T-Relay-8 - An ESP32 board with 8 relays

LilyGo T-Relay-8 is an ESP32 WiFi & BLE board equipped with eight 5V relays supporting up to 250V AC or 28V DC, as well as 16-pin GPIO header for expansion.

The board offers a more compact solution than the usual two-board setups with an ESP32 board and a separate 8-relay “Arduino” module, and also integrates optocouplers for improved safety.

LilyGo T-Relay-8 specifications:

Wireless module – ESP32-WROVER-E module with ESP32 dual-core processor with 2.4 GHz WiFi 4 and Bluetooth 4.2 connectivity, 4MB flash, 8MB PSRAM
Relays – 8x HRS4H-S-DC5V 5V relays up to 250VAC/10A or 28VDC/10A with octocoupler isolation, blue LEDs for status
Expansion – 16-pin header (unpopulated) with GPIOs, 3.3V, and GND
USB – 1x USB Type-C for programming via optional T-U2T dongle via CH9102 USB to TTL chip
Misc – Reset button, red user LED
Power Supply – 12V to 24V via 2-pin terminal block
Dimensions – 17 x 8.5 x 1.8 cm (the length is 17.5cm if the ESP32 module PCB antenna is taken into account)

The board can be programmed with the Arduino IDE or PlatformIO, and LilyGo provides instructions and code samples to control the relays through the Blynk IoT platform or a web server, as well as a simpler blinky sample of sort turning on and off the relays in sequence. Note that like many of LilyGo boards, T-Relay-8 does not come with an on-board USB-to-TTL chip, and instead, users would need to connect the T-U2T dongle based on the CH9102 chip to program the ESP32 module.

LilyGo T-Relay-8 ESP32 board can be purchased with two unsoldered GPIO headers for $22.38 including shipping, or $27.98 if you don’t have the required T-U2T dongle yet. If you can do with an ESP32 board with just 4 relays instead of 8, the T-Relay is sold for $10.37 plus shipping.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.