Voir la source de Getting Started with ESP-NOW

{{Tuto Details
|Main_Picture=Getting_Started_with_ESP-NOW_1.PNG
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|Description=<translate>Will guide you to communicate between ESP32 controllers by using ESP NOW protocol.</translate>
|Area=Electronics
|Type=Technique
|Difficulty=Easy
|Duration=1
|Duration-type=hour(s)
|Cost=10
|Currency=USD ($)
|Tags=ESP 32, ESP-NOW, Iot, Microcontrollers
}}
{{Introduction
|Introduction=<translate>ESP-NOW is a wireless communication protocol based on the data-link layer that enables the direct, quick, and low-power control of smart devices without the need for a router. Espressif defines it and can work with Wi-Fi and Bluetooth LE. ESP-NOW provides flexible and low-power data transmission to all interconnected devices. It can also be used as an independent protocol that helps with device provisioning, debugging, and firmware upgrades.

ESP-NOW is a connectionless communication protocol developed by Espressif that features short packet transmission. This protocol enables multiple devices to talk to each other in an easy way. It is a fast communication protocol that can be used to exchange small messages (up to 250 bytes) between ESP32 or ESP8266 boards. ESP-NOW supports the following features: Encrypted and unencrypted unicast communication; Mixed encrypted and unencrypted peer devices; Up to 250-byte payload can be carried; Sending callback function that can be set to inform the application layer of transmission success or failure.</translate>
}}
{{Materials
|Material=<translate></translate>
|Tools=<translate></translate>
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{{Tuto Step
|Step_Title=<translate>Get PCBs for Your Projects Manufactured</translate>
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You get 10 good-quality PCBs manufactured and shipped to your doorstep for cheap. You will also get a discount on shipping on your first order. Upload your Gerber files onto [https://www.pcbway.com/ PCBWAY] to get them manufactured with good quality and quick turnaround time. PCBWay now could provide a complete product solution, from design to enclosure production. Check out their online Gerber viewer function. With reward points, you can get free stuff from their gift shop.</translate>
|Step_Picture_00=Getting_Started_with_ESP-NOW_2.PNG
}}
{{Tuto Step
|Step_Title=<translate>How is it different from existing protocols?</translate>
|Step_Content=<translate>[https://www.theengineeringprojects.com/2022/01/esp-now-protocol-with-esp32-and-esp8266.html ESP-NOW] is a wireless communication protocol that is different from Wi-Fi and Bluetooth in that it reduces the five layers of the OSI model to only one1. Additionally, ESP-NOW occupies fewer CPU and flash resources than traditional connection protocols while co-exists with Wi-Fi and Bluetooth LE.

Bluetooth is used to connect short-range devices for sharing information, while Wi-Fi is used for providing high-speed internet access2. Wi-Fi provides high bandwidth because the speed of the internet is an important issue.

===Max Distance: ===
The range of ESP-NOW is up to 480 meters when using the ESP-NOW protocol for bridging between multiple ESP32s1. The range can be further increased by enabling long-range ESP-NOW. When enabled, the PHY rate of ESP32 will be 512Kbps or 256Kbps.

===Maximum nodes: ===
ESP-NOW supports various series of Espressif chips, providing a flexible data transmission that is suitable for connecting “one-to-many” and “many-to-many” devices.

===Applications: ===
ESP-NOW is widely used in

*smart-home appliances,
*remote controlling,
*sensors, etc.

In this tutorial, will see how to implement a basic ESP NOW communication between ESP32 Microcontrollers.</translate>
|Step_Picture_00=Getting_Started_with_ESP-NOW_3_-_Copy.PNG
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{{Tuto Step
|Step_Title=<translate>Setting Up the Receiver</translate>
|Step_Content=<translate>ESPNOW communication works based on the MAC address of the nodes. So, we need to find the Mac address of our slave or receiver node.

]For that just upload the following sketch to the ESP32 board and look for the Mac address in the serial monitor.<syntaxhighlight>
#include "WiFi.h"
 
void setup(){
  Serial.begin(115200);
  WiFi.mode(WIFI_MODE_STA);
  Serial.println(WiFi.macAddress());
}
 
void loop(){
}
</syntaxhighlight>


Once you uploaded the code, press the EN button and wait for the serial monitor results. It will show you the Mac address. Note that.</translate>
|Step_Picture_00=Getting_Started_with_ESP-NOW_4.PNG
|Step_Picture_01=Getting_Started_with_ESP-NOW_5.PNG
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{{Tuto Step
|Step_Title=<translate>Setting Up the Transmitter</translate>
|Step_Content=<translate>Next, we need to prepare the transmitter, for that use this example sketch which can send multiple data types of data to the particular slave node.<syntaxhighlight>
  
  // Register peer
  memcpy(peerInfo.peer_addr, broadcastAddress, 6);
  peerInfo.channel = 0;  
  peerInfo.encrypt = false;
  
  // Add peer        
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Failed to add peer");
    return;
  }
}
 
void loop() {
  // Set values to send
  strcpy(myData.a, "I'm alive");
  myData.b = random(1,20);
  myData.c = 1.2;
  myData.d = false;
  
  // Send message via ESP-NOW
  esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
   
  if (result == ESP_OK) {
    Serial.println("Sent with success");
  }
  else {
    Serial.println("Error sending the data");
  }
  delay(2000);
}
</syntaxhighlight><blockquote>Note: Change the Mac Address here</blockquote>Here are the serial monitor results, it show sent success but not delivered. Because we don't have the receiver.

Let's try to implement the receiver.</translate>
|Step_Picture_00=Getting_Started_with_ESP-NOW_6.PNG
}}
{{Tuto Step
|Step_Title=<translate>Testing the Connection</translate>
|Step_Content=<translate>With the help of below example sketch, you can receive the data from the master and it will print that into the serial monitor.<syntaxhighlight>
#include <esp_now.h>
#include <WiFi.h>

// Structure example to receive data
typedef struct struct_message {
    char a[32];
    int b;
    float c;
    bool d;
} struct_message;

// Create a struct_message called myData
struct_message myData;

// callback function that will be executed when data is received
void OnDataRecv(const uint8_t * mac, const uint8_t *incomingData, int len) {
  memcpy(&myData, incomingData, sizeof(myData));
  Serial.print("Bytes received: ");
  Serial.println(len);
  Serial.print("Char: ");
  Serial.println(myData.a);
  Serial.print("Int: ");
  Serial.println(myData.b);
  Serial.print("Float: ");
  Serial.println(myData.c);
  Serial.print("Bool: ");
  Serial.println(myData.d);
  Serial.println();
}
 
void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);
  
  // Set device as a Wi-Fi Station
  WiFi.mode(WIFI_STA);

  // Init ESP-NOW
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }
  
  // get recv packer info
  esp_now_register_recv_cb(OnDataRecv);
}
 
void loop() {

}
</syntaxhighlight>Serial monitor results.</translate>
|Step_Picture_00=Getting_Started_with_ESP-NOW_7.PNG
}}
{{Tuto Step
|Step_Title=<translate>Wrap Up:</translate>
|Step_Content=<translate><section id="story" data-origID="story" >
We have seen how to implement the ESP NOW in ESP32 microcontroller, in upcoming tutorials will see how to transmit sensor data via ESPNOW.
</section></translate>
}}
{{Notes
|Notes=<translate></translate>
}}
{{PageLang
|Language=en
|SourceLanguage=none
|IsTranslation=0
}}
{{Tuto Status
|Complete=Published
}}