ESP32 + relay + integrated 230V AC power supply + sensors

In a home automation installation, we often need at the local level a set including sensors such as:

• a presence detector,
• a measurement of brightness
• a temperature measurement

A relay as actuator

A microcontroller for processing

There are many relays on the market that can be controlled with their proprietary software, but it is difficult to add a sensor or sensor.

The modules presented here brings together an ESP32, 1 or 4 relays, and a power supply on the same board.

We find them at Aliexpress :

• 1 relay
• 4 relays

Benefits

• ESP32 grouping, relay and power supply. This simplifies the wiring
• Plate mounting holes
• GPIO or IO inputs/outputs to be wired below or above, which is very practical
• Numerous GND, 5V and 3.3V pins to connect sensors

Drawbacks

• No USB access for first programming. A USB/TTL interface is required

Hardware (1 relay board)

One power supply 230V AC

4 connectors * 10 pins

3V3	CLK	5V	GND
SD0	SD1	SD3	CMD
IO15	IO2	IO13	SD2
IO0	IO4	IO14	IO12
IO16	IO17	IO26	IO27
IO5	IO18	IO33	IO25
IO19	GND	IO35	IO32
IO21	RXD0	SVN	IO34
TXD0	IO22	EN	SVP
IO23	GND	GND	3V3

Programming Connector

IO0

GND

GND

RX

TX

5V

Others

Rely	IO16
LED blue	IO23
Button EN (Reset)	EN
Button IO0	IO0

Hardware (4 relays board)

3 possible power supply inputs :

• 230V AC
• 7V à 30V DC
• 5V DC

4 connectors * 10 pins

3V3	CLK	5V	GND
SD0	SD1	SD3	CMD
G15	G2	G13	SD2
G0	G4	G14	G12
G16	G17	G26 (relay)	G27
G5	G18	G33 (relay)	G25 (relay)
G19	GND	G35	G32 (relay)
G21	RXD	SVN	G34
TXD0	G22	EN	SVP
G23 (LED )	GND	GND	3V3

Programming

To download code, you need to connect a USB / TTL interface with the power strap on 3V3.

For powering the ESP32 card during programming, we have 2 choices:

• power through the serial adapter VCC output to the 5V of the ESP card (will only work for programming)
• supply the ESP32 with 230V and no serial link VCC output to ESP32 card

To start programming, you must:

• keep the IO0 button pressed
• press EN (Reset)
• release the 2 buttons

So the ESP waits for programming. After programming push again the EN button to reset and starts the new program.

Software

This module has the advantage of not being proprietary, you can put whatever you want there.

Arduino

With the Arduino IDE tool, you can develop your own code. Choose the ESP32 DEV module board. Details on getting started can be found here: https://f1atb.fr/programming-the-esp32-application-to-the-photovoltaic-router/

With the Arduino, integrate OTA mode into your code allowing you to update the code remotely via WIFI. So you will no longer need the USB/TTL interface

ESP Easy

Firmware allowing you to program ESP8266 or ESP32 and having the code for many sensors on the market. This simplifies programming
https://espeasy.readthedocs.io/en/latest/index.html

ESPHome

Powerful firmware allowing you to program your ESP32 with simple descriptions of interfaces, actions, events etc in a yaml file. Often associated with the Home Assistant home automation system.
https://esphome.io/index.html

Example of construction

Here an example grouping :

• IR sensor
• Luminosity sensor
• Sensor (DHT22) for temperature and humidity
• Buzzer as bell
• Interface to an On/Off switch
• Relay connected to the light