Help with ESP32 and ESP NOW example

Projects Programming
1

I’m struggling to find a simple example using esp now for one Esp32 board to send a message to another Esp32 board.

All the examples and tutorials that I have found don’t work for me and I get error messages.

The examples included in the ide seem over complicated and when I try to remove unnecessary code I just break it!
Any help would be greatly appreciated

2

That would indicate that the code you removed was in fact necessary.

3

DroneBotWorkShop.com does a great job of explaining ESP NOW (and everything he does). Wiring diagrams, sketches, and video, with descriptive narration.

4

Unfortunately his examples don’t work anymore, I think since the esp now update

5

Well, try these ones. They are a cut of sketches I’ve done after ESP changed from V2.x.x to V3.x.x (untested, since I’m far from my equipment).

Sender:

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

uint8_t broadcastAddress[] = {0x64, 0x06, 0x90, 0x64, 0x90, 0xF4}; //put here the MAC adress of the receiver ESP

typedef struct struct_message {
    int command;
} struct_message;

int counter=0;

struct_message myData;

esp_now_peer_info_t peerInfo;

void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {    //send data callback function
  Serial.print("I sent: ");
  Serial.println(myData.command);
}
 
void setup() {
 
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);

  if (esp_now_init() != ESP_OK) {
    Serial.println("Fail to initialize ESP-NOW");
    return;
  }

  esp_now_register_send_cb(esp_now_send_cb_t(OnDataSent));
  
  memcpy(peerInfo.peer_addr, broadcastAddress, 6);
  peerInfo.channel = 0;  
  peerInfo.encrypt = false;
         
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Fail to ad the receiver");
    return;
  }
}
 
void loop() {
   myData.command = counter++
   esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
   delay(2000);
}

Receiver

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

typedef struct struct_message {
    int command;
} struct_message;

struct_message myData;

 
// Callback function executed when data is received
void OnDataRecv(const uint8_t * mac, const uint8_t * incomingData, int len) {
  memcpy(&myData, incomingData, sizeof(myData));
}

 
void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  if (esp_now_init() != ESP_OK) {
    Serial.println("Fail to initialize ESP-NOW");
    return;
  }
  esp_now_register_recv_cb(esp_now_recv_cb_t(OnDataRecv));
  delay(1000);
}
 
void loop() {
  Serial.print("Data received:  ");
  Serial.println(myData.command);
}
6

Yes Brazilino, this is exactly it and wroks as i expected! thank you

7

You’re welcome. Happy to help. Have fun! :upside_down_face: