# Relay kit with ESP8266, ESP-01

> Relay kit with 5V relay and ESP8266 ESP-01 WiFi module mounted directly on the socket. Includes a built-in 5V-3.3V step-down converter for powering the ESP, relay controlled via GPIO0 with active LOW activation. The ESP-01 supports Station and Access Point modes, UART communication for configuration and programming. Compact solution for WiFi automation and remote control of loads, suitable for smart home and IoT projects.

- Page: https://sigmanortec.ro/en/relay-kit-with-esp8266-esp-01
- Price: 22.98 RON
- Availability: In stock; 1-2 zile
- Reference: 33410 · EAN: 5944779801473
- Category: Electronic components > Relays
- Package (shipping data): 0.017 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 05:45 (Europe/Bucharest)

## Description

Compact solution for WiFi automation and remote control of consumers, combines a 5V relay with the ESP8266 ESP-01 module mounted directly in the socket. Includes 5V-3.3V step-down for powering the ESP, relay controlled from GPIO0 with LOW activation, support for Station and Access Point modes and UART communication for configuration and programming.
This set combines a 5V powered relay module with an ESP8266 WiFi module of the ESP-01 type, for quick network automations. The relay module powers the ESP-01 board directly, which is inserted into the dedicated pins, and the ESP8266 can control the relay without other intermediary modules. It is a compact solution for remote control of various loads, ideal for smart home projects, simple automations, and IoT prototypes.
The relay module powers the esp01 board which is inserted directly onto the dedicated pins.
Allows automations via WiFi as the ESP module can directly control the relay.
Programming the ESP01 board requires a compatible programmer.
Github instructions here
Specifications:
Supply voltage: 5V
ESP-01S supply voltage: 3.3V
Voltage conversion: integrated step-down from 5V to 3.3V for powering the ESP
Relay control pin: GPIO0
Active LOW: LOW = ON, HIGH = OFF
ESP8266 ESP-01 / ESP-01S Specifications:
Chip: ESP8266
WiFi standard: 2.4 GHz 802.11 b/g/n
WiFi modes: Station, Access Point, Station + Access Point
Logic voltage: 3.3V
Power supply: 3.3V
Communication interface: UART serial TTL
Antenna: PCB integrated on module
Onboard LED: present
Usage:
Power the module at 5V according to the markings on the board.
Mount the ESP-01 on the dedicated connector, with correct orientation.
Configure and program the ESP8266 through UART at 3.3V, do not use 5V on the pins. A programmer is required.
Connect the module to the WiFi network and set the control method, for example HTTP, MQTT, or integration with an automation platform.
Control the relay from the local network or remotely, depending on the configuration.
Work carefully when connecting loads, and for 230V voltages use insulation, enclosure, and appropriate protection measures.
Programming ESP-01 with FTDI:
Important: use FTDI set to 3.3V, not 5V.
ESP01 to Programmer Connection Table:
ESP8266 ESP-01 / ESP-01S Pin
FTDI Converter Pin
Notes
RX
TX
Cross connection.
TX
RX
Cross connection.
VCC
VCC 3.3V
Power supply 3.3V.
CH_EN / EN
VCC 3.3V
Chip enable, keep it at 3.3V.
GPIO0
GND
Connect to GND only for programming mode.
GND
Common ground.
Entering upload mode:
Connect all wires according to the table.
Make sure GPIO0 is connected to GND.
Power the board from the FTDI.
Press RESET if your module has a button, otherwise unplug and plug in the power again.
Upload code:
In Arduino IDE, select the board Generic ESP8266 Module.
Select the correct serial port.
In the code, replace SSID and PASSWORD with your WiFi network.
Click Upload.
After uploading, disconnect GPIO0 from GND, then restart the module.
Serial Monitor and verification:
Open Serial Monitor.
Set the baud rate to 115200.
Check messages about WiFi connection and the used address.
Mounting on the relay module:
Turn off the power.
Insert ESP-01 / ESP-01S into the relay module socket, with the correct orientation.
Power the relay module at 5V.
Access the URL set in the code, for example https://192.168.0.178/
Code:
See the Test section.