upload the esp32 p2p communication code

Code/ESP32_communication/simple_test/ESP32_master/ESP32_master.ino

+//-----------------------------------------------------------
+//ESP-NOW: Transmitter
+//Ref: Random Nerd Tutorials https://randomnerdtutorials.com
+//-----------------------------------------------------------
+#include <esp_now.h>
+#include <WiFi.h>
+//-------------------------------------------------------------------------------------
+uint8_t RxMACaddress[] = {0xC4, 0xDD, 0x57, 0x9E, 0x91, 0x74};
+String strdata = "";
+//-------------------------------------------------------------------------------------
+typedef struct TxStruct
+{
+  int potVal;
+}TxStruct;
+TxStruct sentData;
+//-------------------------------------------------------------------------------------
+void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) //callback function
+{
+  Serial.print("\r\nLast Packet Send Status:\t");
+  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
+}
+//======================================================================================
+void setup()
+{
+  Serial.begin(9600);
+  WiFi.mode(WIFI_STA);
+  //------------------------------------------------------------------------------------
+  if(esp_now_init() != ESP_OK)
+  {
+    Serial.println("Error initializing ESP-NOW");
+    return;
+  }
+  //-------------------------------------------------------------------------------------
+  esp_now_register_send_cb(OnDataSent);
+  //-------------------------------------------------------------------------------------
+  esp_now_peer_info_t peerInfo;
+  memcpy(peerInfo.peer_addr, RxMACaddress, 6);
+  peerInfo.channel = 0;  
+  peerInfo.encrypt = false;
+  //-------------------------------------------------------------------------------------
+  if(esp_now_add_peer(&peerInfo) != ESP_OK)
+  {
+    Serial.println("Failed to add peer");
+    return;
+  }
+}
+//======================================================================================
+void loop()
+{ 
+  while (Serial.available()>0){
+    int inChar = Serial.read();
+    /*
+    sentData.potVal = inChar - '0';
+    delay(10);
+    esp_now_send(RxMACaddress, (uint8_t *) &sentData, sizeof(sentData));
+    delay(500);
+    */
+   strdata += char(inChar);
+
+  if (inChar == '\n'){
+  sentData.potVal = strdata.toInt();
+  Serial.println(sentData.potVal);
+  esp_err_t result = esp_now_send(RxMACaddress, (uint8_t *) &sentData, sizeof(sentData));
+  //-------------------------------------------------------------------------------------
+  if (result == ESP_OK) Serial.println("Sent with success");
+  else Serial.println("Error sending the data");
+  //-------------------------------------------------------------------------------------
+  delay(500);
+  strdata = "";
+  }
+  
+  }
+
+  //-------------------------------------------------------------------------------------
+  
+}
+
+
+/*
+ * String inString = "";    // string to hold input
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+  // send an intro:
+  Serial.println("\n\nString toInt():");
+  Serial.println();
+}
+
+void loop() {
+  // Read serial input:
+  while (Serial.available() > 0) {
+    int inChar = Serial.read();
+    if (isDigit(inChar)) {
+      // convert the incoming byte to a char and add it to the string:
+      inString += (char)inChar;
+    }
+    // if you get a newline, print the string, then the string's value:
+    if (inChar == '\n') {
+      Serial.print("Value:");
+      Serial.println(inString.toInt());
+      Serial.print("String: ");
+      Serial.println(inString);
+      // clear the string for new input:
+      inString = "";
+    }
+  }
+}
+
+ * /
+ */

Code/ESP32_communication/simple_test/ESP32_slave/ESP32_slave.ino

+//ESP-NOW: Receiver
+//Ref: Random Nerd Tutorials https://randomnerdtutorials.com
+//-----------------------------------------------------------
+#include <esp_now.h>
+#include <WiFi.h>
+#include <Wire.h>
+
+//-------------------------------------------------------------------------------------
+
+//-------------------------------------------------------------------------------------
+typedef struct RxStruct
+{
+  int potVal;
+}RxStruct;
+RxStruct receivedData;
+//-------------------------------------------------------------------------------------
+void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len)
+{
+  memcpy(&receivedData, incomingData, sizeof(receivedData));
+  Serial.println(receivedData.potVal);
+}
+//======================================================================================
+void setup()
+{
+  Serial.begin(11520);
+  
+  WiFi.mode(WIFI_STA);
+  if (esp_now_init() != ESP_OK)
+  {
+    Serial.println("Error initializing ESP-NOW");
+    return;
+  }
+  esp_now_register_recv_cb(OnDataRecv);
+}
+//======================================================================================
+void loop()
+{
+
+}