ESP32_Relay_X4_Modbus_v1.3

Product Description

This is a 4-relay board, having 4 binary inputs and an RS485 interface based on ESP32. The inputs are optoisolated (mine came with TLP785GB with 4.7k resistors on inputs, making it safe to operate them around max 24V), with a common ground, independent from the board’s main ground. The RS485 transceiver is a SP3485E. Connectors are detachable.

Manufacturer documentation

I bought it from AliExpress.

Product Images

GPIO Pinout

According to Tasmota discussion:

Function / Signal	ESP32 GPIO	ESP32 QFN Pin	Direction	Connected Hardware / Notes
RS485 TX	GPIO19	Pin 31	Output	UART TX -> SP3485 DI
RS485 RX	GPIO18	Pin 30	Input	UART RX <- SP3485 RO
RS485 Driver Enable	GPIO32	Pin 8	Output	SP3485 DE
RS485 Receiver Enable	GPIO32	Pin 8	Output	SP3485 RE (active LOW)
Relay 1	GPIO23	Pin 37	Output	Relay output 1
Relay 2	GPIO5	Pin 29	Output	Relay output 2
Relay 3	GPIO4	Pin 26	Output	Relay output 3
Relay 4	GPIO13	Pin 15	Output	Relay output 4
Digital Input 1	GPIO25	Pin 10	Input	IN1
Digital Input 2	GPIO26	Pin 11	Input	IN2
Digital Input 3	GPIO27	Pin 12	Input	IN3
Digital Input 4	GPIO33	Pin 9	Input	IN4
Status LED	GPIO15	Pin 23	Output	Usually inverted
PAD_TX2	GPIO17	Pin 28	..	no PSRAM
PAD_RX2	GPIO16	Pin 27	..	no PSRAM
PDAD_G12	GPIO12	..	..	..
PDAD_G14	GPIO14	..	..	..
PDAD_G21	GPIO21	..	..	..
PDAD_G22	GPIO22	..	..	..

All pins are inverted. It also exposes GPIOs 12, 14, 21, 22 labeled appropriately on the board.

Basic Config

https://github.com/esphome/devices.esphome.io/blob/main/src/docs/devices/ESP32_Relay_X4_Modbus_v1.3/config.yaml

substitutions:
  device_name: esp32-relay-x4_modbus-v1-3

esphome:
  name: ${device_name}

esp32:
  variant: esp32
  framework:
    type: esp-idf

logger:
  baud_rate: 0

sensor:
  - platform: uptime
    name: Uptime

button:
  - platform: restart
    name: Reboot
  - platform: safe_mode
    name: Reboot in safe mode

# ==========================
# RELAYS (OUTPUTS)
# ==========================
switch:
  - platform: gpio
    pin:
      number: 23
      inverted: true
    name: "Relay 1"

  - platform: gpio
    pin:
      number: 5
      inverted: true
      ignore_strapping_warning: true
    name: "Relay 2"

  - platform: gpio
    pin:
      number: 4
      inverted: true
    name: "Relay 3"

  - platform: gpio
    pin:
      number: 13
      inverted: true
    name: "Relay 4"

# ==========================
# INPUTS (BINARY SENSORS)
# ==========================
binary_sensor:
  - platform: gpio
    pin:
      number: 25
      inverted: true
    name: "Input 1"

  - platform: gpio
    pin:
      number: 26
      inverted: true
    name: "Input 2"

  - platform: gpio
    pin:
      number: 27
      inverted: true
    name: "Input 3"

  - platform: gpio
    pin:
      number: 33
      inverted: true
    name: "Input 4"

  # ==========================
  # EXTRA PADS (RX2/TX2)
  # ==========================
  - platform: gpio
    pin:
      number: 16
      inverted: true
      mode: INPUT_PULLUP
    name: "Pad RX2 as input"

  - platform: gpio
    pin:
      number: 17
      inverted: true
      mode: INPUT_PULLUP
    name: "Pad TX2 as input"

# ==========================
# RS485 (MODBUS) UART
# ==========================
uart:
  rx_pin: 18 # RS485 RX
  tx_pin: 19 # RS485 TX
  flow_control_pin: 32 # RS485 DE
  baud_rate: 9600

# ==========================
# Status LED (system state)
# ==========================
status_led:
  pin:
    number: 15
    inverted: true
    ignore_strapping_warning: true