Send Data Wirelessly Between ESP32 Using ESP-NOW

Introduction

ESP-NOW is yet another protocol developed by Espressif, which enables multiple devices to communicate with one another without using Wi-Fi. The protocol is similar to the low-power 2.4GHz wireless connectivity that is often deployed in wireless mouses. So, the pairing between devices is needed prior to their communication. After the pairing is done, the connection is safe and peer-to-peer, with no handshake being required.

Before proceed to the tutorial, please go through following tutorial first:

1. Dot Matrix Clock With NTP Server Using ESP32
2. Build Your Own Portable Contactless Temperature Reader

Video

This video shows how to send data wirelessly between 2 units of ESP32 board using ESP-NOW.

Hardware Preparation

This is the list of items used in the video.

• Node32 Lite
• 4 In 1 MAX7219 Dot Matrix Display Module

The custom PCB is created using CNC on Snapmaker. Below is the list of components used in the PCB.

• PCB PS 4x6inch
• Straight Pin Header (Male) 1x40 Ways
• 6x6x1 Push Button 4 Pin
• Transistor 2N2222
• Resistor 0.25W 5% (1K)
• 5V Piezo buzzer C/W wire

Schematic and PCB files

If you have Snapmaker, you can download - THIS FILES, and use it for CNC your PCB.

Sample Program

This is Arduino sample program. Before compile, please install following libraries through Library Manager:

• MD_MAX72XX by majicDesigns Version 3.2.1
• MD_Parola by majicDesigns Version 3.3.0
• TFT_eSPI by Bodmer Version 1.4.20
• MLX90614 Library by Adafruit Version 1.0.1

Thank You

References:

• ESP-Now Overview | Espressif Systems
• Getting Started with ESP-NOW (ESP32 with Arduino IDE)

Thanks for reading this tutorial. If you have any technical inquiries, please post at Cytron Technical Forum.

"Please be reminded, this tutorial is prepared for you to try and learn.
You are encouraged to improve the code for a better application."