Sonoff DUALR3

Development Board

Code name: SONOFF_DUALR3

ESP32

Sonoff DUALR3 is a development board based on the ESP32 microcontroller using XTENSA architecture.

This board features a maximum CPU frequency of 240 MHz and 4MB flash memory.

About Sonoff DUALR3

Smart relay switch with ESP32 - supports dual-channel control, power metering, and smart home automation.

Technical Specifications

Complete technical specification details for Sonoff DUALR3

Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 4.2

BLE 4.2

Microcontroller

Model esp32

Clock Speed 240 MHz

Flash Size 4MB

Architecture xtensa

✨ Features & Pins

Digital IO 40

Analog Input 16

PWM 19

Interrupts 16

Quick Setup

Copy-paste configs for Sonoff DUALR3 - auto‑generated from this board's exact hardware specs.

ESP32 240 MHz 4MB DIO Xtensa

In Arduino IDE 2 select Sonoff Dualr3 from the esp32 by Espressif package. In PlatformIO use board = esp32dev. ESP32 · 240 MHz · 4MB · DIO.

Tools menu settings

Board (select in Arduino IDE) Sonoff Dualr3

CPU Frequency 240 MHz

Flash Size 4MB

Flash Mode DIO

Upload Speed 921600

Architecture Xtensa

In Arduino IDE 2, open Boards Manager, search "esp32" by Espressif and install it. Then go to Tools → Board and select "Sonoff Dualr3" for the Sonoff DUALR3.

platformio.ini


[env:sonoff_dualr3]
platform  = espressif32
board     = esp32dev
framework = arduino

; Exact hardware config for Sonoff DUALR3
board_build.mcu        = esp32
board_build.f_cpu      = 240000000L
board_build.flash_size = 4MB
board_build.flash_mode = dio
board_upload.flash_size = 4MB

The board value is a close generic match - check PlatformIO board registry for an exact fit.

esp32: block (YAML)


esp32:
  board: esp32dev
  framework:
    type: arduino   # or "esp-idf"

# Sonoff DUALR3 - 240 MHz ESP32
# Flash: 4MB | USB: N/A

Paste into your device's .yaml. See ESPHome ESP32 docs for full options.

esptool.py - flash command


esptool.py \
  --chip esp32 \
  --baud 921600 \
  write_flash \
    --flash_mode dio \
    --flash_size 4MB \
    0x1000 bootloader.bin \
    0x8000    partitions.bin \
    0xe000    boot_app0.bin \
    0x10000   firmware.bin

Install: pip install esptool - replace firmware.bin with your binary - bootloader at 0x1000

Useful Links

Datasheets and resources for Sonoff DUALR3

ESP32 Datasheet

Microcontroller reference

Pin Mappings

Complete pinout and GPIO mapping for Sonoff DUALR3

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Touch	PWM	Other
0	A11	T1
1			PWM	TX
2	A12	T2	PWM
3			PWM	RX
4	A10	T0	PWM
5			PWM	SS
12	A15	T5	PWM
13	A14	T4	PWM
14	A16	T6	PWM
15	A13	T3	PWM
18			PWM	SCK
19			PWM	MISO
21			PWM	SDA
22			PWM	SCL
23			PWM	MOSI
25	A18		PWM	DAC1
26	A19		PWM	DAC2
27	A17	T7	PWM
32	A4	T9	PWM
33	A5	T8	PWM
34	A6
35	A7
36	A0
39	A3

Legend

A0 Analog input

T0 Touch sensor

PWM PWM capable

RX/TX Serial pins

LED Built-in LED

# Pin number

Default Tools & Configuration

Build and upload settings for Sonoff DUALR3

Setting	Value
Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	`0x1000`
Flash mode	dio
Boot mode	dio
Maximum upload size	1280 KB (1310720 bytes)
Maximum data size	320 KB (327680 bytes)