LilyGO T-Relay 4-Channel Relay Module is a versatile and powerful ESP32-based relay board designed for IoT, smart home automation, and industrial control. With 4 relays, optocoupler isolation, and 16 expansion GPIOs, this relay module supports a wide range of communication protocols including UART, SPI, I2C, CAN, I2S, and SDIO. It offers seamless wireless control via Wi-Fi 802.11 b/g/n and Bluetooth V4.2 BR/EDR & BLE, making it ideal for both industrial and hobbyist projects, including LoRa mesh networks and ESP32 automation systems. Specifications MCU ESP32 FLASH 4MB PS RAM 8MB Bus Interfaces UART, SPI, I2C, CAN, I2S, SDIO Wireless Wi-Fi 802.11 b/g/n Bluetooth BLE V4.2 Onboard Functions 4 Groups of relays Optocoupler Isolation 16 Expansion GPIO HRS4H-S-DC5V Relay: 4 Blue LEDs Relay Work Indicator①K1 Relay: GPIO21②K2 Relay: GPIO19③K3 Relay: GPIO18④K4 Relay: GPIO05 Support T-U2T Upload Tool:Computer → USB Type-C data cable → Connect to T-U2T USB to TTL downloader for programming. Fast, reliable, and compatible with all T-Relay ESP32 modules. USB cable also powers the board directly. Technology Support [Github] If you need technical support please check the link to find more details. T-Relay GitHub Repository Important Notes This product does not include a programmed download chip. To upload programs, a T-U2T Auto Downloader is required. If you don’t have the T-U2T, you will need to purchase it separately. If you already own a T-U2T, it is compatible with all T-Relay series products. Applications Smart Control: Ideal for smart home projects, industrial automation, and remote relay switching using ESP32 and Wi-Fi/Bluetooth connectivity. Relay Control: Perfect for controlling high-power devices with low-power microcontrollers like ESP32, using GPIO and optocoupler isolation for safety. IoT Applications: Use in Wi-Fi and Bluetooth-based IoT systems, including LoRa mesh networks, MQTT integration, and Node-RED dashboards. Size T-Relay W5500 Shield More Details Pin Diagram Includes: T-Relay 1 x Relay Module (ESP32-based) 2 x Pin Headers T-Relay T-U2T Kit 1 x Relay Module 2 x Pin Headers 1 x T-U2T USB to TTL Downloader T-Relay W5500 Shield
