ESP32 WIFI : tiwinkle inner LED when slaves serial read

Projects Programming
1

HI,
I'm doing a 1:N Wi-Fi test with a few ESP32, and the purpose of the test is serial.write() when a certain pin on the master is activated. (but now code are just writing Serial.)Then, as the slave parses the that Serial, the built-in LED must blink.

What's the problem?

master's code

#include <esp_now.h>
#include <WiFi.h>

// REPLACE WITH YOUR ESP RECEIVER'S MAC ADDRESS
//uint8_t broadcastAddress1[] = {0x40, 0x91, 0x51, 0x9A, 0xEB, 0xEC};
//uint8_t broadcastAddress2[] = {0x40, 0x91, 0x51, 0x9A, 0xE5, 0x94};
uint8_t Receiver_Address1[] = {0x40, 0x91, 0x51, 0x9A, 0xEB, 0xEC};
uint8_t Receiver_Address2[] = {0x40, 0x91, 0x51, 0x9A, 0xE5, 0x94};
uint8_t Receiver_Address3[] = {0x84, 0xCC, 0xA8, 0x5E, 0x52, 0x44};

typedef struct struct_message {
  int integer;
  char character[100];
} struct_message;

struct_message message;

void data_sent(const uint8_t *mac_addr, esp_now_send_status_t status) {
  char address[18];
  Serial.print("Sent to: ");
  snprintf(address, sizeof(address), "%02x:%02x:%02x:%02x:%02x:%02x",
           mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
  Serial.print(address);
  Serial.print(" status:\t");
  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
 
void setup() {
  Serial.begin(115200);
 
  WiFi.mode(WIFI_STA);
 
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }
  
  esp_now_register_send_cb(data_sent);
   
  esp_now_peer_info_t peerInfo;
  peerInfo.channel = 0;  
  peerInfo.encrypt = false;
  
  memcpy(peerInfo.peer_addr, Receiver_Address1, 6);
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Failed to add peer");
    return;
  }

  memcpy(peerInfo.peer_addr, Receiver_Address2, 6);
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Failed to add peer");
    return;
  }

  memcpy(peerInfo.peer_addr, Receiver_Address3, 6);
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Failed to add peer");
    return;
  }
}
 
void loop() {
  message.integer = Serial.write(0x61);
 strcpy(message.character, "Welcome to Microcontrollerslab! This is test example.");
 
  esp_err_t outcome = esp_now_send(0, (uint8_t *) &message, sizeof(struct_message));
   
  if (outcome == ESP_OK) {
    Serial.println("Sent with success");
  }
  else {
    Serial.println("Error sending the data");
  }
  delay(2000);
}

slave's code

#include <esp_now.h>
#include <WiFi.h>

//Must match the sender structure
typedef struct struct_message {
  int integer;
  char character[100];
} struct_message;

struct_message message;


void data_receive(const uint8_t * mac, const uint8_t *incomingData, int len) {
  memcpy(&message, incomingData, sizeof(message));
  Serial.print("Bytes received: ");

}

void setup() {

  Serial.begin(115200);
  WiFi.mode(WIFI_STA);

  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }

  esp_now_register_recv_cb(data_receive);
}

void loop() {
  //if (n != 0)
  //{
  //byte l = Serial.read();     //expecying numerical value; so, declare byte type variable
  byte p = Serial.available();  //check that a charcater/data byte has come from UNO

  if (p != 0)
  {
    byte l = Serial.read();     //expecying numerical value; so, declare byte type variable
    if ( l == 0x61
       )
      digitalWrite(2, HIGH);
    delay(1000);
    digitalWrite(2, LOW);
    delay(500);
    digitalWrite(2, HIGH);
    delay(500);
    digitalWrite(2, LOW);

  }
}

refer entirely to this reference. below.

thanks!

2

What output do you actually get? What output did you expect?