ESP32 Wireless Communication Protocols

The ESP32 supports several different wireless communication protocols. Each protocol has its advantages and disadvantages and one can be more suitable than the other depending on the application. This guide is a compilation of all our articles about wireless communication protocols with the ESP32.

Communication Protocols

In this article, we’ll cover the following communication protocols:

• BLE (Bluetooth Low Energy)
• Bluetooth Classic
• ESP-NOW
• Wi-Fi
• MQTT
• LoRa
• GSM/GPRS/LTE

We’ll keep this article updated as new tutorials are posted.

Bluetooth Low Energy (BLE)

Bluetooth Low Energy, BLE for short, is a power-conserving variant of Bluetooth. BLE’s primary application is short-distance transmission of small amounts of data (low bandwidth).

Unlike Bluetooth which is always on, BLE remains in sleep mode constantly except for when a connection is initiated. This makes it consume very low power. BLE consumes approximately 100x less power than Bluetooth (depending on the use case).

Additionally, BLE supports not only point-to-point communication, but also broadcast mode, and mesh network. Due to its properties, BLE is suitable for applications that need to exchange small amounts of data periodically running on a coin cell. For example, BLE is of great use in healthcare, fitness, tracking, beacons, security, and home automation industries.

• Low power consumption
• Short distance transmission
• Low bandwidth (small amounts of data)
• Ideal for exchanging small amounts of data periodically
• Supports point-to-point, broadcast, and mesh network

Learn how to get started with BLE on the ESP32 with our guides:

• Getting Started with ESP32 Bluetooth Low Energy (BLE) on Arduino IDE
• ESP32 BLE Server and Client (Bluetooth Low Energy)

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Bluetooth Classic

Bluetooth is a wireless technology standard used for exchanging data between fixed and mobile devices over short distances. It is optimized for continuous data streaming, while BLE is optimized for short burst data transmission. It consumes approximately x100 more power than BLE.

• Short distance transmission
• Optimized for continuous data streaming

Learn how to use Bluetooth Classic with the ESP32:

• ESP32 Bluetooth Classic with Arduino IDE – Getting Started

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ESP-NOW

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.

Stating the Espressif website, ESP-NOW is a “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 (…). 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.”

• Fast communication protocol
• Up to 250-byte payload can be carried
• Encrypted and unencrypted communication
• Range communication (220 meters in opan en field accordingly to our experiments)

Read our articles about ESP-NOW:

• Getting Started with ESP-NOW (ESP32 with Arduino IDE)
• ESP-NOW Two-Way Communication Between ESP32 Boards
• More ESP-NOW tutorials…

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Wi-Fi (client-server communication protocols)

HTTP Requests

You can exchange data between ESP32 boards using HTTP requests. One board acts as a server (Wi-Fi access point) and the other board acts as a client (Wi-Fi station).

Learn how to send data from one ESP32 board to the other using HTTP requests:

• ESP32 Client-Server Wi-Fi Communication Between Two Boards

The ESP32 can also make HTTP requests to third-party services on the internet to send or receive data. For that, the ESP32 needs to be connected to a Wi-Fi network with internet access.

• ESP32 HTTP GET and HTTP POST with Arduino IDE (JSON, URL Encoded, Text)

Server-Sent Events

Server-Sent Events (SSE) allow the client to receive automatic updates from a server via HTTP connection.

The client initiates the SSE connection and the server uses the event source protocol to send updates to the client. The client will receive updates from the server, but it can’t send any data to the server after the initial handshake.

Server-sent events are useful when you need to send new data to the server without the need for a request by the server, for example send sensor readings periodically or notifications.

Learn how to use server-sent events on an ESP32 web server:

• ESP32 Web Server using Server-Sent Events

WebSocket

A WebSocket is a persistent connection between a client and server that allows bidirectional communication between both parties using a TCP connection. This means you can send data from the client to the server and from the server to the client at any given time.

Get started with WebSocket protocol on the ESP32 by following the next tutorial:

• ESP32 WebSocket Server: Control Outputs (Arduino IDE)

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MQTT

MQTT stands for Message Queuing Telemetry Transport. It is a lightweight publish and subscribe system where you can publish and receive messages as a client. MQTT is a simple messaging protocol, designed for constrained devices with low-bandwidth.

To use MQTT to exchange data, you need an MQTT broker that is responsible for receiving all messages, filtering the messages, and publishing the message to all subscribed clients. MQTT is perfect for IoT projects with multiple devices.

Read our articles about the MQTT communication protocol with the ESP32.

• What is MQTT and How It Works
• ESP32 MQTT – Publish and Subscribe with Arduino IDE
• MicroPython – Getting Started with MQTT on ESP32/ESP8266

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LoRa

LoRa is a wireless data communication technology that uses a radio modulation technique that can be generated by Semtech LoRa transceiver chips.

LoRa allows long range communication of small amounts of data (which means a low bandwidth), and high immunity to interference while minimizing power consumption. So, it allows long distance communication with low power requirements.

• Long range communication
• Low bandwidth (small amounts of data)
• High immunity to interference
• Low power consumption

To use LoRa with the ESP32 boards, you need a LoRa transceiver chip. The word “transceiver” means that the chip can send and receive LoRa messages. There are ESP32 boards that already come with an on-board LoRa transceiver chip, which makes wiring much simpler.

Read our articles about LoRa communication:

• ESP32 with LoRa using Arduino IDE – Getting Started – learn what is LoRa, how to connect a LoRa chip to the ESP32, and exchange data between boards.
• TTGO LoRa32 SX1276 OLED Board: Getting Started with Arduino IDE – learn how to get started with LoRa with a board with a built-in LoRa chip and OLED display.
• ESP32 LoRa Sensor Monitoring with Web Server (Long Range Communication) – set up an ESP32 as a LoRa receiver and as a web server to display received readings.

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GSM/GPRS/LTE

You can connect your ESP32 board to a modem to be able to send and receive SMS and phone calls and connect to the internet using a SIM card as you would do with your smartphone. Some of those modems can also get GPS data like latitude, longitude, altitude, and date and time.

There are different modules available that are compatible with the ESP32 and there are also ESP32 boards that already come with a built-in modem and all the necessary circuitry.

We’ve experimented with the ESP32 SIM8000L (2G), and the ESP32 SIM7000G (3G and 4G), and we had pretty good results.

To get started with those boards, you can take a look at the following tutorials:

• Getting Started with LILYGO T-SIM7000G ESP32 (LTE, GPRS, and GPS)
• ESP32 Publish Data to Cloud without Wi-Fi (TTGO T-Call ESP32 SIM800L)
• ESP32 SIM800L: Send Text Messages (SMS Alert) with Sensor Readings
• Connect ESP32 to Cloud MQTT Broker (TTGO T-Call ESP32 SIM800L)

Wrapping Up

There are many different wireless communication protocols compatible with the ESP32 boards. This makes it one of the most versatile boards for IoT and Home Automation projects. In this article, we’ve covered LoRa, Bluetooth, Bluetooth Low Energy, ESP-NOW, Wi-Fi, MQTT, and GSM/GPRS/LTE.

If you want to learn more about those protocols with the EPS32, check out the corresponding links throughout the article.

We hope you found this useful.

Learn more about the ESP32 with our resources:

• Learn ESP32 with Arduino IDE
• Build Web Servers with ESP32 and ESP8266
• Firebase Web App with ESP32 and ESP826
• SMART HOME with Raspberry Pi, ESP32, and ESP8266

Thanks for reading.