I successfully transmit UDP packet from d1 mini to another d1 mini, however in serial monitor, I am seeing other random characters and numbers (:urn 1) I did not call for. What is this and how to avoid?
Code for Server Side
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#define WIFI_SSID "XXXX"
#define WIFI_PASS "XXXX"
// Set AP credentials
#define AP_SSID "XXXX"
#define AP_PASS "XXXX"
#define AP_CHANNEL 1
#define AP_HIDDEN true
#define AP_MAX_CON 8
// UDP
WiFiUDP UDP;
IPAddress local_IP(192,168,4,1);
IPAddress gateway(192,168,4,1);
IPAddress subnet(255,255,255,0);
#define UDP_PORT 4010
// UDP Buffer
char packetBuffer[UDP_TX_PACKET_MAX_SIZE];
ESP8266WebServer server(80);
/* Just a little test message. Go to http://192.168.4.1 in a web browser
connected to this access point to see it.
*/
void handleRoot() {
server.send(200, "text/html", "<h1>You are connected</h1>");
}
void setup() {
// Setup LED pin
pinMode(LED_BUILTIN, OUTPUT);
digitalWrite(LED_BUILTIN, LOW);
// Setup serial port
Serial.begin(115200);
Serial.println();
// Begin WiFi
WiFi.begin(WIFI_SSID, WIFI_PASS);
// Connecting to WiFi...
Serial.print("Connecting to ");
Serial.print(WIFI_SSID);
// Loop continuously while WiFi is not connected
while (WiFi.status() != WL_CONNECTED)
{
delay(100);
Serial.print(".");
}
// Connected to WiFi
Serial.println();
Serial.print("Connected! IP address: ");
Serial.println(WiFi.localIP());
// Begin Access Point
Serial.println("Starting access point...");
WiFi.softAPConfig(local_IP, gateway, subnet);
WiFi.softAP(AP_SSID, AP_PASS, AP_CHANNEL, AP_HIDDEN, AP_MAX_CON);
Serial.println(WiFi.localIP());
// Connected to WiFi
Serial.println();
Serial.println("Connected!");
Serial.print("IP address for network ");
Serial.print(WIFI_SSID);
Serial.print(" : ");
Serial.println(WiFi.localIP());
Serial.print("IP address for network ");
Serial.print(AP_SSID);
Serial.print(" : ");
Serial.print(WiFi.softAPIP());
Serial.print('\n');
// Begin listening to UDP port
UDP.begin(UDP_PORT);
Serial.print("Listening on UDP port ");
Serial.println(UDP_PORT);
//
server.on("/", handleRoot);
server.begin();
Serial.println("HTTP server started");
}
void loop() {
server.handleClient();
int packetSize = UDP.parsePacket();
int atm = UDP.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
Serial.println(atm);
digitalWrite(LED_BUILTIN,LOW);
if(packetSize && atm == 1)
{
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.println(atm);
digitalWrite(LED_BUILTIN,HIGH);
}
delay(1000);
}