Tiago ESP-NOW

ESP-01 onboard LED from a Button in an ESP8266 via ESP-NOW

ESP-NOW is a powerful communication protocol developed by Espressif that allows for direct communication between ESP devices without the need for Wi-Fi. This makes it an excellent choice for IoT applications where devices need to communicate directly without a central server or router. In this blog post, we will guide you through the process of lighting up the onboard LED of an ESP-01 from a button in an ESP8266 using ESP-NOW.

Materials Needed

  1. ESP-01 Module  (Affiliate) – https://s.click.aliexpress.com/e/_DETsfWR
  2. Wemos D1 Mini or similar (Affiliate) – https://s.click.aliexpress.com/e/_DD3JQhj
  3. Breadboard adapter for ESP-01 (Affiliate) – https://s.click.aliexpress.com/e/_DC3gXdN
  4. USB ESP-01 Programming Adapter with a CH340G chip (Affiliate) – https://s.click.aliexpress.com/e/_DETsfWR
  5. Breadboard and jumper wires (Affiliate) – https://s.click.aliexpress.com/e/_Dl5kuk1
  6. Push Button

Step 1: Setting Up the Hardware

First, connect the ESP-01 the Wemos D1 Mini  to the breadboard. Connect the push button to D5 pin of the Wemos D1 Mini . The other end of the button should be connected to the ground.

 

 

Step 2: Installing the ESP8266 Board Package

Before we start programming, we need to install the ESP8266 board package.

Step 3: Programming the D1 Mini (Sender)

We will program the ESP8266 NodeMCU send a signal to the ESP-01 when the button is pressed. To do this, we will use the ESP-NOW protocol. Here is a simple code snippet:

#include <ESP8266WiFi.h>
#include <espnow.h>

uint8_t remoteMac[] = { 0x48, 0x55, 0x19, 0x0C, 0x45, 0x96 };

//48:55:19:0C:45:96

const int buttonPin = D5;

void setup() {
  Serial.begin(115200);
  pinMode(buttonPin, INPUT);
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  esp_now_init();
  esp_now_set_self_role(ESP_NOW_ROLE_CONTROLLER);
  esp_now_add_peer(remoteMac, ESP_NOW_ROLE_SLAVE, 1, NULL, 0);
}

void loop() {
  if (digitalRead(buttonPin) == HIGH) {
    uint8_t dataToSend = 1;
    Serial.print("Data Sent:");
    Serial.println(dataToSend);
    esp_now_send(remoteMac, &dataToSend, sizeof(dataToSend));
    delay(10);
  } else {
    uint8_t dataToSend = 0;
    Serial.print("Data Sent:");
    Serial.println(dataToSend);
    esp_now_send(remoteMac, &dataToSend, sizeof(dataToSend));
    delay(10);
  }
}

 

Replace ESP-01_MAC_ADDRESS with the MAC address of your ESP-01 module.

 

Step 4: Programming the ESP-01 (Receiver)

 

#include <ESP8266WiFi.h>
#include <espnow.h>


void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  esp_now_init();
  esp_now_set_self_role(ESP_NOW_ROLE_SLAVE);
  esp_now_register_recv_cb(onDataReceived);
}

void loop() {
  // Nothing to do here, waiting for ESP-NOW messages
}

void onDataReceived(uint8_t *senderMac, uint8_t *data, uint8_t len) {
  if (*data == 1) 
  {
    digitalWrite(LED_BUILTIN, LOW);
    Serial.println("LED ON");
  }
  else if(*data == 0)
  {
    digitalWrite(LED_BUILTIN, HIGH);
    Serial.println("LED OFF");
}
}

 

Step 5: Testing the Setup

Now, upload the respective codes to the ESP8266 NodeMCU and the ESP-01. Press the button on the ESP8266 NodeMCU. The onboard LED of the ESP-01 should light up.

 

 

 

 

Conclusion

In this blog post, we have shown you how to use the ESP-NOW protocol to light up the onboard LED of an ESP-01 from a button in an ESP8266 NodeMCU. This is a simple yet powerful demonstration of how ESP-NOW can be used for direct communication between IoT devices. We hope you found this guide helpful and encourage you to experiment with ESP-NOW in your own projects.