ESP8266 Community Forum

- Wed Jul 06, 2016 5:27 am #50288 Hi,
One ESP client and other one server
Server send back what it receives from client
Server :

Code: Select all/* Udp Server
 * Send back what it receive from client
 */


#include <ESP8266WiFi.h>
#include <WiFiUdp.h>


WiFiUDP Udp;
char packetBuffer[128];
unsigned int localPort = 9999;
const char *ssid = "ESP8266 Thing";
const char *password = "xxxxxxxxx";
bool tickerOccured;


void setup() {
  Serial.begin(115200);
  WiFi.softAP(ssid, password);
  Udp.begin(localPort);
  }

void loop() {
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    int len = Udp.read(packetBuffer, 255);
    if (len > 0) packetBuffer[len-1] = 0;
    Serial.print("Received : ");   
    Serial.println(packetBuffer);
   
    Udp.beginPacket(Udp.remoteIP(),Udp.remotePort());
    Udp.write(packetBuffer);
    Udp.write("\r\n");
    Udp.endPacket();
     }
}

Client :

Code: Select all// udp client

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <SoftwareSerial.h>
#include <Ticker.h>
Ticker ticker;
WiFiUDP Udp;
const char *ssid = "ESP8266 Thing";
const char *password = "nardino26";
bool tickerOccured = false;
char packetBuffer[255];
unsigned int localPort = 9999;
IPAddress ipServer(192, 168, 4, 1);
IPAddress ipClient(192, 168, 4, 10);
IPAddress Subnet(255, 255, 255, 0);

void ticker_handler(){
  tickerOccured = true;
}


void setup() {
  Serial.begin(115200);
  ticker.attach(1, ticker_handler);
  WiFi.begin(ssid, password);
  WiFi.mode(WIFI_STA); // STA important !!!
  WiFi.config(ipClient, ipServer, Subnet);
  Udp.begin(localPort);
  delay(200);
}

void loop() {
 
//**************** Send to server**********************************************************
    Udp.beginPacket(ipServer,9999);
    char sbuf[128];
    unsigned long testID = millis();
    sprintf(sbuf, "%lu", testID);   
    Udp.write(sbuf);
    Udp.write("\r\n");
    Udp.endPacket();
    Serial.print("S : ");Serial.println(sbuf);
delay(70);
 
//***************** Receive from server ****************************************************
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    int len = Udp.read(packetBuffer, 255);
    if (len > 0) packetBuffer[len-1] = 0;
    Serial.print("R : ");   
    Serial.println(packetBuffer);
  }
Serial.println();
if (tickerOccured) {
  Serial.println ("ticker occured"); // Testing ticker
  tickerOccured = false;
}

delay(2);
}

Salutations

- Wed Jul 06, 2016 11:07 am #50312 If you want to send something like NMEA (as a broadcast,) then check this out.

https://www.hackster.io/rayburne/tardis-time-esp8266-ap-webserver-gps

In fact, multiple clients can connect to the AP and come on/off at will. I've had 3 clients running at once with no issues: One PC and 2 ESP8266's.

Ray

- Wed Jul 06, 2016 4:58 pm #50324

In fact, multiple clients can connect to the AP and come on/off at will. I've had 3 clients running at once with no issues: One PC and 2 ESP8266's.

I currently have 1 AP connected to Win 7 machine (192.168.4.1) & 2 clients running but the data sent from the clients is mixed in together like this:

Received from client (IP/Size/Data): 192.168.4.3 / 21 / Send millis: 780727

Connected: 0.0.0.0 192.168.4.1

Received from client (IP/Size/Data): 192.168.4.3 / 21 / Send millis: 782728

Connected: 0.0.0.0 192.168.4.1

Received from client (IP/Size/Data): 192.168.4.2 / 21 / Sending temp: 25.50

Connected: 0.0.0.0 192.168.4.1

Received from client (IP/Size/Data): 192.168.4.2 / 21 / Sending temp: 25.60

Connected: 0.0.0.0 192.168.4.1

Is there a way to separate each client into its own separate data stream?

thanks

- Thu Jul 07, 2016 9:52 am #50349

Is there a way to separate each client into its own separate data stream?

Just thinking out loud...
Would not the IP address of the connection provide the ability to make the distinction?

Ray