next);
Serial.println();
}
}
}
}
}
} //void loop closure
Here's my client code:
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
char ssid[] = "NodeMCU_js";
char password[] = "12345678";
WiFiClient client; // Creates a client that can connect to to a specified internet IP address and port as defined in client.connect()
IPAddress server(192,168,4,1);
void setup() {
pinMode(A0,INPUT);
pinMode(D6,OUTPUT);
WiFi.persistent(false);
WiFi.mode(WIFI_STA);
Serial.begin(9600); //Serial connection
WiFi.begin(ssid,password); //WiFi connection
while (WiFi.status() != WL_CONNECTED) { //Wait for the WiFI connection completion
delay(500);
Serial.println("Connecting...");
}
Serial.println("Connected.");
client.connect(server, 80); // Connection to the server
}
void loop() {
if(WiFi.status() == WL_CONNECTED){ //Check WiFi connection status
while(true){
int duty = analogRead(A0);
client.print(String(duty)+"\r"); //Client's message to the server
String answer = client.readStringUntil('\r'); //Reading response from the server
Serial.print("Central Server: 200"); //Printing the response
Serial.print(answer);
}
} else {
Serial.println("Error in WiFi connection");
}
}
Kindly suggest a solution. Thanks in advance.
