Receiving data from a server using ESP8266 /Arduino Uno - automation

Question

I have a Raspberry Pi working as a WiFi hotspot and an Arduino Uno trying to get data from it using an ESP8266 module.
This is my receiver code for Arduino:
#include <SoftwareSerial.h>
#include <SerialESP8266wifi.h>
#define sw_serial_rx_pin 4 // Connect this pin to TX on the esp8266
#define sw_serial_tx_pin 6 // Connect this pin to RX on the esp8266
#define esp8266_reset_pin 5 // Connect this pin to CH_PD on the esp8266, not reset. (let reset be unconnected)
SoftwareSerial swSerial(sw_serial_rx_pin, sw_serial_tx_pin);
// the last parameter sets the local echo option for the ESP8266 module..
SerialESP8266wifi wifi(swSerial, swSerial, esp8266_reset_pin, Serial);//adding Serial enabled local echo and wifi debug
String inputString;
boolean stringComplete = false;
unsigned long nextPing = 0;
void setup() {
inputString.reserve(20);
swSerial.begin(9600);
Serial.begin(9600);
while (!Serial)
;
Serial.println("Starting wifi");
wifi.setTransportToTCP();// this is also default
// wifi.setTransportToUDP();//Will use UDP when connecting to server, default is TCP
wifi.endSendWithNewline(true); // Will end all transmissions with a newline and carriage return ie println.. default is true
wifi.begin();
wifi.connectToAP("RPi", "raspberry");
wifi.connectToServer("192.168.50.1", "1234");
wifi.send(SERVER, "ESP8266 test app started");
}
void loop() {
//Make sure the esp8266 is started..
if (!wifi.isStarted())
wifi.begin();
//Send what you typed in the arduino console to the server
static char buf[20];
if (stringComplete) {
inputString.toCharArray(buf, sizeof buf);
wifi.send(SERVER, buf);
inputString = "";
stringComplete = false;
}
//Send a ping once in a while..
if (millis() > nextPing) {
wifi.send(SERVER, "Ping ping..");
nextPing = millis() + 10000;
}
//Listen for incoming messages and echo back, will wait until a message is received, or max 6000ms..
WifiMessage in = wifi.listenForIncomingMessage(6000);
if (in.hasData) {
if (in.channel == SERVER)
Serial.println("Message from the server:");
else
Serial.println("Message a local client:");
Serial.println(in.message);
//Echo back;
wifi.send(in.channel, "Echo:", false);
wifi.send(in.channel, in.message);
nextPing = millis() + 10000;
}
//If you want do disconnect from the server use:
// wifi.disconnectFromServer();
}
//Listen for serial input from the console
void serialEvent() {
while (Serial.available()) {
char inChar = (char)Serial.read();
inputString += inChar;
if (inChar == '\n') {
stringComplete = true;
}
}
}
When I execute, the serial monitor shows:
OK ARFa C⸮C⸮j⸮H⸮AT+AWJAP="RPi",#raspberry" WIFI DISCONNECT WIFI
CONNECVED WIFI GOT IP
OK AT+CIFSR
+CIFSR:STAIP,"192.168.50.13"
+CIFQR:STAMAC,"2c:3a:eAT+CIPSTART=4,"TCP","192.0n8.50.1",121l
Link type ERROR
Raspberry Pi's ISC DHCP server:
wlan0: STA 2c:3a:e8:4e:bf:70 RADIUS: starting accounting session
5A3B2C85-000000E9 wlan0: STA 2c:3a:e8:4e:bf:70 WPA: pairwise key
handshake completed (RSN)
I also referred to this SO thread with no luck.

Answer 1

Some assumptions because you have not given the info:
Arduino IDE >=1.85
ESP8266 Community package >=2.41
ESP Module ESP8266-12E with latest AT firmware
if that is the case and these fragments (enclosed by X X) are no typos
+CIFQR:STAMAC,"2c:3a:eXAT+CIPSTART=4,"TCP","192.0XnX8.50.1",121l
this leaves the following points to check
hardware connectors - serial connectors between arduino and esp module
stable power source 3.3V for the ESP module
Sure this is ok - but just in case and as reference for other readers
serial speed - try to increase from 9600 to 57600 or even to 115200 baud
These pieces of code should be in the setup() and not in the loop()
//Make sure the esp8266 is started..
if (!wifi.isStarted())
wifi.begin();
//Send what you typed in the arduino console to the server
static char buf[20];
Code processing
nextPing = millis() + 10000;
at the end of
if (in.hasData) {
might lead to interuptions in the communication
Reason due to the processing of code this might trigger at an unwanted point